Since early May 2026, Microsoft Threat Intelligence has observed Storm-2945, a sub-cluster of Midnight Blizzard, conducting widespread but targeted traffic manipulation attacks involving hospitality sector networks served by captive portals worldwide. Despite some tactic, technique, and procedure (TTP) similarities to the Forest Blizzard DNS hijacking operation that we publicly disclosed in April 2026, we attribute this campaign, which we call CaptiveCrunch, to Storm-2945. As reported by ReliaQuest on July 23, a portion of this activity leverages doppelganger domains mimicking Microsoft online services to conduct follow-on adversary-in-the-middle (AitM) phishing operations that abuse the device code authentication flow in Microsoft Entra ID. Microsoft Threat Intelligence has also identified active traffic manipulation attacks leading to the delivery of malware on impacted systems. Microsoft has observed Storm-2945 leveraging AI to support a significant portion of these operations.

Today, we are sharing our findings on these ongoing intrusions to raise awareness of this threat and enable customers to protect their devices, especially while traveling. We provide our assessment of Storm-2945’s relationship to Midnight Blizzard and analysis of the CaptiveCrunch campaign, detailing the malware and tradecraft used in these operations. We also provide mitigation, detection, and hunting guidance to help organizations identify and defend against Storm-2945 and related activity.

Microsoft Threat Intelligence would like to thank our partners at Anthropic and OpenAI for their collaboration and support during this investigation.

The CaptiveCrunch campaign

Since February 2026, Storm-2945 has conducted AI-augmented operations including targeted device code and OAuth code phishing campaigns leading to Entra device registration and subsequent data collection from Microsoft 365. Since early May 2026, Microsoft Threat Intelligence has observed Storm-2945 manipulating DNS and HTTP traffic from networks served by captive portals to redirect user traffic through actor-controlled infrastructure. Although our investigation into the initial compromise vector for the captive portal networks is ongoing, we have observed notable commonalities in the equipment and management systems used across multiple affected networks. These similarities suggest that the activity might not be limited to isolated compromises of individual venues and could reflect access to shared services within portions of the captive portal ecosystem.

As part of the CaptiveCrunch campaign, Storm-2945 has leveraged their AitM position to redirect users through actor-controlled phishing infrastructure and has also delivered malware purporting to be browser or operating system updates in response to automated connectivity checks issued by users’ browsers. Multiple variants have been delivered, including fully-featured Windows remote access trojans (RAT) in compiled Golang, with functionality to conduct system enumeration, collect files and keystrokes, steal credentials and session tokens, conduct audio and video surveillance, monitor for removable media, and provide the threat actor a remote shell on infected systems.  

The threat actor infrastructure leverages a variety of ClickFix techniques to elicit the user into downloading and executing the malware:

In addition to variants of malware targeting Windows systems, Microsoft Threat Intelligence is also aware of indications that the threat actor might be targeting Android devices with similar techniques as the ClickFix landings also include instructions for Android devices to download and install an APK file.

To date, Microsoft has identified widespread compromise of Wi-Fi networks at hospitality-related organizations and other networks serviced by captive portal equipment in several countries. ReliaQuest has identified this activity not only at hotels, but also conference centers and other shared venues, and assesses that the goal of this activity is to access the accounts of corporate travelers.

Storm-2945 and Midnight Blizzard

Microsoft Threat Intelligence assesses that Storm-2945 is an operational sub-cluster of Midnight Blizzard based on distinctive technical and operational overlaps. These include technical similarities to Storm-2372, a Midnight Blizzard initial access operations sub-cluster, also notable for their device code and OAuth code phishing operations tracked throughout 2025, Microsoft Graph-based email exfiltration, social engineering delivered via commercial messaging apps, and significant similarities in victimology.

Midnight Blizzard is a Russia-based threat actor attributed by the US and UK governments to the Foreign Intelligence Service of the Russian Federation, also known as the SVR. This threat actor is known to primarily target governments, diplomatic entities, non-governmental organizations (NGOs), and information technology (IT) service providers, primarily in the US and Europe. Midnight Blizzard is consistent and persistent in their operational targeting, and their objectives rarely change. Their focus is to collect intelligence through longstanding and dedicated espionage in support of Russian foreign policy interests.

Midnight Blizzard operations often involve compromise of valid accounts and, in some highly targeted cases, advanced techniques to compromise authentication mechanisms within an organization to expand access and evade detection. They utilize diverse initial access methods, and Midnight Blizzard is also adept at identifying and abusing OAuth applications to move laterally across cloud environments and for post-compromise activity, such as email collection.

CaptiveCrunch tradecraft and tooling

CornFlake: Remote access and infostealer implant

CornFlake is a full-featured Windows RAT written in Go that serves as Storm-2945’s primary persistent implant. Microsoft has observed the threat actor rapidly iterating on this malware layer, which features customizable capabilities from the social engineering user interface and data collection capabilities to anti-detection and evasion techniques.

On initial execution, CornFlake operates in dropper mode: it displays a convincing fake progress window designed to occupy the victim’s attention while the binary copies itself to %APPDATA%\svchost32\svchost32.exe and establishes persistence.

Fake window options configurable by the threat actor at build time:

• winupdate — A Windows Update screen displaying “Working on updates… Don’t turn off your computer”
• defender — A Windows Security virus scan
• directx — A DirectX End-User Runtime Web Installer
• vcredist — A Microsoft Visual C++ 2015-2022 Redistributable installer
• sysopt — A disk optimization utility
• netfix — A Windows Network Diagnostics tool
• browser — A browser update prompt
• pdfview — A document viewer installer

CornFlake registers as a Windows service named svchost32 with the display name “Cloud Sync Service” and description “Synchronizes files with the cloud storage provider”, deliberately mimicking the legitimate svchost.exe process. It establishes redundant persistence mechanisms: Windows service registrations, Registry Run keys, named scheduled tasks, and a persistence watchdog routine that runs continuously to restore any persistence mechanism that is removed by defenders or endpoint protection.

For command and control (C2), CornFlake performs an Elliptic Curve Diffie-Hellman (ECDH) P-256 ephemeral key exchange with the C2 server, derives a session key via SHA-256, and communicates over a custom JSON protocol framed within the encrypted channel. This provides an encrypted channel to the C2 server, with each C2 session using a unique ephemeral key, making decryption of captured traffic impossible without the session-specific private key. The runtime configuration file sync.dat supports hot reconfiguration of C2 servers, watched directories, file targeting patterns, and Transport Layer Security (TLS) settings without requiring redeployment.

Once established on a victim system, CornFlake provides the operator with a comprehensive collection toolkit, gated by configuration flags that allow selective activation post-deployment:

CornFlake also exposes a localhost HTTP API server (/upload, /reload, /status) that transforms the RAT into a modular platform: companion or next-stage payloads such as ChocoShell could task file exfiltration, trigger configuration hot reloads or check C2 connectivity using the pre-established secure C2 channel for communication.

ChocoShell: PowerShell infostealer

ChocoShell is the campaign’s Powershell-based infostealer, delivered and executed entirely in-memory. Its primary objective is the high-volume theft of browser session cookies, saved passwords, Microsoft 365 Single Sign-On (SSO) tokens, and Wi-Fi credentials from compromised systems. Where CornFlake provides the operator with a persistent, long-running foothold on the device, ChocoShell is designed to extract the most operationally valuable credentials, giving the operator access to victim cloud environments.

The ChocoShell script was authored with full developer comments that reveal the operator’s intent behind each code decision, including explicit references to Microsoft detection signatures and the reasoning behind specific evasion choices. The consistent coding standard and descriptive commentary suggest the author might have leveraged AI-assisted code generation.

Defense evasion. Upon execution, ChocoShell beacons to a hardcoded C2 server at 213.145.86[.]112 and implements several evasion techniques in sequence. It disables the Antimalware Scan Interface (AMSI) via .NET reflection to prevent ScriptBlock scanning and evades Microsoft behavioral detection that triggers on suspicious PowerShell web request cmdlets. A timing-based sandbox detection check is also employed as a virtual machine (VM) detection mechanism, silently exiting without performing any collection if detected.

C2 communication. ChocoShell communicates with its C2 server using HTTPS with URI paths designed to blend in with legitimate web traffic. Beacons use /t/pixel.gif?m=<status>, mimicking an image tracking pixel. Additional tooling is fetched from /cdn/chunks/polyfill-7e2b.min.js, disguised as a JavaScript polyfill file. This downloaded module is Base64-decoded and executed in memory via [ScriptBlock]::Create(), providing browser encryption key extraction capabilities, SYSTEM token impersonation, and Defender signature locking. Exfiltrated data is sent by POST to /t/event as GZip-compressed, Base64-wrapped JSON.

Privilege escalation. ChocoShell requires administrative privileges for its most impactful capabilities: SYSTEM token impersonation for Chrome ABE decryption, Volume Shadow Copy Service (VSS) shadow copy creation, Defender signature locking. It implements three silent UAC bypass techniques with ordered fallback:

1. SilentCleanup task hijack: Writes a malicious command to HKCU\Environment\windir, then triggers the built-in SilentCleanup scheduled task, which resolves %windir% from the user’s environment, executing the threat actor’s command at elevated privilege. The registry value is cleaned up after two seconds to avoid cloud detection.
2. wsreset.exe COM hijack: Creates a COM handler key in HKCU\Software\Classes and launches the auto-elevating Windows Store reset tool.
3. sdclt.exe folder hijack: Hijacks HKCU\Software\Classes\Folder\shell\open\command and launches the Windows Backup utility with the /KickOffElev flag.

If none of the silent bypasses succeed (for example, the user is not a local administrator), ChocoShell falls back to a visible UAC prompt via Start-Process -Verb RunAs. Notably, the script also contains a variant designed to execute within the WinGet Desired State Configuration (DSC) host process (ConfigurationRemotingServer), suggesting an attack vector through malicious WinGet DSC configuration used in Windows machine provisioning.

Credential and session theft. Once running with elevated permissions, ChocoShell locks Defender signature updates and systematically harvests data from multiple sources. For Chromium-based browsers (Chrome, Edge, Brave, Opera, Opera GX, Vivaldi), it extracts the master encryption key from the browser’s Local State file, handling both the modern ABE scheme (Chrome v127+) and the legacy data protection API (DPAPI)-only scheme. ABE decryption requires SYSTEM-level DPAPI access, which the malware obtains by impersonating a SYSTEM process token borrowed from winlogon.exe, wininit.exe, or services.exe. Locked browser SQLite databases are accessed through three strategies: shared file access, Volume Shadow Service snapshots, and direct copy as a fallback.

As a parallel collection path, ChocoShell launches Chrome, Edge, and Brave with the –remote-debugging-port flag and issues Network.getAllCookies through the Chrome DevTools Protocol (CDP). This completely bypasses ABE, enabling the browser to perform its own internal decryption and returns plaintext cookie values. To handle privilege issues (SYSTEM-launched browsers inherit the wrong token), the malware creates transient scheduled tasks with TASK_LOGON_INTERACTIVE_TOKEN to launch the browser under the signed-in user’s session. After extraction, the browser is stopped and relaunched with –restore-last-session to avoid alerting the user.

For Firefox family browsers (Firefox, Waterfox, LibreWolf, Floorp, Zen), the malware copies unencrypted cookies.sqlite databases from each profile. Additionally, ChocoShell collects Microsoft 365 and Azure Active Directory (AD) access tokens, refresh tokens, and Web Account Manager (WAM) tokens from .tbres files in the Token Broker cache. Collection of these tokens represents a significant threat to enterprise environments, as threat actors could replay SSO sessions without browser cookies. Additionally, Wi-Fi credentials are harvested via netsh wlan show profile with key=clear.

Exfiltration and cleanup. All collected data is aggregated into a JSON structure, GZip-compressed, Base64-encoded, and sent by POST to the C2’s /t/event endpoint. After exfiltration, all collected data variables are nulled, garbage collection is forced, VSS shadow copies are deleted via Windows Management Instrumentation (WMI), temporary elevation scripts are removed, and all UAC bypass registry keys (already cleaned during escalation) are verified removed.

FruitStone: Operator C2 panel

FruitStone is the web-based C2 panel that Storm-2945 operators use to manage the entire CaptiveCrunch campaign infrastructure. Implemented as a single-page application (HTML and JavaScript) serving as the front-end of the C2 server with all functionality exposed without authentication, FruitStone provides a centralized dashboard for managing compromised endpoints, building and deploying new campaign payloads, and reviewing all collected data (such as screenshots, keystrokes, browser credentials).

Operational cover. The panel is branded as “CloudSync Console” with a footer reading “Acuity Systems, Inc. — Cloud Infrastructure Portal v3.2.1,” designed to appear as legitimate enterprise cloud management software if the panel URL is discovered by defenders or hosting providers. This masquerading extends to the CornFlake agent’s service name (Cloud Sync Service) and description (“Synchronizes files with the cloud storage provider”), creating a consistent cover story across the toolchain.

Session management and multi-operator support. FruitStone uses JSON Web Token (JWT)-based authentication, session revocation, and rate limiting with IP blocking to prevent brute force attacks against the panel sign in. Multiple operators could be provisioned with individual accounts, and all active sessions are visible with IP address, user-agent, and creation time to enable operational security awareness across the operators.

Agent management. The panel displays all registered CornFlake agents in a dashboard with real-time status updates via Server-Sent Events (SSE). Each agent card shows comprehensive system information including hostname, username, OS version, CPU, RAM, disk usage, screen resolution, timezone, domain membership, and camera/microphone presence, all collected during the CornFlake posture sweep. Agents are grouped by country and subnet, with geographic distribution visualized on a map.

Operators could interact with individual agents through:

• Remote shell — Interactive cmd.exe or PowerShell command execution with command history
• File system browser — Live directory traversal and arbitrary file download from compromised hosts
• Collection tasking — On-demand screenshot, process list, keylog buffer flush, clipboard dump, security posture survey, ChromeKatz cookie/password extraction, camera capture, and audio recording
• Configuration push — Live runtime reconfiguration of C2 servers, watch paths, and C2 beacon timing
• Agent update — In-place implant update by pushing a new CornFlake build to a running agent
• Agent kill — Remote termination of the CornFlake implant

Campaign builder. A step-by-step wizard enables operators to configure and build new CornFlake payloads directly from the panel:

1. Identity — Campaign ID, C2 host and port, HTTP base URL, executable file name (svchost32.exe by default), and dropper type (C dropper at ~19 KB, Go stub at ~8 MB, or standalone self-installer)

2. Capabilities — Toggle individual collection modules: screenshots, process enumeration, keylogging, clipboard monitoring, posture survey, file exfiltration, and ChromeKatz browser credential theft

3. File Paths — Configure targeted directories and file extensions by category (documents, archives, images, code, data, emails, encryption keys)

4. Evasion — Enable garble symbol randomization (for GoLang payloads), XOR string encoding, GZip upload compression, and debug mode

Infrastructure management. FruitStone provides management interfaces for three layers of supporting infrastructure:

• Proxy relays — Multi-proxy C2 relay architecture with TLS certificate tracking (fingerprint, expiry), health checks, connection counts, bytes forwarded, and rotation capabilities that push updated server lists to all online agents
• Beacon profiles — Configurable timing profiles controlling agent sleep intervals, reconnection delays, TLS Server Name Indication (SNI) spoofing (like teams.microsoft.com), and DNS fallback domains
• Staging servers — External payload hosting infrastructure with push-to-deploy, file listing, and health monitoring

Device code abuse for cloud access

Since July 16, Microsoft has observed a portion of CaptiveCrunch landing pages redirecting users to device code authentication flow experiences. In these cases, users served these landings might be instructed to enter a device code into a legitimate Microsoft sign-in page, a technique commonly referred to as device code phishing.

Device code authentication is a legitimate OAuth workflow designed for devices that cannot support a traditional sign-in experience. However, threat actors could abuse this flow by initiating an authentication request on behalf of a user then convincing the user to enter an actor-controlled device code into a legitimate Microsoft authentication page. When successful, the victim authenticates the threat actor’s session rather than their own.

This activity is consistent with previously reported device code phishing operations conducted by Midnight Blizzard since August 2024. The observed technique does not appear fundamentally novel; however, integrating device code phishing into captive portal and traffic manipulation operations might increase the likelihood that users perceive the authentication request as legitimate. For additional details on Midnight Blizzard-related device code phishing techniques, see: Storm-2372 conducts device code phishing campaign. To understand other threat actors’ use of device code phishing and associated mitigations, see Inside an AI‑enabled device code phishing campaign.

How to protect against CaptiveCrunch activity

Minimize trust in hospitality and guest networks

When traveling, users should treat hotel, conference, airport, and other guest wireless networks as untrustworthy.

• Prefer private connectivity (including mobile hotspots, satellite, and eSIM-based cellular data connections) over public Wi‑Fi whenever practical.
  • For enterprise-managed devices, organizations can choose to prevent Wi-Fi connections to networks that have not been provisioned via Mobile Device Management (MDM). See: https://learn.microsoft.com/windows/client-management/mdm/policy-csp-wifi#allowmanualwificonfiguration
• Consider using enterprise-managed travel routers or hotspot devices that establish encrypted tunnels back to trusted corporate infrastructure before accessing sensitive resources.
• Avoid downloading software updates, certificates, browser updates, network troubleshooting tools, or security utilities presented through captive portals or other unexpected web prompts.
• Verify update requests through trusted operating system mechanisms rather than pop-up messages or website prompts.

Strengthen identity and access controls

Organizations should assume that public and hospitality network infrastructure might not be trustworthy and should adopt controls that limit exposure to traffic manipulation, credential theft, and device code phishing.

• Educate users to recognize ClickFix-style prompts, fake verification checks, and paste-and-run instructions as malicious, especially when they invoke command interpreters or script hosts such as cmd.exe, PowerShell, rundll32.exe, or mshta.exe.
• Use passwordless solutions like passkeys and implement multifactor authentication (MFA).
  • Use the Microsoft Authenticator app for passkeys and MFA, and complement MFA with conditional access policies, where sign-in requests are evaluated using additional identity-driven signals.
  • Conditional access policies can also be scoped to strengthen privileged accounts with phishing resistant MFA.
  • Your passkey and MFA policy can be further secured by only allowing MFA and passkey registrations from trusted locations and devices.
• Only allow device code flow where necessary. Microsoft recommends blocking device code flow wherever possible. Where necessary, configure Microsoft Entra ID’s device code flow in your Conditional Access policies.
• Implement a sign-in risk policy to automate response to risky sign-ins. A sign-in risk represents the probability that a given authentication request is not authorized by the identity owner. A sign-in risk-based policy can be implemented by adding a sign-in risk condition to Conditional Access policies that evaluates the risk level of a specific user or group. Based on the risk level (high/medium/low), a policy can be configured to block access or force MFA.
  • When a user is a high risk and Conditional access evaluation is enabled, the user’s access is revoked, and they are forced to re-authenticate.
  • For regular activity monitoring, use Risky sign-in reports, which surface attempted and successful user access activities where the legitimate owner might not have performed the sign-in. 
• Use a Security Service Edge (SSE) solution like Global Secure Access to secure access to any app or resource using network, identity, and endpoint access controls.

Reduce exposure during captive portal registration

Organizations should review what information employees provide to hospitality providers when connecting to guest networks.

• Do not reuse corporate credentials on hotel, conference, or guest-network registration pages.
• Where possible, organizations should evaluate whether venue-provided wireless is required for corporate events and conferences.
• Organizations should minimize unnecessary disclosure of employee identities, organizational affiliations, and travel details when booking accommodations or registering for guest network access, consistent with corporate policy and applicable local requirements.

Microsoft Defender detections and hunting guidance

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender for Endpoint detects Storm-2945 activity under the detection Suspicious activity linked to a Russian state-sponsored threat actor has been detected. However, these alerts might be triggered by unrelated threat actor activity. The following chart lists Microsoft Defender detections specific to the TTPs utilized by Storm-2945 in this attack.

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

• Actor profile: Midnight Blizzard

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Hunting queries

Microsoft Defender XDR

Microsoft Defender XDR customers can run the following advanced hunting queries to find related activity in their networks:

Detect file creation after Wi-Fi connectivity test on devices

The following query checks for a file creation on a device within two minutes of the device performing built‑in Network Connectivity Status Indicator (NCSI) test, which occurs when network connectivity is established to a Wi-Fi network with a captive portal. This activity might indicate an attacker’s initial access file presence on a device.

Please note that not all files discovered through this query might be malicious or related to this threat activity.

let ncsi_endpoints = dynamic(["msftconnecttest.com","edge-http.microsoft.com","msftncsi.com","captive.apple.com","clients1.google.com",
    "clients3.google.com","clients4.google.com","clients6.google.com","connectivitycheck.gstatic.com","connectivitycheck.android.com",
    "android.clients.google.com","www.gstatic.com","detectportal.firefox.com","detectportal.brave-http-only.com","cloudflareportal.com",
    "cloudflarecp.com","cloudflareok.com","connectivity-check.warp-svc","connectivity.cloudflareclient.com","spectrum.s3.amazonaws.com",
    "nmcheck.gnome.org"]);
let NCSIEvents = DeviceNetworkEvents
    | where Timestamp > ago(7d)
    | where RemoteUrl has_any (ncsi_endpoints)
    | project NCSI_Timestamp = Timestamp, DeviceId, DeviceName, RemoteUrl, NCSI_ReportId = ReportId, NCSI_InitiatingProcessFileName = InitiatingProcessFileName, NCSI_InitiatingProcessCommandLine = InitiatingProcessCommandLine, NCSI_AccountName = InitiatingProcessAccountName;
let FileDownloadEvents = DeviceFileEvents
    | where Timestamp > ago(7d)
    | where ActionType == "FileCreated"
    | where FileName has_any (".exe",".msi",".zip",".rar",".7z")
    | project Download_Timestamp = Timestamp, DeviceId, FileName, FolderPath, Download_ReportId = ReportId, Download_InitiatingProcessFileName = InitiatingProcessFileName, Download_InitiatingProcessCommandLine = InitiatingProcessCommandLine, Download_AccountName = InitiatingProcessAccountName;
NCSIEvents
| join kind=inner (
    FileDownloadEvents
) on DeviceId
| where Download_Timestamp >= NCSI_Timestamp and Download_Timestamp 

Detect connectivity to Storm-2945 infrastructure

The following query checks for connectivity to Storm-2945 infrastructure observed in this attack activity.

let target_domains = dynamic(["ms365-device.com", "ms365-live.com", "m365-owa.com", "owa-ms365.com"]);
let target_ips = dynamic(["31.57.243.154", "38.146.28.75", "38.146.28.132", "104.194.159.150", "107.189.26.194", "213.145.86.112"]);
DeviceNetworkEvents
| where RemoteUrl has_any(target_domains) or RemoteIP in (target_ips)
| project
    Timestamp,
    DeviceName,
    DeviceId,
    RemoteUrl,
    RemoteIP,
    LocalIP,
    InitiatingProcessFileName,
    InitiatingProcessCommandLine,
    AccountName = InitiatingProcessAccountName,
    ReportId

Detect CornFlake RAT presence on affected systems

The following query checks for the presence of the CornFlake RAT binary.

DeviceProcessEvents
| where FolderPath == "%APPDATA%\\svchost32\\svchost32.exe"
   or FolderPath endswith @"\svchost32\svchost32.exe"
| project Timestamp, DeviceName, DeviceId, FileName, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine, AccountName, ReportId

Detect CornFlake RAT Windows service registration

The following query checks for the CornFlake RAT Windows service registration.

DeviceRegistryEvents
| where RegistryKey has @"\SYSTEM\CurrentControlSet\Services\svchost32"
| where ActionType == "RegistryValueSet"
| where (RegistryValueName == "DisplayName" and RegistryValueData == "Cloud Sync Service")
    or (RegistryValueName == "Description" and RegistryValueData == "Synchronizes files with the cloud storage provider")
| project
    Timestamp,
    DeviceName,
    DeviceId,
    RegistryKey,
    RegistryValueName,
    RegistryValueData,
    ActionType,
    InitiatingProcessFileName,
    InitiatingProcessCommandLine,
    InitiatingProcessAccountName,
    ReportId

Microsoft Sentinel

Microsoft Sentinel customers can use the TI Mapping analytics (a series of analytics all prefixed with ‘TI map’) to automatically match the malicious domain indicators mentioned in this blog post with data in their workspace. If the TI Map analytics are not currently deployed, customers can install the Threat Intelligence solution from the Microsoft Sentinel Content Hub to have the analytics rule deployed in their Sentinel workspace.

Detect network IP and domain indicators of compromise using ASIM

The following query checks IP addresses and domain IOCs across data sources supported by ASIM network session parser:

//IP list and domain list- _Im_NetworkSession
let lookback = 30d;
let ioc_ip_addr = dynamic(["213.145.86.112"]);
let ioc_domains = dynamic(["213.145.86.112/t/pixel.gif", "213.145.86.112/cdn/chunks/polyfill-7e2b.min.js", "213.145.86.112/t/event"]);
_Im_NetworkSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or DstDomain has_any (ioc_domains)
| summarize imNWS_mintime=min(TimeGenerated), imNWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, DstDomain, Dvc, EventProduct, EventVendor

Detect web sessions IP and file hash indicators of compromise using ASIM

The following query checks IP addresses, domains, and file hash IOCs across data sources supported by ASIM web session parser:

//IP list - _Im_WebSession
let lookback = 30d;
let ioc_ip_addr = dynamic(["213.145.86.112"]);
let ioc_sha_hashes =dynamic([“918fa52ae45ed60ba7cc8bdc99c3cbe9ab92e0375ec31fc05d0d4513be11c593”, “be99857449d2856dd5a84e21c8a3d5e0e01456adb44062ddec5a6b4970d8d42c”]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstIpAddr in (ioc_ip_addr) or FileSHA256 in (ioc_sha_hashes)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Detect domain and URL indicators of compromise using ASIM

The following query checks domain and URL IOCs across data sources supported by ASIM web session parser:

// file hash list - imFileEvent
// Domain list - _Im_WebSession
let ioc_domains = dynamic(["https://213.145.86.112/t/pixel.gif", "https://213.145.86.112/cdn/chunks/polyfill-7e2b.min.js", "https://213.145.86.112/t/event"]);
_Im_WebSession (url_has_any = ioc_domains)

ChocoShell C2 communications

The following query detects ChocoShell communications with its C2 server using HTTPS with URI paths designed to blend in with legitimate web traffic. Beacons use /t/pixel.gif?m=<status>, mimicking an image tracking pixel.

let lookback = 30d;
let ioc_url_artifacts = dynamic(["/t/pixel.gif?m="]);
_Im_WebSession(starttime=todatetime(ago(lookback)), endtime=now())
| where DstDomain  in (ioc_url_artifacts)
| summarize imWS_mintime=min(TimeGenerated), imWS_maxtime=max(TimeGenerated),
  EventCount=count() by SrcIpAddr, DstIpAddr, Url, Dvc, EventProduct, EventVendor

Indicators of compromise

References

• https://reliaquest.com/blog/threat-spotlight-dns-poisoning-tactics-expand-to-hospitality/
• https://www.volexity.com/blog/2025/02/13/multiple-russian-threat-actors-targeting-microsoft-device-code-authentication

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

To get notified about new publications and to join discussions on social media, follow us on LinkedIn, X (formerly Twitter), and Bluesky.

To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.

The post CaptiveCrunch: Midnight Blizzard targets travelers worldwide for malware delivery and credential theft appeared first on Microsoft Security Blog.

Every organization needs security that protects end to end with the speed and scale of AI. Microsoft’s vision is simple: security should be ambient and autonomous, just like the AI it protects.

As organizations scale AI and expand across environments, security teams need protection that covers every surface. This month’s updates help security and IT teams secure their AI environments, use AI to defend at speed and scale, and strengthen the foundations that AI-powered operations depend on. Here’s what’s new:

Project Perception brings agentic defense to security operations

Project Perception, newly announced, is a coordinated system of specialized agents, cybersecurity-focused models, and enterprise-wide signals that transform how security operates. The agents work as a team: red team agents expose weaknesses, blue team agents investigate cyberthreats, and green agents harden what’s found. These multi-agent autonomous workflows work as a team to operate in continuous loops to execute end-to-end security workflows.

Microsoft Defender secures the full AI attack surface, from inbox to cloud

Expanded Microsoft Defender protections are designed to reduce risks associated with day-to-day AI interactions, from email inboxes to cloud agent environments. New prompt injection protection in Microsoft Defender, now in preview, identifies and isolates emails containing malicious AI instructions before delivery, reducing the risk of prompt injection attacks reaching the inbox. Unified Defender posture and runtime protection for cloud agents in Microsoft Agent 365 consolidates security posture assessment and runtime protection for Microsoft Foundry, Microsoft Copilot Studio, and third party-managed agents, helping teams reduce AI-specific risk across the agent estate.

Accelerate detection, prioritization, and response with AI embedded in SecOps workflows

Security teams can accelerate detection, prioritization, and response to cyberthreats with AI embedded directly into security operations (SecOps) workflows through Microsoft Defender. Threat intelligence enhancements, including Microsoft Defender Threat Intelligence convergence and an enhanced Threat Intelligence Agent, bring more out-of-the-box intelligence and automation into the unified SecOps workflow, so teams can move from summary to action.

Strengthen the cloud, code, and identity foundations AI depends on

Microsoft Defender is strengthening the foundational protections that AI-era operations depend on across cloud, code, and identity. Cloud Security Posture Management extends coverage to serverless containers, giving teams visibility and continuous posture assessment across containerized workloads running on Azure Container Apps, Azure Container Instances, and Amazon Web Services Elastic Container Service (AWS ECS) on Fargate. New interconnected experiences between Defender and Microsoft Entra empower the security operations center (SOC) to disable compromised identities directly using a role-based access control (RBAC) mode that maintains least privilege. Microsoft Defender Experts services are also expanding: Microsoft Defender Experts Threat Intelligence delivers human-led, curated insight into the cyberthreats most relevant to each organization, and Microsoft Defender Experts MDR extends expert-run detection and response beyond the Microsoft estate into third-party and multicloud signals through Microsoft Sentinel.

Microsoft Entra strengthens identity across the AI-powered enterprise

Strengthen identity foundations for AI-powered operations

New capabilities in Microsoft Entra are designed to strengthen the identity foundations that AI-powered operations depend on. Tenant governance helps organizations discover, manage, and govern tenants across their environment with centralized policies and cross-tenant delegated administration. Microsoft Entra ID is making passkeys the default authentication experience, which helps reduce reliance on SMS and voice, strengthens phishing-resistant security, and makes for an easier transition away from Microsoft-provided telecom delivery, which will retire in 2027. Through new interconnected Entra and Defender experiences, identity and access management and SOC teams share user experience, RBAC, and agentic workflows that eliminate product seams so identity and security operations can work together.

Protect sensitive data in motion across software as a service (SaaS) and AI apps with Microsoft Purview and Microsoft Entra

Microsoft Purview now integrates with Microsoft Entra Internet Access to extend data security to the network layer, enabling real-time protection of sensitive data shared with unmanaged cloud and AI apps over the network. For example, when an employee attempts to upload sensitive customer data or proprietary information, including text and files, into shadow AI apps, sharing is detected and blocked before the data is leaked from the organization. Organizations now have a unified Microsoft solution to gain visibility into where organizational data is shared externally, to detect and block sensitive data in transit, and to enable consistent data protection across their environment without relying on third-party solutions.

Microsoft Purview strengthens data security, compliance, and investigation for AI

A new Microsoft Purview Data Loss Prevention (DLP) for Microsoft 365 Copilot protection, available in preview, now gives data security teams greater control over how Copilot leverages email content, given external sources can introduce sensitive, third-party, or unvetted information that organizations may not want to rely on. Now admins can exclude emails from external senders from being referenced, summarized, or used as grounding data for Copilot. For example, with this DLP policy in place, an employee working with an external collaborator can still rely on Copilot to leverage internal insights, while external conversations are automatically excluded from Copilot-generated responses. With the native integration between Microsoft Purview and Microsoft 365 Copilot, organizations can extend controls to AI interactions with minimal additional configuration, resulting in a more predictable and policy-aligned AI environment.

A new centralized Microsoft Purview Insider Risk Management alert experience simplifies the prioritization of the most pressing data risks by bringing agentic alert triage, enriched user details, and expanded analysis capabilities (such as notes infused on the Insider Risk Management case) into a single view. Helping power this experience, the Data Security Triage Agent includes an advanced AI reasoning layer, now generally available, that performs deeper, multi-step analysis across user, device, and data activity signals to surface the incidents most likely to require investigation while reducing noise. Analysts can filter across classic and Data Security Triage Agent attributes on a single page, preview agent summaries and user details without switching views, and document findings while the system automatically records status changes and escalations to maintain a clear investigation history. Together, the Insider Risk Management alert experience and Data Security Triage Agent help security teams investigate faster and with greater confidence.

Advanced endpoint management now broadly available

As of July 1, 2026, the capabilities of the Microsoft Intune Suite are included in Microsoft 365 E5, with select capabilities also available in Microsoft 365 E3, bringing advanced endpoint management to more organizations without added cost. IT and security teams can now apply advanced endpoint management capabilities to reduce standing admin rights, modernize certificate management, resolve issues quickly, streamline app delivery, and bring AI into workflows with Microsoft Security Copilot in Intune. Together, these capabilities strengthen the endpoint foundations that AI-powered operations depend on. See everything that’s now included in your plan and how to start putting it to work.

Stay In the Loop

Microsoft Security is focused on delivering innovations across our portfolio, along with research-driven insights and reports for the security community. In the Loop posts are your reliable source of what’s new across Microsoft Security and what it means for your security strategy. Check back for the next drop.

To learn more about Microsoft Security solutions, visit our website. Bookmark the Security blog to keep up with our expert coverage on security matters. Also, follow us on LinkedIn (Microsoft Security) and X (@MSFTSecurity) for the latest news and updates on cybersecurity.

The post ​​​​What’s new in Microsoft Security: July 2026 appeared first on Microsoft Security Blog.

As organizations move beyond AI experimentation, success will depend on how effectively they combine intelligence and trust. The same systems that amplify knowledge, accelerate decisions, and unlock new outcomes must also protect data, govern AI, and build resilience. In this next phase of transformation, security is not separate from innovation—it is an enabler that helps make responsible innovation possible at a faster pace. That starts with asking better questions—the kind that help organizations turn intelligence into action and trust into a foundation for progress. 

AI is changing how security decisions are made. Defenders now have access to more signals, insights, and analytical power than ever before. But better security does not start with more information. It starts with asking the right questions: What are we trying to protect? What risks matter most? What conditions need to be true? And what decisions do we need to make with confidence? 

That clarity matters because security is shaped by more than technology. The challenges organizations face rarely exist in isolation. They emerge across people, processes, technology, data, identities, and governance. Understanding those connections is what allows security teams to use platforms, AI, and automation to make better decisions under real-world conditions. 

Security as a systems challenge 

Security has never been a single-layer challenge. Vulnerabilities can emerge across code, data, identities, and integrations, while exposure is often created at the intersections between them. Designing for security requires a systems mindset—understanding how these elements work together, where failure can occur, and what safeguards are needed so no single layer carries the burden alone. That is why defense in depth remains essential: layered controls, ongoing monitoring, mitigations, and risk management across the AI lifecycle help organizations reduce exposure while continuing to adapt. 

This is especially important as AI becomes more embedded in how organizations operate. AI can help teams analyze vast amounts of information, identify patterns, and surface recommendations at a scale that was previously unthinkable. Those AI outputs still require oversight, governance, and human judgment, with clear accountability for how AI-generated insights are validated and used. But insight only creates value when it is grounded in the right context and connected to action. 

AI-generated insights still require validation, oversight, and resilience planning because AI systems can produce incomplete or inaccurate outputs.

Clarity creates better decisions 

The most important security decisions start with a clear view of the risk, the level of control or visibility required, and the outcome the system is designed to achieve. When we optimize for capability over context, we miss how security decisions are actually made: through signals, expertise, validation, and judgment. This becomes even more important as AI expands what is possible. Better analysis can surface more insights, but better decisions still depend on understanding what matters most and applying the right context. That matters most when conditions are changing quickly, and teams need to act before every answer is certain. 

Threat intelligence offers a useful example. Defenders operate in environments defined by ambiguity, incomplete information, and rapidly changing conditions. Success rarely comes from a single source or signal. It comes from combining multiple forms of intelligence, applying expertise, validating assumptions, and connecting insights in ways that strengthen assurance.  

The lesson extends beyond threat intelligence. Different security objectives require different combinations of signals, analysis, and human judgment. Resilient decisions come from bringing those elements together thoughtfully, rather than relying on a single source of truth or assuming technology alone can provide the answer. 

Designing for better outcomes  

As AI becomes more embedded in security operations, the quality of our outcomes depends on how clearly we define the objectives we are trying to achieve. Security leaders create the most value when they identify the risks that matter most, the conditions that need to be true, and the systems required to support better decisions. 

Then we design for those outcomes through the right mix of controls, safeguards, and decision-making processes. This shows up not just in architecture, but in how teams establish guardrails, validate assumptions, and respond to the unexpected. The aim is not to make security harder for defenders. It is to make the work easier to execute, supported by platforms, tooling, and AI that help deliver greater speed, accuracy, and confidence. 

The systems we are building today do not exist in isolation. They interact with people, shape decisions, and operate at a scale that can amplify both strengths and weaknesses. Our responsibility extends beyond technology choices. We have to help organizations design systems they can understand, govern, and rely on with confidence as complexity grows. 

Trust is not something we can take for granted, and that does not change in the era of AI. It is built through deliberate choices: the controls we establish, the visibility we create, the assumptions we validate, and the safeguards we put in place. As AI becomes more embedded in how organizations operate, security leaders have a responsibility to help build confidence in the systems people rely on every day. 

Building trustworthy AI systems requires governance, security, privacy protections, transparency, and accountability across the full technology stack, aligned to responsible AI principles and standards.

The risk is not simply that we choose the wrong tool, model, or platform. The greater risk is believing that one answer can solve a complex, evolving problem. AI can help teams make sense of complexity, but it does not eliminate the need for judgment. If anything, it raises the importance of defining the right outcomes and designing systems that make the right actions easier to take. 

Better security starts with better questions, and with the clarity to act on them. The organizations that succeed will apply AI thoughtfully, define outcomes clearly, and combine analytical power with the expertise, judgment, and adaptability needed to build more resilient systems in the age of AI. 

To learn more about Microsoft Security solutions, visit our website. Bookmark the Security blog to keep up with our expert coverage on security matters. Also, follow us on LinkedIn (Microsoft Security) and X (@MSFTSecurity) for the latest news and updates on cybersecurity.

The post ​​Better security starts with better questions appeared first on Microsoft Security Blog.

Why security needs a new Cyber Stack — Introducing Project Perception

The physics of cybersecurity are changing. Autonomous systems can now reason, adapt and operate continuously. At the same time, the cost of offense is falling, while the volume, velocity and complexity of what must be secured continues to grow. Attackers can generate exploits faster, scale campaigns further and operate with unprecedented efficiency. The approaches built for a world of human actors cannot keep pace with a world of AI, agents and machine-speed attacks.

Security needs a new Cyber Stack. A new Cyber Stack must continuously perceive risk across the entire digital estate, reason across vast amounts of context and take action at machine speed. It must learn and adapt as environments evolve, helping organizations stay ahead of threats. And because security is ultimately a human mission, it must amplify defenders with better insights and more powerful ways to act. The defining characteristic of the next generation of security systems will not be their ability to generate more alerts. It will be their ability to continuously perceive, reason and act.

That vision led us to build Project Perception. A new agentic security system designed for the realities of AI. It turns signals into real-time protections using AI to defend against AI.

Project Perception brings together signals, context, models and specialized agents into a continuously learning system of defense. It can reason, prioritize and act at machine speed while keeping humans firmly in control and empowering them with powerful new workflows.

Project Perception is based on a simple idea: effective defense requires continuous understanding of how an attacker sees the world, how a defender evaluates risk and how protections are improved over time. To accomplish this, Perception coordinates three classes of specialized agents. Red team agents identify potential paths to compromise before an attacker can exploit them. Blue team agents investigate, reason over context and determine what represents meaningful risk. Green team agents take corrective actions and strengthen defenses across the environment. Working together, these agents form a closed-loop system that continuously discovers, evaluates and improves an organization’s security posture.

A system like Project Perception is only as effective as the visibility it has, the actions it can take, the experience of the teams building it and the models it can use. Microsoft brings together all four.

We see across identities, endpoints, applications, data, clouds and AI systems, providing broad visibility across the digital estate. Equally important, we can help customers take action across those environments. Combined with decades of security research, threat intelligence and real-world operational experience defending organizations, these capabilities shape how Project Perception reasons, prioritizes and responds.

Security is a 24/7 mission. Organizations need protection that is highly effective, continuously available and affordable at scale. That requires more than access to the most capable model. It requires applying the right model to the right task. Project Perception adopts a multi-model architecture that combines frontier and specialized cyber models, optimizing for both quality and cost.

As part of this multi-model strategy, we are committed to bringing customers the best models for each security task, including innovating with our own specialized models. The first scenario is software vulnerability management, bringing MAI-Cyber-1-Flash inside MDASH, our software vulnerability multi-model team of agents. MDASH with MAI-Cyber-1-Flash delivers 96% on CyberGym, an industry leading benchmark, +12 points above Mythos. And this same configuration delivers almost 50% of cost savings vs. the current MDASH configuration in market today. That’s the power of a well-tuned, multi-model system with access to uniquely rich historical training data. Next, Project Perception will take advantage of MAI-Cyber-1-Flash for many more security workflows, beyond the software vulnerability scenario.

We are bringing this vision to customers around the world through Project Perception, which enters public preview on August 3.

YouTube Video

A Cyber Stack built for agentic security

Delivering agentic security requires more than adding agents to existing workflows. It requires a new Cyber Stack, designed from the ground up.

The stack begins with signals and sensors that provide awareness across the digital estate. Security context transforms those signals into token-efficient understanding that agents can use. Models provide intelligence and reasoning. A harness coordinates models and agents across security workflows. Agents apply that intelligence across security workflows and actuators translate decisions into protection. Together, these layers create a continuous learning system that can understand risk, adapt to changing conditions and improve security outcomes over time.

While each layer provides important capabilities, the power of Project Perception comes from how they work together.

Security context built for AI

Effective reasoning requires more than raw signals. Agents need context.

Microsoft transforms its breadth of visibility, threat intelligence and security expertise into a security context that connects security data, knowledge and semantics across the digital estate. The result is a continuously updated representation of an organization’s assets, identities, relationships, risks and activities that gives agents a shared, near real-time, understanding of the environment they are helping to defend.

This shared understanding is foundational to how Project Perception operates. Rather than forcing agents to continuously gather, correlate and reconstruct context from raw signals, it provides them with immediate and token-efficient access to the information they need to reason over risk, prioritize actions and make decisions. By grounding every interaction in this rich security context, Project Perception improves the accuracy and consistency of reasoning while reducing the time, compute and cost required to operate at scale.

A multi-model architecture built for security

No single model will be optimal for every security task. Effective cyber defense requires applying the right model to the right problem at the right time.

For Project Perception, the right model is determined by the combination of quality, reliability, latency and cost. Rather than relying on a single model, Project Perception adopts a multi-model architecture that continuously selects the capabilities best suited to the task, optimizing for both effectiveness and economics. Because security is an always-on mission, sustainable economics are essential to operating protection at scale.

This approach is shaped by ongoing research, benchmarking and evaluation across frontier and specialized models. Our security researchers continuously assess models against real-world security workflows, enabling us to match each task with the model that delivers the best outcome. This allows customers to benefit from advances in AI without being tied to any single model.

Actuators — insights to actions

Security teams do not need more information. They need better outcomes.

That is why actuators are a critical part of the Cyber Stack. Project Perception is deeply integrated across Microsoft Security products, enabling agents to connect insights to actions. Organizations can continuously reduce risk rather than simply identify it, helping defenders strengthen security while remaining in control.

Built with safety first

Underpinning every layer of the Cyber Stack is a foundation of trust. Project Perception is built in alignment with Microsoft’s Responsible AI principles and inherits the security, compliance, governance and operational controls our customers already rely on. This ensures these capabilities are delivered with the same rigor, accountability and enterprise readiness that customers expect.

The future of security

Security has always been a race between attackers and defenders. AI changes the speed, scale and economics of that race. Defenders need systems that can continuously perceive, reason and act alongside them.

 Project Perception is how we begin to build that future.

To learn more about Microsoft Security solutions, visit our website. Bookmark the Security blog to keep up with our expert coverage on security matters. Also, follow us on LinkedIn (Microsoft Security) and X (@MSFTSecurity) for the latest news and updates on cybersecurity.

Microsoft’s AI Red Team Announces New Alliance: Enhancing AI Security Through Global AI Red Teaming

Hayete Gallot leads Microsoft’s work to help organizations operate securely in an AI-driven world. Her scope includes identity, threat protection, compliance and data security at global scale.

The post Rethinking security for the age of AI appeared first on Microsoft Security Blog.

Most AI safety testing still happens inside the walls of individual organizations. That has resulted in a fundamental disconnect: many of the highest-risk failure modes in modern AI systems require deep domain expertise, multilingual context, or regional understanding that no single internal team can fully replicate on its own. 

As frontier models become more capable, the attack surface expands with them. AI red teaming is no longer just about prompt injection or content safety edge cases. It increasingly involves security operations, misuse scenarios, multilingual harms, alignment failures, and domain-specific abuse patterns that can vary significantly across geographies and languages. 

Microsoft’s AI Red Team has observed that meaningful testing of advanced AI systems- and models similarly requires broader participation from researchers and practitioners who operate outside traditional corporate security boundaries. To address that gap, today we are announcing the External Red Team Alliance (EXTRA), a formalized global extension of Microsoft’s AI Red Team designed to support and encourage external expertise to advance AI safety and security testing.  We are proud to share we are funding the development of new AI safety assessments on six continents through unrestricted gifts. 

Building a global alliance

EXTRA is a two-part initiative focused on expanding AI safety research and strengthening external collaboration. 

The first component supports a global academic network focused on advancing AI safety and security research. Microsoft’s AI Red Team has provided unrestricted gifts to 18 university labs spanning six continents. The goal is intentionally broad: support researchers who are already investigating difficult, unresolved questions in AI safety and help them continue pushing that work forward independently. 

Some of the supporting institutions include: 

• Carnegie Mellon University Security and Privacy Institute (CyLab), United States 

• Georgetown University – Georgetown Security Lab (SecLab), United States 

• Harvard University Berkman Klein Center for Internet & Society (BKC), United States 

• Howard University Research Institute for Tactical Autonomy (RITA), United States 

• Indian Institute of Technology Madras – Centre for Responsible AI (CeRAI), India 

• Korea Advanced Institute of Science & Technology – KAIST Web Security & Privacy (WSP) Lab, Korea 

• New York University – NYU Alignment Research Group (ARG), United States 

• Northeastern University Network and Distributed Systems Security (NDS2) Lab, United States 

• University College London – UCL Information Security Research Group (UCL ISec), United Kingdom 

• University of Cagliari Pattern Recognition and Applications (PRA) Lab, Italy 

• University of California – Berkeley Risk and Security Lab; Center for Responsible, Decentralized Intelligence (CRDI), United States 

• University of Melbourne Artificial Intelligence Assurance Lab, Australia 

• University of Pretoria Data Science for Social Impact (DSFSI) Research Group, South Africa 

• University of São Paulo Center for Artificial Intelligence (C4AI), Brazil 

• University of Toronto CleverHans Lab, Canada 

• University of Washington Department of Human Centered Design & Engineering (HCDE), United States 

The second component of EXTRA focuses on operational collaboration. Microsoft is building a distributed network of specialists who can participate directly in red teaming highly specialized areas where deeper expertise is required. That includes researchers, practitioners, and regional experts who understand specific attack classes, languages, cultural contexts, or technical domains that internal teams may not fully cover alone. 

Beyond expanding participation, EXTRA is also intended to help advance the science of AI safety evaluation. By bringing together academic researchers, security practitioners, and domain experts from around the world, the initiative aims to contribute to the development of more robust methodologies and testing practices for increasingly capable AI systems. Today’s cybersecurity ecosystem depends on coordinated vulnerability research, responsible disclosure programs, academic inquiry, and global communities of independent security researchers who routinely identify risks that vendors alone would not find. Likewise, advancing AI safety will benefit from ongoing contributions from experts across institutions, disciplines, and geographies to identify emerging threats, strengthen safeguards, and improve evaluation practices. 

What the research focuses on

The research areas funded through EXTRA reflect several of the emerging areas Microsoft’s AI Red Team continues to encounter when evaluating advanced AI systems. 

Some universities are examining the cybersecurity implications of AI systems themselves — including how models can be attacked, manipulated, or abused in operational environments. Other labs are exploring the inverse problem: how AI systems can assist defenders and improve cyber operations. 

The structure of the program is intentional. The funding is unrestricted because the objective is not to direct research outcomes toward product requirements or predefined deliverables. The goal is to strengthen independent safety research capacity globally and create stronger long-term collaboration between academia and operational AI security teams. 

Why this matters

“Managing frontier AI risk requires more than internal safeguards. It requires continuous engagement with experts who understand how these systems behave across different technical, linguistic, and cultural contexts. EXTRA reflects Microsoft’s broader Frontier Governance Framework approach: combining rigorous internal governance with external support and collaboration to better identify, assess, and mitigate emerging risks as AI capabilities advance. By supporting independent research and building stronger connections with universities and specialists around the world, we are helping strengthen the broader ecosystem needed for trustworthy and secure AI development,” says Natasha Crampton, Chief Responsible AI Officer, Microsoft 

Governments too are increasingly focused on understanding the capabilities and security implications of frontier AI systems to strengthen resilience. But just as coordinated international research helped unlock the benefits of previous technological revolutions, diverse expertise from researchers and practitioners around the world is essential to identify emerging threats, improve defenses, and build greater confidence in AI systems.   

“Frontier AI is already shaping the future of both cybersecurity and national security. Understanding how these systems can be misused, and identifying risks before they become real-world threats, requires expertise that spans institutions, disciplines, and borders.” says Mike Yeh, VP & Deputy General Counsel, Customer Security and Trust, Microsoft 

AI red teaming is becoming more interdisciplinary, multilingual, and globally distributed. The expertise needed to identify meaningful failure modes increasingly lives across universities, independent research communities, and regional specialists. 

EXTRA reflects a practical shift in how AI security testing must operate going forward. External expertise is no longer supplemental to red teaming; in many cases, it is essential. 

Microsoft would like to thank these people for their important contributions with this project: Steph Ballard, Blake Bullwinkel, Nicholas Butts, Janelle Bryant, Kaja Ciglic, Hector de Rivoire, Eugenia Kim, Amanda Minnich, Shujaat Mirza, Jingxia Ni, Saphir Qi, Giorgio Severi, Hilary Solan, Hiwot Tesfaye, Sam Vaughan, Marguerita Wicklander, and the many teams at these schools around the world who helped coordinate 

The post Enhancing AI security through global AI red teaming appeared first on Microsoft Security Blog.

The second quarter of 2026 (April–June) was largely defined by the continuing downstream effects following Microsoft’s Digital Crimes Unit-led disruption efforts against the Tycoon2FA phishing-as-a-service (PhaaS) platform in March. Phishing volume linked to the platform fell 92% from pre-disruption averages, including QR code phishing and CAPTCHA-gated phishing both declining from their March highs. Despite ongoing efforts to rebuild operations, Tycoon2FA did not recover its previous scale or influence during Q2, and no single service emerged to replace the platform at comparable scale.

These trends reflect both the measurable impact that disruption operations can have on phishing ecosystems and the adaptability of threat actors as they diversify delivery channels. At the same time, Microsoft Threat Intelligence observed continued growth in Teams-based social engineering, particularly voice phishing (vishing), with weekly malicious call attempts reaching nearly ten times the mid-2025 baseline by the end of the quarter. This activity illustrates how threat actors continue to expand beyond email into trusted workplace communication platforms where communications may appear more trustworthy to users.

Microsoft detected approximately 7.6 billion email-based phishing threats throughout the quarter, with monthly volumes declining modestly from 2.7 billion in April to 2.4 billion in June. Credential phishing remained the dominant objective behind malicious payloads, while business email compromise (BEC) activity largely returned to historical norms after a brief, anomalous surge in April. Notable campaigns observed during the quarter also demonstrated how threat actors combine automation, trusted services, and multi-stage delivery chains to scale operations. These campaigns ranged from an automated BEC campaign that reached more than 67,000 users across 42,000 organizations in under three hours, to a multi-stage phishing campaign that used nested EML files, calendar invitations, and a Microsoft authentication redirect to deliver malware.

This blog provides a view of email threat activity across the second quarter of 2026, highlighting key trends in phishing techniques, payload delivery, and threat actor behavior observed by Microsoft Threat Intelligence. We examine shifts in QR code and CAPTCHA-gated phishing activity, malicious payload trends, BEC activity, the growth of Teams-based threats, and notable campaigns observed during the quarter. We also provide recommendations and Microsoft Defender detections to help organizations identify and mitigate evolving threats while prioritizing defensive measures.

Tycoon2FA Q2 disruption impact

The disruption operation that Microsoft’s Digital Crimes Unit launched against Tycoon2FA infrastructure in early March continued to produce measurable results throughout Q2 2026. After falling 15% in March and another 22% in April, Tycoon2FA-linked phishing volume dropped 74% in May to just 1.5 million messages, then fell another 20% in June to 1.2 million, by far the lowest monthly volumes observed in at least a year. For reference, the average monthly volume of phishing messages linked to Tycoon2FA during the second half of 2025 was 15.1 million. By the end of Q2, volumes were running at roughly 8% of that baseline, representing a 92% total decline since the disruption operation began.

Tycoon2FA’s influence across two primary phishing tactics, QR code lures and CAPTCHA-gated landing pages, also continued to decline throughout the quarter:

• CAPTCHA-gated phishing: Tycoon2FA’s share of CAPTCHA-gated phishing sites fell from 41% in March to 16% in April and 12% by June, down from a peak of 76% in December 2025.
• QR code phishing: The share of QR code campaigns redirecting to Tycoon2FA domains decreased from 20% in March to 17% in April and 14% by June, down from a peak of 33% in November 2025.

These declines indicate that the platform’s customer base has not migrated to replacement infrastructure at anything close to the scale they previously operated.

After being forced off Cloudflare, which had provided anti-analysis protection that made Tycoon2FA pages harder to scan and take down, the service continued to rely on infrastructure hosted on the .RU top-level domain (TLD), a shift that began in late March. More than 40% of newly observed Tycoon2FA domains used .RU registrations throughout Q2. While this reflects an ongoing effort to find replacement hosting, Tycoon2FA’s role in the phishing ecosystem has nonetheless been significantly diminished and the pace of recovery has been slow.

QR code phishing attacks

After peaking at 18.7 million attacks in March, the highest monthly volume in at least a year, QR code phishing declined for three consecutive months in Q2. Volume fell 7% in April to 17.4 million, then dropped more sharply in May (-38%) and June (-22%), closing the quarter at 8.3 million attacks. By June, QR code phishing had returned to levels last seen in mid-2025.

The delivery methods used in QR code attacks shifted notably during Q2. PDF attachments remained the dominant vehicle throughout, but their dominance weakened after April:

• PDF attachments peaked at 79% of QR code attacks in April before falling to 59% in May and 58% in June. By raw volume, malicious PDFs containing QR codes dropped more than 60% between April and June.
• DOC/DOCX attachments moved in the opposite direction, increasing 30% in May to account for 38% of QR code payloads, the highest share since December 2025. By June, DOC/DOCX payloads reached 40% of QR code attacks. This swap between PDF and DOC/DOCX dominance is a pattern that has recurred throughout the past year, as operators appear to rotate between delivery formats.
• Email-embedded QR codes, which had surged 336% in March and accounted for 5% of QR code attacks, effectively disappeared in Q2. This delivery method dropped to near-zero across all three months, leaving QR code phishing almost entirely an attachment-based tactic.

CAPTCHA-gated phishing tactics

After accumulating to nearly 12 million attacks in March, the highest monthly volume observed over the past year, CAPTCHA-gated phishing declined sharply throughout Q2. Volume fell 32% in April to 8.2 million, then dropped another 65% in May and 24% in June, closing the quarter at just 2.2 million attacks. Since the March peak, CAPTCHA-gated phishing has fallen more than 81%, reaching its lowest monthly volume in more than a year.

The rapid rotation of delivery methods that characterized Q1 continued into Q2, with no single payload type maintaining the top position for more than one or two months:

• PDF attachments surged to 63% of CAPTCHA-gated attacks in April, the highest single-payload share observed in the past year, after more than quadrupling in March. This dominance was short-lived, however. PDF volumes dropped 69% in May and another 70% in June, falling to just 22% of attacks by the end of the quarter.
• HTML attachments, which had been a major delivery vector through January (37% of attacks), declined sharply during Q2. After declining to 8% in April, HTML payloads fell to just 3% in May before recovering slightly to 5% in June, their lowest sustained share in at least a year.
• SVG files reached their lowest observed volume in April (5% of attacks) before rebounding to 12% in May and 26% in June. While still well below the levels seen when Tycoon2FA actively used SVG files, this gradual recovery bears monitoring.
• Email-embedded URLs reclaimed the top position in June for the first time since December 2025, accounting for 30% of CAPTCHA-gated attacks. This was more a function of every other delivery method declining in raw volume than a resurgence in URL-based delivery. The actual volume of URL-delivered CAPTCHA-gated phish in June was still far lower than most months over the past year.
• DOC/DOCX files declined from their March spike, falling steadily from 15% to 10% of attacks over the quarter.

Tycoon2FA’s continued decline was a significant factor in the overall volume reduction. The platform’s share of CAPTCHA-gated phishing fell from 41% in March to 16% in April, 18% in May, and 12% by June, down from a peak of 76% in December 2025. No single service has emerged to fill the gap at comparable scale, contributing to the sustained decline in CAPTCHA-gated phishing activity overall.

Malicious payloads

Credential phishing continued to dominate the malicious payload landscape throughout Q2, accounting for 94–96% of all payload-based attacks each month. These credential phishing payloads either linked users to phishing pages or locally loaded spoofed sign-in screens on a user’s device. Traditional malware delivery represented just 4–6% of payloads, consistent with its long-term decline.

HTML and PDF attachments remained the two most common malicious payload types across the quarter, together accounting for roughly 60–70% of all payload-based attacks each month:

• HTML attachments held the top position across all three months at 35–41% of attacks. After peaking in April, HTML payload volume declined 33% in May and another 17% in June.
• PDF attachments consistently ranked second at 24–31% of attacks. PDF volume was relatively stable in April before declining 41% in May and 4% in June.
• SVG files continued the decline that has tracked closely with Tycoon2FA’s diminishing activity. After peaking at 23% of malicious payloads in July 2025, SVG’s share fell to around 7% by Q2, consistent with SVG’s historical role as a preferred Tycoon2FA payload format.
• DOC/DOCX and ZIP/GZIP files oscillated without a clear directional trend. DOC/DOCX increased 26% in May before falling 17% in June, while ZIP/GZIP attachments declined 48% in April, rebounded 27% in May, then dropped 40% in June.
• ICS files (calendar invitations), while still a small share of overall payload volume (roughly 4%), nearly quadrupled in June (+277%). These attacks take advantage of the fact that calendar invitations are processed differently than standard email attachments and can inject malicious links into a user’s calendar without requiring an explicit open-and-click interaction.
• EXE files continued to decline, falling to their lowest monthly volume in June, reflecting the broader shift away from traditional malware delivery via email attachments.

Business email compromise

April 2026 produced the most anomalous BEC data point in more than a year: nearly 9 million attacks, a 121% increase from March and more than double any previous month. The spike was short-lived as volume fell 62% in May to 3.4 million and settled at 3.9 million in June, both figures consistent with the monthly baseline that had held throughout the prior year. The April surge appeared to be driven by a small number of high-volume campaigns rather than a fundamental escalation in BEC activity.

The composition of BEC attacks remained consistent throughout Q2. Generic outreach messages (like “Are you at your desk?”) accounted for 87–92% of initial contact emails each month, while explicit requests for specific financial transactions or documents represented just 3–8%. This pattern underscores that BEC operators overwhelmingly favor establishing conversational rapport with targets before making fraudulent requests, rather than leading with direct financial asks.

Within the smaller subset of explicit financial requests, the most notable trend was the near-disappearance of fake invoice payment requests:

• Invoice payment requests fell 67% in May and another 77% in June, reaching their lowest volume in more than a year. By June, invoice-themed BEC accounted for less than 0.4% of all attacks, down from around 3.6% in March.
• Payroll update requests declined moderately across the quarter, from roughly 4% of attacks in March to 2.3% by June.
• Gift card requests remained at roughly 1–4% of attacks, with no clear directional trend.

Microsoft Teams threats

While email remains the dominant initial access vector, threat actors increasingly abused Microsoft Teams during Q2 to deliver social engineering, phishing, and malware payloads. Unlike email, Teams traffic typically bypasses secure email gateways and benefits from the perceived legitimacy of a colleague-initiated chat, which can make lures particularly effective in this environment.

Teams-based phishing volume climbed steadily throughout Q2, with the average number of detected attacks rising 19% from March to April, holding roughly flat into May (+1%), then increasing another 10% into June. Financial and executive impersonation has remained largely absent from Teams-based attacks over the past several months.

The dominant lure theme remained technical support impersonation, with attackers posing as an employee’s information technology (IT) help desk, typically warning of an impending account lockout. However, the way attackers presented themselves continued to evolve:

• Display names shifted away from IT- or help desk-branded identities. For the second consecutive month, more than half (52%) of Teams-based phishing attacks in June used generic display names rather than obvious IT support impersonation.
• Attacker email addresses associated with these chats moved away from support-themed domains toward software-as-a-service (SaaS) terminology, scan/update language, and infrastructure keywords. This shift may align with the broader rise of ClickFix-style attacks adopting update-fix and similar themes.

Vishing through Teams showed the steepest growth of any threat category tracked in this report during Q2. Average weekly malicious call attempts rose 31% from April to May and another 27% into June, with the final two weeks of June recording the two highest weekly volumes on record. Since the beginning of 2026, weekly vishing attempts have increased roughly 80% and now run at nearly ten times the mid-2025 baseline. Attackers time these calls deliberately when targets are most likely to be online and active, with the heaviest activity falling between 14:00 and 20:00 UTC, Monday through Friday, with near-zero weekend activity. Notably, a growing share of these calls go unanswered, end quickly, or are rejected outright, partly reflecting Microsoft’s ongoing efforts to harden the Teams attack surface and improve protections against social engineering abuse.

Notable phishing campaigns

The following campaigns were observed during the quarter and highlight notable credential phishing, BEC, and malware delivery activity. For analysis of a separate code of conduct-themed credential phishing campaign observed in April of Q2, see Breaking the code: Multi-stage ‘code of conduct’ phishing campaign leads to AiTM token compromise.

Automated BEC campaign scales aging report and payroll diversion lures

On June 1, 2026, Microsoft Defender Research observed a high-volume BEC campaign that used automation to operate at scale. Over a send window of under three hours (14:08–16:52 UTC), the actor reached more than 67,000 users across more than 42,000 organizations, almost exclusively in the United States. Targeting spanned a broad range of industries rather than a single vertical, most notably retail and consumer goods (17%), technology and software (15%), and financial services (14%). The campaign ran two lures in succession from shared infrastructure: arequest impersonating sales executives to obtain aging report data and customer contact details, and a payroll diversion pretext impersonating the CEO or President to redirect salary payments to attacker-controlled bank accounts.

Delivery was fully scripted. The messages were generated programmatically using Python’s email.mime library, identifiable from its default MIME boundary format (===============[integer]==), and dispatched through the Amazon Simple Email Service (SES) API rather than a manual webmail interface, as indicated by the SES Feedback-ID and Message-ID formats. This allowed the actor to iterate through a recipient list and inject per-message variables (like spoofed executive display names, recipient addresses, and unique tracking identifiers) at volume. Messages were sent from a DomainKeys Identified Mail (DKIM)-configured Slovak domain (ecajovna[.]sk) through SES, so they passed Sender Policy Framework (SPF) and achieved DKIM alignment. Neither lure contained a malicious link or attachment; both relied on eliciting a reply to attacker-controlled mailboxes that mimicked legitimate providers (ilyff[.]com, j-gmails[.]com, x2mails[.]com).

Automation also extended to targeting and follow-up. The actor addressed generic role-based mailboxes (like “ar”, “accountsreceivable”, “hr”, “payroll”) rather than named individuals, reducing per-target effort. Each message embedded a 1×1 open-tracking pixel served from an Amazon SES engagement subdomain, with per-message identifiers that let the actor confirm which recipients opened the email and prioritize follow-up against those targets. The combination of scripted message generation, API-based bulk delivery, role-based targeting, and automated engagement tracking allowed a single actor to run a personalized, financially motivated BEC operation at a scale not practical to execute manually.

Staff update campaign with nested EML file and calendar invitation leads to BAT file dropper

Between June 14–15, 2026, Microsoft Defender Research observed a phishing campaign targeting more than 107,000 users across nearly 19,000 organizations, almost exclusively in the United States. The campaign targeted a broad range of industries rather than a single vertical, most notably financial services (17%), technology and software (14%), and retail and consumer goods (14%). Emails impersonated an internal “Internal Affairs – Financials & Staff Updates” function at the recipient’s own organization, with the display name and subject line both opening with the recipient’s organization name and closing with constant trailing text. The messages were sent from a Postfix host on 9i6pokerdepot[.]com routed through Barracuda’s outbound mail service, and DKIM passed cleanly for the sending domain.

The visible email body contained minimal content. One line told the reader to download the attached file for the meeting summary, followed by a confidentiality notice. Each message carried two attachments: a nested EML posing as a Teams archive recording, and an ICS calendar invite addressed to placeholder administrative accounts at the recipient’s domain. The nested EML’s file name retained an unfilled template token ( {{DATE2}} ), indicating a per-recipient templating tool.

When opened, the EML displayed a voicemail notification with a single action button. That button pointed to Microsoft’s OAuth sign-in endpoint at login.microsoftonline[.]com, with parameters that asked for a silent sign-in attempt against an Entra application that the attacker had registered as multi-tenant.

Because no active sign-in session could satisfy the silent request, Microsoft’s authentication service redirected the recipient to the destination the attacker had pre-registered on the application. That destination was a path on clickup-attachments[.]com, ClickUp’s public attachment host, and served a Windows batch file named Financial_report.bat. Because the link routed through Microsoft authentication infrastructure, both recipients and URL scanners saw a login.microsoftonline[.]com link.

The batch file ran a hidden PowerShell command that pulled installer.exe from pixeldrain[.]com, saved it under the user’s Temp directory, ran it with a silent flag, and deleted the dropper on exit. Rather than stealing credentials, the campaign ultimately resulted in silent malware execution on the user’s Windows device.

Mitigation and protection guidance

Microsoft recommends the following mitigations to reduce the impact of this threat. Check the recommendations card for the deployment status of monitored mitigations.

• Review the recommended settings for Exchange Online Protection and Microsoft Defender for Office 365 to ensure your organization has established essential defenses and knows how to monitor and respond to threat activity.
• Invest in user awareness training and phishing simulations. Attack simulation training in Microsoft Defender for Office 365, which also includes simulating phishing messages in Microsoft Teams, is one approach to running realistic attack scenarios in your organization.
• Enable Zero-hour auto purge (ZAP) in Defender for Office 365 to quarantine sent mail in response to newly acquired threat intelligence and retroactively neutralize malicious phishing, spam, or malware messages that have already been delivered to mailboxes.
• Responders could also manually check for and purge unwanted emails containing URLs and/or Subject fields that are similar, but not identical, to those of known bad messages. Investigate malicious email that was delivered in Microsoft 365 and use Threat Explorer to find and delete phishing emails.
• Turn on Safe Links and Safe Attachments in Microsoft Defender for Office 365.
• Enable network protection in Microsoft Defender for Endpoint.
• Encourage users to use Microsoft Edge and other web browsers that support Microsoft Defender SmartScreen, which identifies and blocks malicious websites, including phishing sites, scam sites, and sites that host malware.
• Enable password-less authentication methods (for example, Windows Hello, FIDO keys, or Microsoft Authenticator) for accounts that support password-less. For accounts that still require passwords, use authenticator apps like Microsoft Authenticator for MFA. Refer to this article for the different authentication methods and features.
  • Conditional access policies can also be scoped to strengthen privileged accounts with phishing resistant MFA.
• Configure automatic attack disruption in Microsoft Defender XDR. Automatic attack disruption is designed to contain attacks in progress, limit the impact on an organization’s assets, and provide more time for security teams to remediate the attack fully.

Microsoft Defender detections

Microsoft Defender customers can refer to the list of applicable detections below. Microsoft Defender coordinates detection, prevention, investigation, and response across endpoints, identities, email, apps to provide integrated protection against attacks like the threat discussed in this blog.

Microsoft Defender for Endpoint

The following alert might indicate threat activity associated with this threat. The alert, however, can be triggered by unrelated threat activity.

• Suspicious activity likely indicative of a connection to an adversary-in-the-middle (AiTM) phishing site

Microsoft Defender for Office 365

The following alerts might indicate threat activity associated with this threat. These alerts, however, can be triggered by unrelated threat activity.

• A potentially malicious URL click was detected
• A user clicked through to a potentially malicious URL
• Suspicious email sending patterns detected
• Email messages containing malicious URL removed after delivery
• Email messages removed after delivery
• Email reported by user as malware or phish

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following Threat Analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get the most up-to-date information about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide intelligence, protection information, and recommended actions to prevent, mitigate, or respond to associated threats found in customer environments.

Microsoft Defender XDR threat analytics

• Activity Profile: Email threat landscape, June 2026
• Activity Profile: Email threat landscape, May 2026
• Activity Profile: Email threat landscape, April 2026
• Tool Profile: Tycoon2FA
• Technique Profile: QR code phishing
• Technique Profile: ClickFix technique leverages clipboard to run malicious commands
• Threat Overview Profile: Business Email Compromise
• Threat Overview Profile: Adversary-in-the-middle credential phishing

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Indicators of compromise (IOCs)

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

To get notified about new publications and to join discussions on social media, follow us on LinkedIn, X (formerly Twitter), and Bluesky.

To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.

The post Email threat landscape: Q2 2026 trends and insights appeared first on Microsoft Security Blog.

Cyber incidents don’t wait—and effective response can’t either. In the age of AI where cyber incidents unfold at machine speed, having the right partnerships in place becomes paramount. While AI is expanding what’s possible, navigating this transformation can be challenging to do alone. That’s why our collaboration with AXA XL is so important—bringing Microsoft Defender Experts Cybersecurity Incident Response services directly to cyber insurance policyholders at the moment it matters most, helping organizations coordinate technical, business, and insurance decisions in parallel rather than in sequence.

This collaboration reflects Microsoft’s continued investment in building an incident response model designed for real-world conditions, where speed, trust, and alignment matter as much as technology.

In a live incident, security, executive, legal, and insurance teams are all acting at once. Without pre-established coordination, those parallel efforts can slow containment and increase risk. Our approach to incident response—and our work with AXA XL—starts by aligning those paths before a crisis begins.

For example, during a ransomware incident, security teams may be actively containing lateral movement while leadership evaluates operational impact, legal teams assess disclosure requirements, and insurers determine coverage pathways—all within the same window of time. When those decisions aren’t aligned, response slows and risk compounds.

Decades of supporting customers through high-stakes cyber incidents have reinforced a clear truth: effective incident response extends beyond technical execution. It requires coordination across teams and partners before the crisis hits. That experience continues to shape how we design Defender Experts Cybersecurity Incident Response—and how we work with partners like AXA XL.

Incident response must extend beyond technology

As a global insurance provider, AXA XL plays a critical role in helping organizations navigate cyber risk and response. Through this collaboration, AXA XL policyholders gain coordinated access to Microsoft’s dedicated incident response teams—combining threat containment, restoration, and recovery with insurance, legal, and regulatory workflows. By aligning AXA XL’s cyber insurance capabilities with Defender Experts Cybersecurity Incident Response, organizations benefit from a more integrated response model while gaining access to incident response teams informed by Microsoft Threat Intelligence and two decades of experience responding to some of the world’s most complex and consequential cyber incidents.

Previously, organizations often brought incident responders and insurers together in the middle of a crisis. With this collaboration, that relationship is already in place, reducing friction, delays, and uncertainty when time is most critical. AXA XL policyholders and Microsoft customers can now bring Defender Experts Cybersecurity Incident Response to the table the moment it matters—creating a clearer, more predictable path from detection to recovery. The outcome is not simply faster response, but confidence: knowing who to call, how response engages, and how recovery is operationalized before the next decision becomes urgent.

The threat of a cybersecurity incident has long been ‘not if, but when,’ and in the wake of AI, the ‘when’ may quickly become ‘how often.’ The risks organizations are tasked with preventing and overcoming relative to cybersecurity and data privacy are growing exponentially. Partnering with experts can make all the difference where resilience in the face of adversity may be your only saving grace. AXA XL’s strategic partnerships with  cyber incident response providers underscore our commitment to expertise, preparedness, and resilience. By drawing on a deep knowledge of internal expertise and external cyber specialists, we empower our insureds to respond swiftly and effectively to prevail when your number is up.”

—Gwenn Cujdik, Incident Response and Cyber Services Lead for North America, AXA XL

This collaboration reflects Microsoft’s continued investment in building an incident response model designed for real-world conditions, where speed, trust, and coordination matter as much as technology.

Incident response engineered for high-stakes moments—and the readiness behind them

What differentiates Microsoft Defender Experts Cybersecurity Incident Response is not only its deep technical expertise, but its direct connection to Microsoft engineering teams and Microsoft Threat Intelligence. Responders bring first-party insight into identity-based attacks, cloud intrusions, and enterprise compromise—insight informed directly by Microsoft’s global telemetry and security engineering teams. This connection enables responders to move quickly—from identifying the root cause of an attack to deploying mitigations informed by global threat signals. When combined with pre-aligned partners like AXA XL, that technical strength becomes even more impactful, allowing organizations to act decisively without navigating uncertainty during a crisis.

That same expertise extends beyond the moment of crisis. Delivered by the same frontline experts, Microsoft Defender Experts Cybersecurity Incident Response proactive services—incident response planning, assessments, simulations, and advisory engagements—help organizations build resilience, strengthening their ability to prevent, withstand, and recover from an incident.

These proactive engagements also help align internal teams and external partners before an incident occurs—clarifying roles, escalation paths, and decision-making processes. This preparation ensures that when an incident does occur, organizations are not starting from zero but executing against a coordinated plan. Resilience can mean the difference between containing an incident with minimal disruption and becoming the next headline.

Raising the bar for trusted incident response

The collaboration reinforces Microsoft’s long-standing commitment to delivering trusted cyber incident response services. It also underscores Microsoft’s intent to integrate directly into the cyber risk insurance ecosystem—working alongside insurers rather than operating adjacent to them during critical response moments. It reflects a shared belief that organizations deserve response capabilities that are proven, accessible, and designed to work together when it matters most.

As cyberthreats continue to evolve, Microsoft remains focused on strengthening this ecosystem—working with global insurance leaders like AXA XL to help organizations prepare for disruption, respond with confidence, and recover with resilience.

Learn more

To learn more about how our teams are working together, and how our collaboration with cyber insurance providers like AXA XL can help you strengthen your cyber resilience, visit the Microsoft Defender Experts Cybersecurity Incident Response webpage. 

To learn more about Microsoft Security solutions, visit our website. Bookmark the Security blog to keep up with our expert coverage on security matters. Also, follow us on LinkedIn (Microsoft Security) and X (@MSFTSecurity) for the latest news and updates on cybersecurity.

The post Real world incident response: Microsoft and AXA XL strengthen cyber resilience appeared first on Microsoft Security Blog.

Across the threat landscape, in this moment, one pattern sits at the center of the story: threat actors are following trust.

They are not only looking for vulnerable systems, but rather targeting the software, services, identities, tools, developer workflows, and AI systems that organizations already depend on.

A package can become a distribution path. A build pipeline can become an access path. A trusted tool can become or expand an attack surface. An AI agent with the wrong access can become a new way to reach code, data, or infrastructure.

While the surfaces may change, the goal for the majority of threat actors remains the same: find what is trusted, abuse it, and scale the impact.

At Black Hat USA 2026, Microsoft Security will walk through how we are seeing this shift unfold, how security teams can look for it earlier, and how threat intelligence, expert-led response, and security operations need to work together when campaigns move across software, identity, cloud, data, and AI systems.

On Wednesday, August 5, 2026, the day begins with David Weston’s keynote, The End of Rare: Defending When Offense Is Cheap, which looks at what defense requires when offensive capability becomes easier to access, automate, and scale. Later that afternoon, Aarti Borkar and Tanmay Ganacharya will resume the main stage for Poisoned at the Source: Inside the Hunt for Supply Chain Attacks, which offers a closer look at how Microsoft Threat Intelligence is hunting attacks across software ecosystems, developer workflows, and trusted services. This includes details into the ongoing attacks on npm (Node package manager). 

Together, these sessions frame the challenge security teams are facing now: when offensive capability becomes easier to scale, security teams need to understand the trust paths threat actors can abuse before those paths become open doors for attacks. 

At our booth, we’ll also showcase Microsoft Defender Experts Threat Intelligence, a new expert-led service delivering continuous, curated intelligence tailored to your organization, and Microsoft Defender Experts MDR, now extended with third-party and multicloud coverage.

From August 4 to 6, 2026, at Mandalay Bay in Las Vegas, you’ll find Microsoft Security on the Business Hall floor at booth #2144, and on Wednesday evening, join us at the Microsoft Security reception at Swingers at Mandalay Bay.

Weston on the future of defense 

At 9:15 AM PT on Wednesday, August 5, 2026, David Weston, CVP of Agentic Security, will examine what changes for security teams when offensive capability becomes easier to access, automate, and scale. 

The keynote sets up one of the central questions security leaders are facing now: how does the security operations center (SOC) and analysts adapt when threat actors can move faster, test more often, and reuse trusted paths across software, identity, cloud, and AI systems? Join the keynote Wednesday, August 5, 2026, then continue the conversation with Microsoft Security at booth #2144. 

Our latest intelligence (and response) on npm supply chain attacks

That same intelligence-to-action challenge is at the center of our main stage session at Black Hat. 

On Wednesday, August 5, 2026, from 2:30 PM PT to 3:00 PM PT, Aarti Borkar, Corporate Vice President (CVP), Microsoft Security, and Tanmay Ganacharya, Vice President of Microsoft Security Research and Threat Intelligence, will share intelligence and insights into the ongoing supply chain campaigns impacting all areas of the threat landscape. The talk, Poisoned at the Source: Inside the Hunt for Supply Chain Attacks, will walk through Microsoft Threat Intelligence’s investigations into the ongoing npm supply chain attacks targeting software ecosystems, developer workflows, trusted services, and how organizations are handling the challenges associated with npm packages.

Follow the research in the Black Hat Briefings

Microsoft Security researchers will also present peer-reviewed technical research in the Black Hat Briefings. These sessions go deep into cloud, mobile, and software supply chain defense.

GitHub Can Tell You’re Being Hacked. You’re Just Not Listening: Building EDR for GitHub from Its Own Event Stream

• Presented by Yossi Weizman, Principal Security Research Manager
• Wednesday, August 5, 2026, from 10:15 AM PT to 10:45 AM PT

One Click to System: Exploiting Bixby’s Trust Model for Full Device Compromise

• Presented by Dimitrios Valsamaras, Senior Security Researcher
• Wednesday, August 5, 2026, from 12:00 PM PT to 12:40 PM PT

Handle With Care: Chaining Azure Automation Flaws for Cross-Tenant Identity Takeover

• Presented by Shay Shavit, Senior Security Researcher
• Wednesday, August 5, 2026, from 4:30 PM PT to 5:10 PM PT

Check the official Black Hat schedule for final room assignments and any timing updates.

Go deeper in Microsoft sessions

Microsoft experts will also lead sessions that give you a closer look behind the scenes, including:

Mind the Gap: Turning Threat Intelligence into Decisive Action with Expert-Led Defense

• Presented by Wes Malaby, General Manager of Customer Success
• Wednesday, August 5, 2026, from 5:00 PM PT to 5:20 PM PT

Cyber Defense Showdown

• Presented by Fanta Kaba and special guest Jimmie Galaites
• Wednesday, August 5, 2026, from 5:00 PM PT to 5:20 PM PT

Agentic Security: What’s Next

• Presented by Naadia Sayed, Principal Product Manager
• Thursday, August 6, 2026, from 11:15 AM PT to 12:00 PM PT

These sessions extend the main stage story into practitioner decisions: how teams move from intelligence to action, how defenders test their judgment under pressure, and how AI and agents are changing security workflows.

Visit booth #2144 for research, community, and hands-on defense

This year we are transforming the Microsoft Security booth into a community center. Click here to jump to the full schedule.

If the keynote and main stage sessions frame the largest challenges across the threat landscape, booth #2144 is where you can directly explore the workflows behind it: threat intelligence, incident response, AI security, security operations, partner solutions, and hands-on practice.  

You will find:

Connection circles, ask-me-anythings (AMAs), meetups led by industry influencers, and lightning talks

Short-form conversations with practitioners and experts on threat intelligence, incident response, AI security, identity, data protection, and security operations. If you swing by when the expo area opens, we’ll also fuel you up so you can skip the food court.

Partner presence

At Black Hat 2026, the Microsoft booth will feature 13 partners from the Microsoft Intelligent Security Association (MISA) who will showcase solutions built with Microsoft Security technology. Security Insider Conversations will feature MISA partners Critical Start (August 5, 2026, at 3:30 PM PT) and Huntress (August 6, 2026, at 2:00 PM PT) alongside Microsoft Security experts. Additionally, thank you to our Microsoft Security VIP Mixer sponsors: Ascent Solutions, Avertium, Devicie, Huntress, Illumio, Maureen Data Systems, and Security Risk Advisors. 

Demo our latest innovations

Explore connected experiences across defending with AI, securing AI, strengthening posture for AI adoption, using security intelligence in investigations and response, working with trusted partners, and connecting with Microsoft Defender experts.

Exclusive swag (featuring a surprise guest)

Spend some time with us at the experience we built around the booth and you’ll earn tokens that can be exchanged for custom patches and hats (because security experts have to wear many hats). Your favorite paperclip may be among the patches. Maybe.

Decompress with mini golf

The biggest Microsoft Security community moment of the week is our reception at Swingers at Mandalay Bay, hosted by Aarti Borkar.

Join us Wednesday, August 5, 2026, from 6:00 PM PT to 9:00 PM PT for food, drinks, mini golf, partner activations, and time with the Microsoft Security team away from the show floor.

Come compare notes with peers, meet Microsoft researchers and responders, and connect with the broader Microsoft Security community.

Space is limited, so reserve your spot early.

Plan your week with Microsoft Security

You can find Microsoft Security at booth #2144 during Business Hall hours:

• Tuesday, August 4, 2026: 4:00 PM PT to 7:00 PM PT
• Wednesday, August 5, 2026: 9:00 AM PT to 6:00 PM PT
• Thursday, August 6, 2026: 9:00 AM PT to 4:00 PM PT

Stop by early to see the booth schedule, find upcoming AMAs and connection circles, and plan which live sessions and hands-on experiences you want to attend.

Skill up before and after Black Hat

You do not need to be in Las Vegas to take part in the broader Microsoft Security Black Hat experience.

The Microsoft Black Hat Skilling Challenge begins July 20, 2026, and will help defenders build hands-on skills across Microsoft Defender, Microsoft Sentinel, and Microsoft Security Copilot. Attendees can use the challenge to prepare before the event, then bring questions to on-site experts and community sessions. Remote participants can follow along through Microsoft Tech Community, AMAs, recaps, and post-event resources.

See you at hacker summer camp

Threat actors are adapting around the systems organizations already trust. Security teams need to understand those trust paths before they become attack paths.

At Black Hat USA 2026, Microsoft Security will bring the research, expert perspective, and hands-on experiences to help practitioners see where attacker behavior is moving and how defense can adapt.

Add Poisoned at the Source to your schedule. Visit us at booth #2144. Join the skilling challenge. And register for the Microsoft Security reception on Wednesday night.

Microsoft Security booth #2144 experiences and schedule

Tuesday, August 4, 2026

Wednesday, August 5, 2026

Thursday, August 6, 2026

To learn more about Microsoft Security solutions, visit our website. Bookmark the Security blog to keep up with our expert coverage on security matters. Also, follow us on LinkedIn (Microsoft Security) and X (@MSFTSecurity) for the latest news and updates on cybersecurity.

The post Microsoft at Black Hat USA 2026: Defending trust in the age of AI and supply chain attacks appeared first on Microsoft Security Blog.

From late April 2026 to mid-June 2026, Microsoft Defender Experts observed increased ACR Stealer activity across customer environments. These campaigns are successfully using ClickFix lures to steal browser credentials, authentication tokens, and sensitive documents from enterprise environments. Successful compromise can expose browser credentials, session tokens, authentication artifacts, and sensitive enterprise data, potentially enabling account compromise, unauthorized access to cloud resources, and follow-on intrusion activity. Security teams should prioritize monitoring for ClickFix lures, suspicious WebDAV activity, obfuscated PowerShell execution, and attempts to access browser credential stores.

ACR Stealer is an information-stealing malware family reportedly offered through a malware-as-a-service (MaaS) model and associated with the rebranding of Amatera Stealer. During this period, two campaigns stand out, together appearing frequently in reviewed recent intrusions. Both begin the same way, with a ClickFix social engineering technique that tricks targets into running the threat actor’s command, but the intrusion chains that follow diverge in how they deliver payloads, establish execution, and evade detection.

The first campaign relies on WebDAV-delivered payloads, staged PowerShell, Python-based loaders and persistence, and, in some intrusions, blockchain-backed dead-drop command-and-control (C2) resolution. The second campaign takes a more fileless route, using MSHTA, obfuscated PowerShell, and steganography-assisted in-memory execution. Despite these differences, both campaigns ultimately pursue the same goal: stealing browser-stored credentials and other sensitive data for exfiltration.

These two campaigns represent some of the most prevalent ACR Stealer delivery campaigns observed by Defender Experts; however, they do not represent the full range of delivery methods used by this malware family. Attribution to ACR Stealer is based on the observed behavior and post-exploitation tradecraft, corroborated by open-source intelligence on the infrastructure associated with this malware family. Additional campaigns, infrastructure patterns, and execution chains are likely active, and organizations should treat the indicators and techniques described here as representative.

Microsoft Defender for Endpoint can help surface both campaigns through behavioral coverage for living-off-the-land execution, suspicious WebDAV and MSHTA activity, obfuscated PowerShell, scheduled-task persistence, in-memory payload execution, and browser credential theft. In this blog, we analyze both campaigns in detail, including their delivery mechanisms, post-exploitation tradecraft, indicators of compromise, hunting opportunities, and guidance to help defenders detect and disrupt related activity in their environments.

Campaign 1: WebDAV-based ClickFix with Python loaders and blockchain C2

Initial access

In this campaign, a ClickFix prompt, likely delivered through malvertising or SEO-manipulated search results, instructs the target user to run a command that launches cmd.exe. The command subsequently invokes rundll32.exe to load a DLL from a remote WebDAV share accessed over HTTPS. The WebDAV path commonly uses a GUID-based directory structure and filenames designed to resemble legitimate resources (for example, google.ct), enabling the activity to blend with expected network traffic and evade casual inspection.

We observed three variants of the initial execution command:

Variant 1: Direct rundll32 invocation

Variant 2: pushd-Mounted WebDAV Share

Variant 3: Headless and obfuscated pushd execution

Variants 2 and 3 are notable for their use of pushd, which transparently maps the remote WebDAV share to a temporary local drive prior to execution. This technique allows threat actors to execute remotely hosted content through what appears to be a local path, simplifying payload execution while reducing user awareness. In the more advanced variant, threat actors further enhance stealth by launching commands through conhost.exe –headless, suppressing visible console windows, and employing environment variable obfuscation with delayed variable expansion to conceal critical execution components such as pushd, rundll32, and the remote host name. Combined with minimized or headless execution, these techniques reduce user visibility, complicate static analysis and detection, and enable the infection chain to execute with minimal indication to the victim.

Execution, persistence, and evasion through process masquerading

Once rundll32.exe loads the DLL retrieved from the remote server, the malware establishes communication with threat actor-controlled infrastructure and executes a heavily obfuscated PowerShell script. The script employs excessive arithmetic no-ops, dead loops, fake control flow, and randomized variable names to hinder static analysis and evade signature-based detection.

The PowerShell script subsequently deploys another stage that functions as both a malware installer and a persistence mechanism. It:

• Downloads a ZIP-packaged payload from a remote server and extracts it into a deceptive directory under %LocalAppData%\Temp (for example, LogiOptionsPlus).
• Launches a Python script using a bundled pythonw.exe instance to avoid displaying a console window.
• Removes previous deployments and terminates running instances before installation, effectively operating as an updater.
• Establishes persistence through a hidden scheduled task disguised as a legitimate software update, ensuring execution at user sign-in.
• Copies timestamps from a trusted Windows binary (notepad.exe) to the deployed files and clears PowerShell command history to reduce forensic visibility.

Python loader launching the stealer

The Python component serves as a heavily obfuscated loader designed to conceal its true functionality until runtime. It employs multiple layers of defense against static analysis, including dynamic API resolution, encoded string reconstruction, junk-data removal, character shifting, string reversal, Base64 decoding, and zlib decompression. These techniques ensure that the embedded payload remains unreadable in its static form and is reconstructed only during execution, significantly hindering signature-based detection and automated analysis.

Once decoded, the final-stage payload functions as an in-memory shellcode loader. It extracts an archive file masquerading as a legitimate application installer, reads a file from the archive, and injects the payload into a system process. The loader allocates executable memory using VirtualAlloc, copies the payload into the allocated memory region, and transfers execution through the Windows Fiber API (ConvertThreadToFiber, CreateFiber, and SwitchToFiber). This technique facilitates stealthy in-memory execution while minimizing artifacts written to disk.

Credential theft and data staging for exfiltration

The malware (injected code) aggressively harvests information from browser credential stores. It invokes Windows Data Protection API (DPAPI) routines to decrypt locally stored browser passwords, cookies, and authentication tokens. It also enumerates files across the system, targeting PDFs, Microsoft 365 documents, and data stored in enterprise-synchronized directories such as OneDrive and SharePoint. The collected data is subsequently archived, indicating preparation for exfiltration.

Blockchain dead-drop C2 resolution

A notable variation in this campaign is the use of blockchain services for C2 resolution, utilizing a technique known as EtherHiding. While most intrusions rely on more conventional C2 mechanisms, a subset deploys an additional secondary Python loader that leverages blockchain services as dead-drop resolvers. When this loader executes, it has been observed communicating with public blockchain RPC endpoints and third-party Web3 node infrastructure, likely querying data stored on a decentralized public ledger to retrieve follow-up payloads or a C2 address.

By externalizing C2 information to the blockchain, operators could dynamically update infrastructure without modifying or redeploying the malware, significantly complicating detection and takedown efforts. This behavior was observed across both variants of the campaign.

Campaign 2: MSHTA-initiated PowerShell chain with steganographic payload delivery

The second campaign takes a distinctly different approach to both delivery and execution. Where Campaign 1 relies on disk-based artifacts (Python runtime, scheduled tasks, and masquerading binaries), this campaign achieves its objectives almost entirely through fileless, in-memory execution, making it harder to detect through file-based scanning and forensic analysis.

Initial access through MSHTA and ClickFix

The execution chain begins when the victim, directed through malvertising or SEO-manipulated search results, encounters a ClickFix prompt that triggers a command spawning MSHTA to fetch and execute remote HTA content from an threat actor-controlled domain. The embedded VBScript loader abuses COM objects to decode and execute encoded PowerShell content.

PowerShell downloader and obfuscation

The decoded PowerShell stage employs obfuscation techniques similar to those seen in Campaign 1: randomized variable names, arithmetic no-op operations, dead loops, misleading control flow, and custom encryption routines. Prior to contacting its next-stage infrastructure, the malware generates a victim-specific identifier and disables certificate validation. The retrieved content is executed directly in memory.

Steganography-based payload delivery

A notable technique in this campaign is the use of steganography to conceal malicious content inside a publicly hosted image. Instead of downloading a secondary script (as in Campaign 1), the malware retrieves a JPEG image from an image-hosting service.

Analysis of the script revealed custom routines that extract an embedded payload from image pixels, decrypt and decompress it, and execute it entirely in memory. The payload dynamically resolves APIs such as LoadLibrary, GetProcAddress, VirtualAlloc, CreateThread, and WaitForSingleObject at runtime to perform reflective shellcode execution. By combining steganography with in-memory execution, the malware minimizes on-disk artifacts and complicates both detection and analysis.

Credential theft, data collection, and exfiltration

Following execution, the malware accesses credential stores belonging to Chromium-based browsers, including Google Chrome and Microsoft Edge, specifically the Login Data and Web Data databases, alongside Windows DPAPI decryption activity. This behavior indicates attempts to recover stored browser credentials, session cookies, authentication tokens, and other sensitive user information.

The malware also enumerates and accesses multiple high-value PDF documents across Desktop and Downloads locations, suggesting targeted collection of potentially sensitive files. The combination of browser credential harvesting and systematic document access points to an information-stealing objective focused on staging credentials and valuable user data for exfiltration.

Mitigation and protection guidance

Microsoft recommends the following mitigations to reduce the impact of ClickFix lures, script-based payload delivery, credential theft, and post-compromise activity.

• Educate users to recognize ClickFix-style prompts, fake verification checks, and paste-and-run instructions as malicious, especially when they invoke command interpreters or script hosts such as cmd.exe, PowerShell, rundll32.exe, or mshta.exe.
• Reduce exposure to malvertising, SEO poisoning, and other web-based delivery chains by enforcing web filtering, blocking low-reputation or newly observed domains, and limiting access to remote content sources that are not required for business operations.
• Use application control and attack surface reduction rules to restrict PowerShell, Python, mshta.exe, rundll32.exe, and similar tools from launching untrusted or internet-delivered content, particularly from user-writable directories such as Downloads, Temp, and %LocalAppData%.
• Monitor for suspicious persistence and defense-evasion behavior, including scheduled tasks masquerading as software updates, timestomping, PowerShell history clearing, and execution chains that progress from remote content retrieval into PowerShell, Python, or shellcode-loading behavior.
• Investigate abnormal access to Chromium-based browser databases, DPAPI-related decryption activity, staged collection of Microsoft 365 documents or PDFs, and compression activity that may indicate credential theft or data staging for exfiltration.
• If compromise is suspected, isolate affected devices, rotate exposed credentials, revoke potentially compromised tokens, review persistence mechanisms, and investigate outbound connections to remote shares, image-hosting services, or other infrastructure used to resolve or retrieve follow-on payloads.
• Harden endpoints against credential theft by reducing reliance on browser-stored credentials, enforcing multifactor authentication and conditional access, and reviewing how privileged accounts access sensitive applications and synchronized enterprise data.
• Turn on cloud-delivered protection and behavior-based detections to help identify rapidly evolving threats, suspicious script execution, in-memory payload delivery, abuse of browser credential stores, and unusual child-process activity.
• Run endpoint detection and response (EDR) in block mode and enable automated investigation and remediation so post-breach detections are contained, and malicious artifacts can be removed with minimal delay.
• Harden PowerShell by enforcing appropriate execution policies, turning on script block logging, module logging, and transcription, and monitoring this telemetry for signs of malicious script activity.
• Turn on tamper protection and prevent local administrators from weakening antivirus protection through local policy or exclusion changes.

Microsoft Defender XDR detections

Microsoft Defender XDR customers can refer to the list of applicable detections below. Microsoft Defender XDR coordinates detection, prevention, investigation, and response across endpoints, identities, email, and apps to provide integrated protection against attacks like the threat discussed in this blog. 

Microsoft Security Copilot

Microsoft Security Copilot is embedded in Microsoft Defender and provides security teams with AI-powered capabilities to summarize incidents, analyze files and scripts, summarize identities, use guided responses, and generate device summaries, hunting queries, and incident reports.

Customers can also deploy AI agents, including the following Microsoft Security Copilot agents, to perform security tasks efficiently:

• Threat Intelligence Briefing agent
• Phishing Triage agent
• Threat Hunting agent
• Dynamic Threat Detection agent

Security Copilot is also available as a standalone experience where customers can perform specific security-related tasks, such as incident investigation, user analysis, and vulnerability impact assessment. In addition, Security Copilot offers developer scenarios that allow customers to build, test, publish, and integrate AI agents and plugins to meet unique security needs.

Threat intelligence reports

Microsoft Defender XDR customers can use the following threat analytics reports in the Defender portal (requires license for at least one Defender XDR product) to get current information available in the Defender portal about the threat actor, malicious activity, and techniques discussed in this blog. These reports provide the intelligence, protection information, and recommended actions to help prevent, mitigate, or respond to associated threats found in customer environments:

• Amatera Stealer: Rebranded ACR Stealer With Improved Evasion, Sophistication
• Double Trouble: Latrodectus and ACR Stealer observed spreading via Google Authenticator Phishing Site

Microsoft Security Copilot customers can also use the Microsoft Security Copilot integration in Microsoft Defender Threat Intelligence, either in the Security Copilot standalone portal or in the embedded experience in the Microsoft Defender portal to get more information about this threat actor.

Advanced hunting queries

Microsoft Defender XDR customers can run the following advance hunting queries to find related activity in their networks:

Run the query below to identify suspicious commands executed through ClickFix-based activity observed while delivering this stealer

DeviceRegistryEvents
| where RegistryKey has "RunMRU"
| where (RegistryValueData has_all ("rundll32", "@ssl", " /c ", " start ") and (RegistryValueData matches regex @"\\\\[^\\]+@ssl\\[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}\\\w+\.\w+,#1" or
RegistryValueData matches regex @"(?i)pushd \\\\[^\\]+@ssl\\[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12} ")) 
or RegistryValueData has_all ("@ssl", " /c ", "conhost --headless ") and RegistryValueData contains "rundll32"

Run the query below to identify scheduled task creation used for persistence by a malicious PowerShell script

DeviceProcessEvents
| where InitiatingProcessFileName =~ "powershell.exe"
| where InitiatingProcessCommandLine has_all ("-Command", "powershell")
| where ProcessCommandLine has_all ("schtasks", " /run /tn ", " Autoupdate ") and ProcessCommandLine matches regex "[0-9]{8}"

Run the query below to identify suspicious MSHTA launch through PowerShell

DeviceProcessEvents
| where InitiatingProcessParentFileName has "explorer.exe"
| where InitiatingProcessFileName =~ "powershell.exe" and InitiatingProcessCommandLine in~ ('"PowerShell.exe" ', '"PowerShell.exe"')
| where ProcessCommandLine has_all ('"mshta.exe" https://') and ProcessCommandLine matches regex "/[0-9]{7}"

MITRE ATT&CK techniques observed

The following mapping summarizes the primary tactics and techniques observed across the two ACR Stealer intrusion chains. The mapping is intended to help defenders align observed behaviors with existing detection coverage, response playbooks, and hunting priorities.

Indicators of compromise (IOC)

References

• Intelligence Insights: May 2026 | Red Canary
• Possible ACR Stealer From Page Impersonating Claude

Learn more

For the latest security research from the Microsoft Threat Intelligence community, check out the Microsoft Threat Intelligence Blog.

To get notified about new publications and to join discussions on social media, follow us on LinkedIn, X (formerly Twitter), and Bluesky.

To hear stories and insights from the Microsoft Threat Intelligence community about the ever-evolving threat landscape, listen to the Microsoft Threat Intelligence podcast.

Review our documentation to learn more about our real-time protection capabilities and see how to enable them within your organization.   

• Evaluate your AI readiness with our latest Zero Trust for AI workshop.
• Microsoft 365 Copilot AI security documentation 
• How Microsoft discovers and mitigates evolving attacks against AI guardrails 
• Learn more about securing Copilot Studio agents with Microsoft Defender  

The post ACR Stealer: Two observed intrusion chains amid increased threat activity appeared first on Microsoft Security Blog.

AI agents aren’t only smarter API callers. They plan, chain actions across systems, and invoke tools in sequences while no single human explicitly approves each step. The architectural reality may introduce identity and authorization challenges that organizations are still evolving to address.

When an agent operates without a managed identity and least-privilege role-based access controls (RBAC), it can access or modify sensitive data beyond intended permissions if controls are not properly configured. Since agents can operate across multiple systems within a single workflow, a misconfigured permission may increase the potential impact compared to traditional service account scenarios, depending on how the system is configured and scoped. Organizations are deploying agentic capabilities (multi-step automation, delegated actions, tool use) faster than their identity and authorization models are evolving to safely constrain them.  

The resulting exposure can be significant and may include risks such as unauthorized data access, unintended writes or deletions, and potential privilege escalation arising from overly broad role assignments. In some cases, these conditions can also contribute to gaps in auditability, which may make cyberattack detection, incident response, and regulatory inquiries more complex than necessary.

The right mental model is to treat every agent as a first-class principal: give it a lifecycle-managed identity, assign explicit roles, scope its permissions tightly, and scope tool usage to a preconfigured tools manifest or configuration. 

Real-world scenarios

The risk can occur in real-world implementations. Consider a common pattern: a team provisions an agent with a broad “Reader” role because it’s quick and the initial use case seems read-only. Then the workflow expands to include fixing issues it finds, and suddenly the agent needs write access too. Rather than rethinking the role design, teams grant something broader than intended and move on.

The scope creep is quiet, incremental, and rarely revisited. A related problem emerges when agents work across multiple tools. An agent with access to email, files, a ticketing system, and a code repository may look low-risk at each individual integration, but the combination lets it correlate data across systems and take actions no one explicitly authorized as a whole. Combined access across systems may result in broader effective permissions than evaluated individually.

Underneath both scenarios is a question that teams consistently fail to answer cleanly: is the agent acting under its own identity, a delegated user scope, or some mix of both? That ambiguity matters because it determines who’s accountable when something goes wrong, and what approvals were actually required.

When the answer isn’t documented and enforced upfront, it shows up later in the worst possible context: an incident where logs might capture what tool was called but can’t answer key questions such as: who authorized the action, under what role, or whether it was within intended scope. Sensitive data may be retrieved or summarized beyond its intended audiences if controls are not properly scoped.

An agent helpfully automates a remediation step and modifies or deletes something it shouldn’t have. Then the investigation stalls not because logs are missing, but because the identity model was never coherent enough to make them meaningful. This leaves organizations in the firefighting mood to resolve and solve questions their leadership cannot fully answer to customers, press, or auditors.

Best Practices: Identity + RBAC + Scope + Safe Tool Binding

For best practices in designing agentic identity and authorization, implementing multiple controls is intended to help reduce the potential impact of agent actions when configured and applied appropriately, while helping make privilege decisions explicit and supporting accountability in the event of unexpected or unintended outcomes.

Recommended practices for teams are generally to establish and document:

(1) a unique, dedicated agent principal with a named owner and an explicit purpose

(2) least-privilege, task-based roles that are scoped to the specific resources and data the agent needs

(3) Controlled tool access intended to limit the agent to approved actions

(4) end-to-end auditability so you can answer “what happened, under what authority, and what changed?” quickly.

In practice, the time-limited aspect should typically apply to entitlements (role activation, tokens, or approvals) rather than trying to create a new identity for every task. Most real-world deployments keep the agent identity stable for lifecycle management, while using just-in-time (JIT) elevation to grant narrowly scoped privileges only for the duration of a specific workflow.

Start by making the agent afirst-class principal. Create a dedicated agent identity (not a shared secret or reused service account), document its purpose statement (“what it is allowed to do and why”), and assign clear human ownership for approvals and incident response.

Build in lifecycle management from day one: onboarding checks, credential rotation, suspension/decommissioning procedures, and a fast shutdown mechanism that actually invalidates credentials and tokens. Then design role-based access controls (RBAC) around discrete tasks, not teams or org charts.

Model roles that match the smallest meaningful units of work, such as “Read-only knowledge retrieval,” “Summarize labeled documents,” “Create a draft ticket.” Avoid bundling unrelated permissions to reduce operational friction. When the workflow includes both evidence gathering and remediation, separate duties: use different roles (or different tools) for read versus write, and gate high-impact actions like delete, export, or privilege changes behind step-up approvals.

Scope everything and do it multiple times. Constrain permissions by resource boundary (tenant/subscription/workspace/site), by data boundary (collection, label, sensitivity), and by operation boundary (read/write/export/admin).  

The goal is to help make the where and what of access as explicit as the who. Pair this with safe tool binding by exposing a curated and approved set of tools/actions to the agent, and require explicit allowlists for high-impact operations.

This is where JIT for agents can help manage privilege exposure when implemented appropriately, such as, keep the baseline role minimal, use time-limited entitlements (temporary role activation, short-lived tokens, or per-action approvals) when the workflow genuinely requires higher privilege—and automatically drop back to the baseline when the workflow completes.

Finally, design systems to verify explicitly at every step whenever feasible. Downstream tools and services must re-check claims, roles, and scope on each call rather than trusting the orchestrator implicitly; otherwise, the “weakest link” becomes any integration that assumes upstream validation is sufficient.

Consider incorporating accountability controls as a core product feature, not an afterthought. Instrument agent actions end-to-end so logs capture the agent identity, role used, effective scope, resource accessed, action taken, “on behalf of” user (if applicable), timestamps, and correlation IDs that stitch together orchestrator → tool call → downstream system.

Without those fields, teams can’t reliably reconstruct intent or containment boundaries during an incident. Build and test revocation and recovery paths the same way you test feature reliability: practice disabling the agent identity, rotating credentials, and executing rollback/compensating actions for common failure cases (e.g., bulk ticket creation gone wrong, unintended writes, or export attempts). Operationalize governance with regular access reviews, removal of stale permissions, and mandatory re-approval when workflows change materially. And don’t stop at individual roles—deploy tools and processes that analyze aggregate permissions, because the real risk often emerges when multiple “reasonable” roles combine to enable a high-impact chain of actions.

Common pitfalls tend to undermine these controls in predictable ways. The fastest way to create long-term risk is granting broad Owner/Admin roles to unblock a pilot, then never coming back to refactor permissions once the workflow “works.” Shared secrets across multiple agents erase accountability and make revocation slow and incomplete.

Relying on prompts or “the agent will only do X” narratives instead of hard authorization boundaries invites prompt injection and workflow drift. Without the underlying tool invocations, scopes, and downstream authorization decisions, logging only the LLM response creates an audit trail that looks present but is useless for forensics.

Temporary access that lacks an expiry mechanism becomes permanent access in practice. Teams can avoid these anti-patterns by defaulting to task-based roles, enforcing explicit scopes and tool allowlists, using JIT time-limited entitlements for elevation, re-checking authorization in every downstream system, and treating access review and revocation testing as required operational hygiene—not optional maturity work.

Looking Ahead

Agents are quickly moving from helpers to autonomous actors across email, files, tickets, and cloud resources; driving tighter coupling between identity governance, fine-grained authorization, and tool/action policy.

In the next 30–90 days, inventory your agent identities, remove broad roles, introduce task-scoped RBAC, and require safe tool binding plus end-to-end audit logs (with monitoring) before expanding deployments—especially for cross-tenant/guest agents, B2C agents, and agent ecosystems.

Read the Pattern & Practice (PnP): Least Privilege for Agents and use it as a checklist to close the gaps that most reduce impact: ownership, scope, tool allowlists, and fast revocation. 

The post Least privilege for AI agents: Identity, access, and tool binding appeared first on Microsoft Security Blog.