For more than two decades now, setting up a home router has meant going through the same old routine: pick a Wi-Fi band, name your network, choose a security type, and set a password. After you type in your network name, you often see an option next to it to hide the network name — sometimes labeled hide SSID, or simply hidden or closed network. If you choose this option, the network you create won’t show up automatically in the list of available Wi-Fi networks on any smartphone, computer, or smart-home device — you need to type in the correct network name by hand. Only then will the device be able to find that network and connect to it. At first glance, hiding your wireless network’s name might seem like a smart precaution: keeping neighbors or passersby from hacking into your Wi-Fi since they simply can’t see it. But in fact things work differently: all your devices will give away the hidden network — and not just at home either.

How devices connect to Wi-Fi

Every Wi-Fi access point broadcasts a short data packet roughly 10 times a second so your smartphone or computer can show you a list of nearby networks’ names, like JohnWiFi, TommyNet, CafeDeArts_Guest, or other, creative variants. This packet contains (i) the network’s name (Service Set Identifier, or SSID), (ii) a unique identifier for the access point (Basic Service Set Identifier, or BSSID), and (iii) details about the radio channel the network uses. This info helps devices (i) pick the best network to connect to, and (ii) automatically join networks they already know; accordingly, none of the data in that packet is encrypted. Hidden networks also broadcast these advertising packets; they just leave the SSID field blank. This method of finding networks is called passive because a Wi-Fi client, like, say, your smartphone, just needs to listen to the airwaves to spot nearby access points.

On top of that, the client can scan for Wi-Fi networks on its own, which is known as active discovery. Your smartphone or computer is constantly broadcasting the names of Wi-Fi networks it knows and would like to connect to. If one of those networks happens to be nearby, the access point answers back, and the connection is made.

Active discovery can sometimes help save your smartphone’s battery, and it’s indispensable when you’re working with hidden networks. Discovering a hidden network and connecting to it becomes a two-step process. First, the smartphone “hears” that there’s a Wi-Fi access point nearby with a hidden network name. It then tries to reach that network by broadcasting the names (SSIDs) it already knows — either hidden networks it’s connected to before, or the name the user typed in when first connecting to a hidden network. If the name matches, the router responds, and the connection goes through.

A hidden network name (SSID) doesn’t actually hide your Wi-Fi network

The regular list of available Wi-Fi networks on your smartphone or computer won’t show networks that don’t broadcast a public SSID. But any specialized Wi-Fi scanning software can spot them easily — it just won’t show their names. And hidden networks are still easy to identify and tell apart thanks to each router’s unique BSSID.

So hiding a Wi-Fi network’s name doesn’t make it truly invisible, and it won’t protect you from cybercriminals. It’s worth noting that any large-scale analysis, such as mapping the geographic locations of Wi-Fi networks, relies on BSSIDs, not SSIDs. Besides the huge databases kept by Apple and Google, there are public access-point-mapping projects too, like WiGLE.

If someone wants to break into a network at a specific location, specialized software lets them find out its SSID just by waiting for one of the legitimate clients to connect and listening in on the active discovery session. From there, they can connect to that Wi-Fi network — provided it uses a weak enough security protocol.

Your devices leak hidden Wi-Fi network names and personal data

The main drawback of a hidden SSID is that smartphones and computers have to broadcast it before they can connect to the wireless network. And they do this everywhere — not just near the specific access point in question. As soon as any network with a hidden name shows up within signal range, the client attempts to connect, and during that attempt it broadcasts the names of every hidden network it knows. And this broadcast isn’t encrypted, which means anyone nearby can pick up the data being transmitted.

In 2021, researchers at the University of Hamburg ran an experiment collecting radio signal data on a busy street. In just three one-hour listening sessions, they gathered 252 000 Wi-Fi connection requests from passersby’s smartphones. Of those, 23% contained the SSID of a network the smartphone would have preferred to connect to.

And that’s where a factor few people think about comes into play: the network’s name itself. Twelve percent of the SSIDs found were long numeric strings that looked a lot like passwords. So, once someone knows the SSID and BSSID, they can look up the BSSID in a service like WiGLE and find the access point’s real-world address. Once there, an attacker can try to use such a string as both the SSID and the password to connect — with a good chance of success. The researchers’ sample also included 106 SSIDs containing a first and/or last name, 92 SSIDs that pointed to a home address, and three that revealed an email address.

Given all this, it’s no surprise that Apple and Asus recommend against using the hidden SSID feature.

Other drawbacks of hiding your Wi-Fi network

Beyond the data leak issues, hidden SSID technology — a holdover from early Wi-Fi versions — also hurts the performance of modern versions of the radio protocol. In the 6GHz band, searching for a hidden Wi-Fi network across 59 possible channels becomes noisy and power-hungry: the client has to run through every option and send a lot of requests. As a result, performance drops for all nearby Wi-Fi networks in the 6GHz band, and the client itself burns through battery power sending out all those requests.

Asus also points out that Windows devices may tend to connect to visible networks first — even if a network with a hidden SSID is available and marked as preferred.

When a hidden SSID actually makes sense

There aren’t many scenarios where hiding your network name is genuinely useful. For example, if a router is meant for a small group of people but is installed in a very crowded location, a hidden SSID can cut down on the number of connection attempts and ease the load on the router. But keep in mind that this boosts performance, not security — and only slightly at that.

Another similar case is a technical Wi-Fi network for a limited number of fixed devices — like a network of security cameras or smart home gadgets. These devices always stay in the same place, so whenever they try to connect to their assigned Wi-Fi, they find it right away, and no data leaks out — unless an attacker is actually listening in on the radio signal near the router. At the same time, outsiders are less likely to try connecting to such a network.

How to make your Wi-Fi more secure

To protect your Wi-Fi network from wireless hackers, don’t hide the SSID: instead, use the modern WPA3 security protocol along with a long password. Attackers can intercept data over the air and then try to crack the password with brute force, so a strong Wi-Fi password should be at least 20 characters long. The easiest way to generate and store such long, hard-to-crack passwords is with a password manager that syncs across your devices; that way they’re always at hand — no matter which gadget you’re using.

If some of your older devices don’t support WPA3, it’s fine to use WPA2 with protected management frames (PMF) turned on, which guard against many types of attacks on Wi-Fi networks.

You should also make sure Wi-Fi Protected Setup (WPS) is turned off, since it essentially replaces your password with an easy-to-guess PIN code.

To quickly spot unknown devices connected to your Wi-Fi network, use Smart Home Monitor in Kaspersky Premium.

As for the network name, instead of hiding it, pick one that doesn’t reveal your name, address, or any other personal details. It’s also worth avoiding default network names like ISPName-XXXX or dlink, but for a different reason: generic names like these can confuse you and your guests alike. If you don’t want your access point to show up on Wi-Fi geolocation maps from Apple, Google, and other providers, you can add the suffix _nomap to the end of your network name, but there’s no guarantee it will actually work.

Apart from protecting your Wi-Fi, make sure your router is configured securely overall. First and foremost, that means giving it a long, unique admin password, and keeping it updated with the manufacturer’s latest firmware. And if you have a bit more time, you could even boost your Wi-Fi performance.

How Wi-Fi networks get hacked, and how to protect them:

• How to find a person and recognize their pose using Wi-Fi
• Is your printer informing on you to the police?
• Wi-Fi hacking using PMKID interception
• How to secure your smart home
• Securing home security

In 2026, the owner of an ordinary home router, smart TV, or TV box is a prime target for cybercriminals. These devices are readily recruited into botnets and residential proxy networks, which we’ve covered before.

Criminals “sublease” the infected device by letting outsiders pay to visit any website from the victim’s IP address, so it looks like the device’s owner is doing it. The service is in demand across all kinds of shady schemes: from ad fraud and spam campaigns to password bruteforcing and account hacking. In our previous post, we described how home routers get recruited into these proxy networks; today we take a look at an even more vulnerable, and equally ubiquitous category of devices: smart TVs and TV boxes.

These appeal to criminals for two reasons. First, unlike computers and smartphones, TVs are almost always plugged into the power and have a fast internet connection. A dark screen doesn’t mean the device is switched off. On top of that, the limited user interface and monitoring tools mean suspicious background processes can easily slip unnoticed past users.

The threat is evolving and growing more aggressive. A recent study found that once proxyware turns up on a set-top box, the risks to its owner go well beyond having their traffic siphoned off.

Anatomy of the infection

The researchers focused on a popular TV box by SuperBox, which we already covered earlier in the post Is your TV box renting out your network?

SuperBox’s marketing leans heavily on the promise of providing thousands of TV channels, with no subscription or monthly fees. But out of the box, the device can’t actually do anything of the sort. To get access to pirated content, you need to install the brand’s proprietary app store.

When you launch it and install additional apps, the thousands of TV channels do appear. Meanwhile behind the scenes, with no warnings or permission prompts, the device floods external sites with unauthorized requests, and network traffic spikes sharply.

The researchers uncovered several alarming facts. First, the victim gets enrolled into as many as five botnets at once. The SuperBox runs clients for several proxyware networks simultaneously, which even try to compete with one another by blocking rival software from being installed.

But the real shock was the attacks on the internal network. The TV box’s proxyware places no limits on what its paying clients can actually do on the network. They can reach not only external sites but also devices inside your home network.

Normally, your home router and ISP settings protect you from outside attacks. But proxyware bypasses these barriers because it operates from inside the network. During an experiment, the researchers confirmed that an attacker on the internet can easily leverage the infected set-top box to open the admin panel of a home router, such as a Linksys, which is supposed to be accessible only to its owner when connected to the home Wi-Fi network. This means hackers can try to steal data from other devices in the same household, or even encrypt home network storage (NAS).

At the same time, flaws in SuperBox’s factory firmware let hackers remotely install and run any application with superuser privileges, and the threat is anything but hypothetical. Over three weeks of monitoring, the test set-top box was hit by more than 1300 attacks through the home proxy network. Attackers installed three different types of malware, including a module for launching DDoS attacks.

The malware uses several methods to gain a foothold in the system, and it survives reboots and power failures alike.

How to tell if your set-top box is working for hackers

If you have a cheap TV set-top box or Android TV from a little-known brand, it’s worth checking it for anomalies.

The most reliable method is to review the network traffic. Use the statistics in your router’s control panel, but note that some budget models may lack this feature. This feature is called Traffic Analyzer on Asus routers, Traffic Usage on TP-Link, and Traffic Monitor on Keenetic. Find your TV or set-top box in the device list and check the ratio of downloaded to uploaded data. They should consume a lot of traffic to download video while sending very little. If your box is quietly pushing gigabytes of data out or staying chatty on the network even while idle, that’s a telltale sign it’s infected.

If traffic statistics aren’t available, look for indirect signs:

• The network and memory activity LEDs won’t stop blinking even though no one’s using the device.
• The set-top box’s casing is constantly warm or hot.
• The interface lags behind the remote, and the box freezes at random moments that have nothing to do with heavy video playback.
• Your other devices (computers or phones) are seeing a real drop in internet speed.
• When trying to visit familiar sites over your home Wi-Fi, you’re constantly hit with a CAPTCHA — a sign your network may be compromised and flagged as a spam source.
• Your ISP’s tech support calls you asking about suspicious network loads.

What to do with an infected device

The best solution is to disconnect the device from the internet and dispose of it. If you have to keep using it, follow these steps to minimize the risks:

1. Do a factory (hard) reset. Restore the set-top box to its original state.
2. Take it offline before setting up again. The first time you turn it on after a reset, skip the Wi-Fi setup step and don’t plug in the Ethernet cable.
3. Block app installation. Go to Android settings and disable installation of apps from unknown sources. Be sure to turn off any debugging features if enabled: USB debugging, Wireless debugging, and ADB. Menu item names may differ depending on your Android version and device manufacturer.
4. Isolate it on the network. Set up a guest Wi-Fi network on your router and connect the TV box to it. Enable Client Isolation in your router’s settings, if it has it. This will stop the box from seeing other devices on your home network, which protects your computers and network storage.
5. Check for updates. Once the box is connected to the guest network, check for official firmware updates: manufacturers sometimes patch known vulnerabilities, though with lesser-known brands, you shouldn’t count on it.

Your most reliable safeguards

Buying cheap devices with pirate streaming features and installing software from shady sources is a surefire way to compromise your home network. Your IP address will become a source of malicious activity, which at best gets you blocked by your ISP and at worst puts you on law enforcement’s radar. What’s more, hackers can use the box as a launchpad to attack your home computers and NAS, which can lead to personal data theft or a ransomware attack.

The best protection is to buy devices from trusted brands and pay for legal content. And to rule out someone hijacking control of your network, make sure your router’s admin panel and other home devices are protected with unique, strong passwords. To avoid having to remember them all, use a reliable password manager such as Kaspersky Password Manager. Additionally, the Smart Home Monitor feature included in Kaspersky Premium lets you keep all your devices fully under control.

There may be more things you don’t know about your smart home devices:

• Is your TV box renting out your network?
• Are your TV, smartphone, and smart speakers eavesdropping on you?
• Five rules to stop IP cameras from spying on you
• The hidden risks of cheap Android devices
• Is your router secretly working for foreign intelligence?

Mac users have historically trusted their operating system to keep them safe. That peace of mind mostly comes from Apple’s strict control over its ecosystem, and the fact that macOS has historically faced fewer mass attacks than Windows. However, that doesn’t mean Macs are invulnerable: threats do exist, and new ones emerge all the time. Over just the past few weeks, security researchers have published reports on at least two new campaigns that target Apple devices.

The malware used in one of the campaigns has been dubbed CrashStealer, while the other is known as ClickLock. Both rely on different tricks to force users into entering their Mac password, which attackers then use to steal account credentials, crypto assets, documents, and much more. In today’s post, we take a close look at how CrashStealer operates — and how to avoid falling victim to it.

A videoconferencing app with CrashStealer inside

It was back in May 2026 that researchers spotted the first signs this malware was being developed, and by early July, they caught it operating in the wild. The malware earned its name because of its core mechanism: it disguises itself as the macOS built-in crash reporting tool (CrashReporter) while functioning as an infostealer designed to hijack sensitive data.

Researchers managed to trace one of the websites users visited to download the malware. The site poses as a legitimate platform for distributing the video conferencing tool Werkbit.

According to researchers, this is the site victims used to download Werkbit, which secretly contained the CrashStealer malware loader. Source

However, you can’t just visit the site and download the software. Before downloading, visitors are asked to enter a special meeting PIN. This setup likely allows the attackers to limit the distribution scope by targeting only specific, pre-selected victims. Exactly how the cybercriminals choose their targets and deliver the PIN remains unknown.

The “lucky” users with a code end up installing the initial malicious payload — named Werkbit Setup. Interestingly, it carries a valid Apple developer certificate and has successfully passed Apple’s notarization process — meaning it cleared the automated prescan for malicious code. As a result, the attackers manage to bypass the operating system’s built-in Gatekeeper defense. This allows the payload to launch without triggering the usual untrusted software warnings.

The Werkbit Setup installer is signed with a valid Apple developer certificate and has passed notarization. Source

Once launched, Werkbit Setup first reaches out to GitHub. Researchers believe using this popular platform helps attackers blend in by making these initial network requests look far less suspicious to security tools. After retrieving instructions from a GitHub repository, the program connects directly to the attackers’ server to fetch CrashStealer itself.

The loader then saves the malware to a temporary macOS folder, launches it, and wipes most of the intermediate setup files. As a result, a fully functional infostealer is up and running within seconds of Werkbit Setup starting. By the way, the user never gets any videoconferencing app.

How CrashStealer works

Unlike the Werkbit Setup loader, the CrashStealer malware itself isn’t signed with an Apple developer certificate. To keep users from suspecting anything, the malware disguises itself as the built-in macOS crash reporting tool, CrashReporter, by using the exact same name, app identifier, and a similar icon.

Once launched, CrashStealer completes a sequence of steps to gain access to sensitive data, establish persistence in the system, and cover its tracks:

1. Remove metadata — including the attribute that flags the app as an internet download.
2. Display a fake system prompt asking for the user’s macOS password.
3. Use the previously captured credentials to gain access to Keychain, the built-in macOS password manager.
4. Check the computer for installed security tools and malware analysis software.
5. Collect saved browser passwords, cookies, Keychain contents, and data from other password managers and crypto wallets.
6. Encrypt the data it stole and prepare it for forwarding to the attackers’ server.
7. Create a copy of itself and establish persistence to launch automatically every time macOS boots.
8. Delete temporary files and other installation traces to make detection much harder.

Step two deserves a closer look. The password prompt that the user sees looks extremely convincing. What’s more, the malware immediately verifies whether the credentials are correct: if you make a typo and enter an invalid password, CrashStealer will pop the window right back up to ask you again.

Once launched, CrashStealer displays a pop-up that mimics the standard macOS password request. Source

What data is CrashStealer after?

CrashStealer’s hit list is massive. First and foremost, its operators target Keychain: the built-in macOS password manager where the system stores account credentials, cryptographic keys, certificates, tokens, and more.

Users of third-party password managers aren’t safe either: the malware steals data from 14 of these services, including 1Password, Bitwarden, LastPass, Dashlane, Keeper, KeePassXC, NordPass, Enpass, and RoboForm.

In addition, the malware collects all credentials and cookies stored in Chromium-based browsers — Chrome, Brave, Edge, Opera, Opera GX, Vivaldi, Chromium, and NAVER Whale — as well as Firefox. The attackers clearly have a strong interest in crypto assets: CrashStealer specifically targets data from 80 different crypto wallet extensions, including MetaMask, Phantom, Coinbase Wallet, Trust Wallet, Rabby, Exodus, Keplr, and Solflare.

Finally, the malware scans the Documents and Downloads folders to pick files that might be of interest to the cybercriminals. CrashStealer encrypts all the stolen data with the AES-256-GCM algorithm, ZIP’s it up, and sends it to the attackers’ server.

How to protect your device

The spike in attacks on macOS is a clear wake-up call: Apple users need to get proactive about their security. We recommend:

• Researching apps online before installing them
• Sticking to utilities from official app stores whenever possible
• Using a reliable security solution that blocks malicious websites and stops malware activity on your device
• Keeping all your credentials and banking details in a secure password manager. One option is Kaspersky Password Manager— which, notably, wasn’t listed among the apps targeted by CrashStealer

Kaspersky security solutions detect the malware described in this post and assigns to it the verdicts HEUR:Trojan-Downloader.OSX.Agent.gen and HEUR:Trojan-PSW.OSX.Agent.gen.

A breakup is a major upheaval — the kind that turns life upside down. The familiar order of things, where two people shared the same interests, moments, and often even the same physical space, collapses in an instant, leaving each of you in a world of your own.

Besides that, couples are connected not just in real life, but digitally too. Shared subscriptions, saved addresses and passwords, access to joint cloud storage — all of that used to be woven into your day-to-day life. Moving on emotionally can take a long time, sure, but there are steps you can take right now that will tighten up your security — even if they won’t help you get over your ex.

Here’s what you need to check after a breakup, which services to disconnect, and why you should do it even if the split was amicable.

Digital hygiene: your insurance policy

Cutting off your ex’s access to your online accounts isn’t paranoia — it’s looking out for your own security. A breakup doesn’t automatically sever your digital ties: any access you granted each other during the relationship stays active until someone manually shuts it down. Most of the time, nobody’s plotting to actually exploit it, yet it can still lead to anything from awkward moments to a genuine risk of being tracked.

Take Aleta Dignard-Fung, of Las Vegas, who told NPR that after breaking up with her boyfriend, it didn’t immediately occur to her that he still knew her Spotify password. One day, in the shower with music playing, she noticed her playlist suddenly switch. Her ex had logged in from another device and started playing his own chosen tracks. “It was just kind of like the Spotify wars, and we’d just spend like 10 minutes trying to override each other’s songs,” she admitted. But the fallout isn’t always this lighthearted.

Relationship coach Susan Winter shared a case from her own practice in that same interview. One of her clients simply couldn’t let go of his ex-girlfriend after their breakup. The two had shared an OpenTable account — the restaurant reservation service — and she’d never revoked his access. He started tracking her bookings: where she was going, what time, how many people. That’s how he kept tabs on whether someone new had entered her life.

These two stories, while showing very different behavior from the exes involved, both trace back to the same root cause: accounts that were never properly locked down. In the former case, it led to an awkward moment. In the latter, it led to anxiety and a real sense of being watched. To make sure neither scenario happens to you, it’s worth running through a quick checklist.

Terminate your partner’s sessions

In the settings for your social media, messaging apps, email, and other key services, pull up the list of active sessions and log out everything except your current devices.

Change your passwords

Update the passwords to any key accounts your partner might have known — say, if you used a meaningful date as your password. If you reused the same password across multiple services, change it everywhere. While you’re at it, review your security questions and your backup email or phone number for account recovery — neither should still be tied to your ex. To skip the hassle of memorizing new credentials while still leveling up your security, we recommend using a password manager — it’ll generate a unique, strong password for every account, and save and sync it across all your devices; the only thing you need to remember is a single main password.

Check two-factor authentication and trusted devices

Make sure verification codes only go to your own device. Remove your partner’s devices from your trusted list — you can do this in your Apple and Google account settings.

Split up your shared Apple/Google accounts

If you shared an Apple or Google account, sign out of that. Turn off Family Sharing, iCloud, and backups. Check your shared photo albums too — anything that lands there automatically is visible to your ex as well.

Review your subscriptions

If you shared subscriptions — streaming services, family plans, that kind of thing — cancel them or set up new ones and link your own card.

Check your bank cards

If your ex’s card is linked to a marketplace, delivery app, or rideshare service account you own, remove it from your saved payment methods. If your card is linked to their account and you no longer have access to it, the safest move is to just get your card reissued.

Revoke smart home access

Cut off your ex’s access to cameras, video doorbells, GPS trackers, and smart speakers. If the devices were on a shared account, change the password or move them over to your own personal account.

Review your privacy settings

Check the privacy settings across your accounts on various services and social media using our free online tool, Privacy Checker. It walks you through a privacy configuration tailored to your operating system, platform, and even your browser.

If you notice signs of stalking

Reach out to advocacy or legal aid organizations — they can help you map out the best course of action. It’s also worth leaning on family and close friends who can support you through a tough situation. On Android devices, you can use our security suite with the Who’s Spying on Me feature. It’s designed to help you detect tracking and stalking so you can take the right steps to protect yourself. The feature includes:

• Stalkerware Detection. Flags apps designed to secretly monitor your life and collect data you’d never want shared with anyone else.
• Device Scanner. Finds planted trackers that let someone follow your movements and always know where you are.
• Permissions Control. Shows which apps have access to permissions that could make it easier for someone to spy on you or compromise your privacy.

What can actually help — and what might make things worse — during this difficult time? Check out our other posts:

• Love, AI & robots
• What happens in the bedroom stays in the bedroom
• How chatting with a bot can lead to tragedy
• AI and the new reality of sextortion
• Digital detox: How to take a safe break from screens
• Subscription security: how to protect your account, your wallet… and your sanity

When targeting an organization to steal information, maintaining a low profile is critical for attackers. They typically aim for long-term persistence, which requires avoiding security alerts while preserving access in case they’re detected and the organization initiates incident response or routine password resets. Malware such as infostealers or ostensibly legitimate remote monitoring and management (RMM) tools fail the first requirement: their use triggers EDR and generates suspicious events in SIEM consoles. Relying on stolen credentials conflicts with the second requirement: the moment the security team suspects a compromise, passwords can be changed immediately — terminating access. If attackers attempt to steal browser cookies instead of passwords, they face a different challenge: many online services now correlate device characteristics with the expected session cookie and block access if the cookie is used on an unrecognized device. Furthermore, cookie theft protection mechanisms implemented in Chromium-based browsers (such as Chrome, Edge, and Opera) this year have made this approach significantly more difficult.

To address this persistence challenge, the ToddyCat APT — whose main game is spying — developed a novel technique. Kaspersky experts discovered this method during an incident investigation and named it Shadow Token via Remote Debug (STRD). This technique allows the attackers to establish reliable, persistent access to a victim’s mailbox and other resources in Google Workspace. With minor adjustments, the same approach could potentially be adapted to target other services that grant third-party application access via OAuth 2.0 authentication.

How an STRD attack works

First, the attackers must compromise the victim’s system with malware. In past campaigns, ToddyCat gained initial access to organizations by exploiting known vulnerabilities in server software and distributing malicious loaders via messaging apps. The specific employee targeted by the attackers might not notice the intrusion at all. This can occur, for example, if the adversary first obtains privileged administrative credentials and uses them to deploy the malware onto targeted machines remotely. Crucially, the deployment and execution of this malware mustn’t trigger immediate security alerts.

Once active, the malware executes an STRD attack, connecting the attackers’ remote service to the victim’s mailbox using the OAuth 2.0 protocol. This process requires no user interaction and shows no visible activity on the screen. To the cloud environment (Google Workspace, in the case at hand), the activity appears as if the user has legitimately authorized a third-party app for email access or data backup.

After that, the malware can terminate its operations and even delete itself from the system. The adversary retains direct access to the mailbox using the acquired OAuth token — and they need no connection to the victim’s endpoint or to the corporate network for that. Depending on the organization’s Google Workspace configuration, this access can persist for an extended period and survive subsequent password resets.

The core concept of Shadow Token via Remote Debug

At the heart of this attack is a connection to Google Workspace services via OAuth 2.0. This is a legitimate workflow used whenever a third-party application requests access to calendar data, emails, or Google Drive files. For example, to display calendar meetings in Zoom and automatically generate conference links, a user must authorize Zoom to access Google services. Similarly, configuring a third-party email client or calendar app requires granting permission. During this authorization process, the service requesting access opens a new browser window. In this window, Google Workspace first prompts the user to select the appropriate account. Once the account is chosen, the subsequent screen displays the specific permissions requested by the third-party app, allowing the user to either approve or deny access. For this scenario to proceed seamlessly, the user must already be authenticated to Google services in their browser — which is typically the case in organizations using Google Workspace. If the user isn’t authenticated, additional steps for entering credentials and completing multi-factor authentication are introduced into the sequence.

The ToddyCat hackers developed a malicious tool called Umbrij to facilitate a two-step covert authorization process when the user is already authenticated in Google. First, the malware identifies the browsers installed on the system, and locates the specific folder storing the user’s active profile for each. The attackers target Chrome and Edge, as these are the browsers most likely serving as the primary ones within the organization.

Next, Umbrij copies the entire user profile folder to a different directory on the machine. It then launches an instance of the browser, specifying the path to the duplicated profile via the command line. Because this duplicate profile contains the user’s session cookies, websites with saved credentials won’t prompt for re-authentication. Furthermore, since this occurs on the exact same computer where the primary browser is running, online services detect no anomalies. The browsing history for this newly launched instance is isolated within the new folder, keeping it hidden from the user’s main account activity.

Crucially, the browser is launched in a dedicated debugging mode typically reserved for web development. The browser window and user interface don’t appear on the screen at all (headless mode). Instead, the browser can be controlled through a debugging port using the DevTools protocol, allowing the malware to issue commands and read the state of the screen. To orchestrate these actions, Umbrij leverages Puppeteer, a legitimate automation library.

After verifying that the debugging browser instance has launched successfully, Umbrij opens a legitimate Google Workspace OAuth screen within it. The request sent to Google is engineered to bypass additional security checks while requesting maximum access privileges. For the application ID — the identity supposedly requesting these extensive permissions — the malware impersonates one of two legitimate tools: Google Workspace Migration for Microsoft Outlook (GWMMO), or Google Workspace Sync for Microsoft Outlook (GWSMO).

When Google opens the window within the headless browser, Umbrij uses debugging tools to programmatically click on the corporate account name and the confirmation buttons. As a result, Google generates an authorization code for the app. Umbrij extracts and saves this code, subsequently forwarding it to the attackers’ command-and-control server. Finally, operating entirely within their own infrastructure rather than on the victim’s computer, the attackers exchange this authorization code for an OAuth access token. This single token is all they need to maintain long-term unrestricted access to the mailbox.

How to protect against OAuth token theft

If a Google Workspace account is compromised, incident response measures must include the following steps after collecting the necessary logs and other forensic data for investigation:

• Resetting the affected user’s password
• Terminating all active web sessions for the user
• Revoking OAuth tokens and third-party app permissions
• Reviewing and removing access granted through legacy App Passwords

In addition, security and IT teams must systematically audit issued OAuth permissions, revoke unjustifiable access rights, and restrict capabilities that allow excessive or unauthorized permission grants. We covered this topic in detail in our article on blocking unwanted AI assistants.

How to prevent exploitation of Shadow Token via Remote Debug

While Kaspersky users are protected against the Umbrij tool, security teams should proactively implement policies that prevent standard users from launching browsers in debugging mode. This functionality is intended exclusively for website and web app developers. This restriction can be enforced through the DeveloperToolsAvailability group policy (available for both Chrome and Edge).

Additionally, configure monitoring within your SIEM/XDR to track the launch of browser instances with an active debugging port. This event serves as a strong indicator of this specific attack technique.

Microsoft said it will change Edge’s password handling as a “defense‑in‑depth” measure.

Originally, Edge decrypted the entire saved‑password store on startup and kept all credentials resident in process memory in clear text for the whole browser session, regardless of whether a given credential was ever used or not.

A short while ago, Microsoft said this plaintext password behavior was by design. Now, Microsoft has changed course, and the new password-handling behavior is already present in Canary (the experimental preview version of Microsoft Edge), with rollout prioritized across all channels.

The researcher who originally flagged the issue said:

“Edge is the only Chromium‑based browser I’ve tested that behaves this way. By contrast, Chrome uses a design that makes it far harder for attackers to extract saved passwords by simply reading process memory.”

Microsoft Edge Security Lead Gareth Evans said Microsoft is now taking a broader view and has committed to changing Edge so that saved passwords are no longer loaded into memory on startup as clear text. As a result, exposure will be reduced as a defense‑in‑depth improvement. That means even if an attacker has administrative control of a device, it becomes harder to harvest all the passwords.

According to Microsoft:

“Going forward, Microsoft Edge will no longer load all saved passwords into memory at browser startup. Instead, passwords will be decrypted only when needed for autofill or password management operations.”

The change is already live in the Edge Canary channel and will be included in the next update for all supported Edge releases (build 148 and newer across Stable, Beta, Dev, Canary, and Extended Stable).

The reason for this change is probably more reputational and strategic rather than an acknowledgment of an exploitable vulnerability. Microsoft seems to want to align reality with its “secure by design” messaging and reduce a very visible, easy‑to‑demo weakness, even if it still doesn’t treat it as a classic memory‑disclosure bug.

Passwords in your browser

Please note that this change just means Edge will become roughly as secure an option to store passwords as every other Chromium-based browser.

Your browser password manager gives you ease of use, but that comes with some security tradeoffs. Of course, password managers aren’t foolproof either, so it’s important to decide for yourself where you store your passwords.

If you’re confident a website is safe, and anyone who can access it under your account wouldn’t learn anything sensitive, feel free to store the password in your browser, but disable autofill so you stay in control.

Use MFA where possible. It enormously reduces the risk if someone gets hold of your password. And avoid using the browser password manager to store your credit card details or other sensitive personally identifiable information, such as medical information.

Let’s face it, an incognito window can only do so much. 
 
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Some time ago, we discussed whether you should allow your browser to remember your passwords.

In that article we mentioned the importance of encryption.

“With a browser password manager, someone with access to your browser could see your passwords in clear text, although Windows can be set to ask for authentication (the same you use at startup of your device).”

The typical behavior of browser password managers is to store passwords encrypted on disk, tied to your user account, and protected by the operating system.

But recently, a security researcher systematically tested every major Chromium-based browser for how they handle credentials in memory. The researcher found that Edge was the only one loading the entire password vault into plaintext process memory at startup, where it remains for the duration of the session.  

Chrome and other Chromium browsers were observed to only decrypt a password when needed (autofill or “show password”), not the whole vault, and to use mechanisms like app‑bound encryption for keys. Edge does not use those protections in this context.

So, the researcher decided to write a proof-of-concept (PoC) demonstrating that accessing that vault doesn’t rely on zero-days or complex exploitation. It relies on the relatively simple ability to read process memory, which does require elevated privileges.

But when the researcher reported the issue to Microsoft, the response was underwhelming. The company’s official response was that the behavior is “by design.” The reasoning most likely is that this behavior speeds up sign‑in and autofill, and attackers would already need a compromised machine or elevated access to read RAM, which Microsoft treats as out of scope for this design decision.

Which is basically true. An attacker already needs significant foothold: for example, code execution on the box and the ability to read Edge’s process memory, often requiring elevated privileges. This is not a remote, unauthenticated bug in the browser, but the design makes post‑compromise credential harvesting easier. And it’s a capability many infostealers already have.

It’s just another thing an attacker can do once they’ve compromised your machine. Combined with this academic study from 2024, which found many password managers leak plaintext passwords into memory under some conditions, it leads us to repeat our advice.

Should you allow your browser to remember your passwords?

Your browser password manager gives you ease of use, but that costs you some security. Of course, password managers aren’t foolproof either, so it’s important to decide for yourself where you store your passwords.

If you’re confident the website is safe, and anyone that can access it under your account won’t learn anything new, feel free to store the password in your browser, but disable autofill so you stay in control.

Use MFA where possible. It enormously reduces the risk should someone get hold of your password. And refrain from using the browser password manager to store your credit card details or other sensitive personally identifiable information, such as medical information.

But we’d add that, among the major browsers, Edge appears to be the weakest option if you still choose to use a built‑in password manager.

Stop threats before they can do any harm.

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Palo Alto’s crosswalk signals were hacked last year. Turns out the city never changed the default passwords.

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