The year 2025 saw a record-breaking number of attacks on Android devices. Scammers are currently riding a few major waves: the hype surrounding AI apps, the urge to bypass site blocks or age checks, the hunt for a bargain on a new smartphone, the ubiquity of mobile banking, and, of course, the popularity of NFC. Let’s break down the primary threats of 2025–2026, and figure out how to keep your Android device safe in this new landscape.

Sideloading

Malicious installation packages (APK files) have always been the Final Boss among Android threats, despite Google’s multi-year efforts to fortify the OS. By using sideloading — installing an app via an APK file instead of grabbing it from the official store — users can install pretty much anything, including straight-up malware. And neither the rollout of Google Play Protect, nor the various permission restrictions for shady apps have managed to put a dent in the scale of the problem.

According to preliminary data from Kaspersky for 2025, the number of detected Android threats grew almost by half. In the third quarter alone, detections jumped by 38% compared to the second. In certain niches, like Trojan bankers, the growth was even more aggressive. In Russia alone, the notorious Mamont banker attacked 36 times more users than it did the previous year, while globally this entire category saw a nearly fourfold increase.

Today, bad actors primarily distribute malware via messaging apps by sliding malicious files into DMs and group chats. The installation file usually sports an enticing name (think “party_pics.jpg.apk” or “clearance_sale_catalog.apk”), accompanied by a message “helpfully” explaining how to install the package while bypassing the OS restrictions and security warnings.

Once a new device is infected, the malware often spams itself to everyone in the victim’s contact list.

Search engine spam and email campaigns are also trending, luring users to sites that look exactly like an official app store. There, they’re prompted to download the “latest helpful app”, such as an AI assistant. In reality, instead of an installation from an official app store, the user ends up downloading an APK package. A prime example of these tactics is the ClayRat Android Trojan, which uses a mix of all these techniques to target Russian users. It spreads through groups and fake websites, blasts itself to the victim’s contacts via SMS, and then proceeds to steal the victim’s chat logs and call history; it even goes as far as snapping photos of the owner using the front-facing camera. In just three months, over 600 distinct ClayRat builds have surfaced.

The scale of the disaster is so massive that Google even announced an upcoming ban on distributing apps from unknown developers starting in 2026. However, after a couple of months of pushback from the dev community, the company pivoted to a softer approach: unsigned apps will likely only be installable via some kind of superuser mode. As a result, we can expect scammers to simply update their how-to guides with instructions on how to toggle that mode on.

Kaspersky for Android will help you protect yourself from counterfeit and trojanized APK files. Unfortunately, due to Google’s decision, our Android security apps are currently unavailable on Google Play. We’ve previously provided detailed information on how to install our Android apps with a 100% guarantee of authenticity.

NFC relay attacks

Once an Android device is compromised, hackers can skip the middleman to steal the victim’s money directly thanks to the massive popularity of mobile payments. In the third quarter of 2025 alone, over 44 000 of these attacks were detected in Russia alone — a 50% jump from the previous quarter.

There are two main scams currently in play: direct and reverse NFC exploits.

Direct NFC relay is when a scammer contacts the victim via a messaging app and convinces them to download an app — supposedly to “verify their identity” with their bank. If the victim bites and installs it, they’re asked to tap their physical bank card against the back of their phone and enter their PIN. And just like that the card data is handed over to the criminals, who can then drain the account or go on a shopping spree.

Reverse NFC relay is a more elaborate scheme. The scammer sends a malicious APK and convinces the victim to set this new app as their primary contactless payment method. The app generates an NFC signal that ATMs recognize as the scammer’s card. The victim is then talked into going to an ATM with their infected phone to deposit cash into a “secure account”. In reality, those funds go straight into the scammer’s pocket.

We break both of these methods down in detail in our post, NFC skimming attacks.

NFC is also being leveraged to cash out cards after their details have been siphoned off through phishing websites. In this scenario, attackers attempt to link the stolen card to a mobile wallet on their own smartphone — a scheme we covered extensively in NFC carders hide behind Apple Pay and Google Wallet.

The stir over VPNs

In many parts of the world, getting onto certain websites isn’t as simple as it used to be. Some sites are blocked by local internet regulators or ISPs via court orders; others require users to pass an age verification check by showing ID and personal info. In some cases, sites block users from specific countries entirely just to avoid the headache of complying with local laws. Users are constantly trying to bypass these restrictions —and they often end up paying for it with their data or cash.

Many popular tools for bypassing blocks — especially free ones — effectively spy on their users. A recent audit revealed that over 20 popular services with a combined total of more than 700 million downloads actively track user location. They also tend to use sketchy encryption at best, which essentially leaves all user data out in the open for third parties to intercept.

Moreover, according to Google data from November 2025, there was a sharp spike in cases where malicious apps are being disguised as legitimate VPN services to trick unsuspecting users.

The permissions that this category of apps actually requires are a perfect match for intercepting data and manipulating website traffic. It’s also much easier for scammers to convince a victim to grant administrative privileges to an app responsible for internet access than it is for, say, a game or a music player. We should expect this scheme to only grow in popularity.

Trojan in a box

Even cautious users can fall victim to an infection if they succumb to the urge to save some cash. Throughout 2025, cases were reported worldwide where devices were already carrying a Trojan the moment they were unboxed. Typically, these were either smartphones from obscure manufacturers or knock-offs of famous brands purchased on online marketplaces. But the threat wasn’t limited to just phones; TV boxes, tablets, smart TVs, and even digital photo frames were all found to be at risk.

It’s still not entirely clear whether the infection happens right on the factory floor or somewhere along the supply chain between the factory and the buyer’s doorstep, but the device is already infected before the first time it’s turned on. Usually, it’s a sophisticated piece of malware called Triada, first identified by Kaspersky analysts back in 2016. It’s capable of injecting itself into every running app to intercept information: stealing access tokens and passwords for popular messaging apps and social media, hijacking SMS messages (confirmation codes: ouch!), redirecting users to ad-heavy sites, and even running a proxy directly on the phone so attackers can browse the web using the victim’s identity.

Technically, the Trojan is embedded right into the smartphone’s firmware, and the only way to kill it is to reflash the device with a clean OS. Usually, once you dig into the system, you’ll find that the device has far less RAM or storage than advertised — meaning the firmware is literally lying to the owner to sell a cheap hardware config as something more premium.

Another common pre-installed menace is the BADBOX 2.0 botnet, which also pulls double duty as a proxy and an ad-fraud engine. This one specializes in TV boxes and similar hardware.

How to go on using Android without losing your mind

Despite the growing list of threats, you can still use your Android smartphone safely! You just have to stick to some strict mobile hygiene rules.

• Install a comprehensive security solution on all your smartphones. We recommend Kaspersky for Android to protect against malware and phishing.
• Avoid sideloading apps via APKs whenever you can use an app store instead. A known app store — even a smaller one — is always a better bet than a random APK from some random website. If you have no other choice, download APK files only from official company websites, and double-check the URL of the page you’re on. If you aren’t 100% sure what the official site is, don’t just rely on a search engine; check official business directories or at least Wikipedia to verify the correct address.
• Read OS warnings carefully during installation. Don’t grant permissions if the requested rights or actions seem illogical or excessive for the app you’re installing.
• Under no circumstances should you install apps from links or attachments in chats, emails, or similar communication channels.
• Never tap your physical bank card against your phone. There is absolutely no legitimate scenario where doing this would be for your own benefit.
• Do not enter your card’s PIN into any app on your phone. A PIN should only ever be requested by an ATM or a physical payment terminal.
• When choosing a VPN, stick to paid ones from reputable companies.
• Buy smartphones and other electronics from official retailers, and steer clear of brands you’ve never heard of. Remember: if a deal seems too good to be true, it almost certainly is.

Other major Android threats from 2025:

• Pixnapping vulnerability: unblockable screenshots of your Android phone
• Spyware that pretends to be an antivirus
• Data theft during smartphone charging
• SparkCat trojan stealer infiltrates App Store and Google Play, steals data from photos

Thanks to the convenience of NFC and smartphone payments, many people no longer carry wallets or remember their bank card PINs. All their cards reside in a payment app, and using that is quicker than fumbling for a physical card. Mobile payments are also secure — the technology was developed relatively recently and includes numerous anti-fraud protections. Still, criminals have invented several ways to abuse NFC and steal your money. Fortunately, protecting your funds is straightforward: just know about these tricks and avoid risky NFC usage scenarios.

What are NFC relay and NFCGate?

NFC relay is a technique where data wirelessly transmitted between a source (like a bank card) and a receiver (like a payment terminal) is intercepted by one intermediate device, and relayed in real time to another. Imagine you have two smartphones connected via the internet, each with a relay app installed. If you tap a physical bank card against the first smartphone and hold the second smartphone near a terminal or ATM, the relay app on the first smartphone will read the card’s signal using NFC, and relay it in real time to the second smartphone, which will then transmit this signal to the terminal. From the terminal’s perspective, it all looks like a real card is tapped on it — even though the card itself might physically be in another city or country.

This technology wasn’t originally created for crime. The NFCGate app appeared in 2015 as a research tool after it was developed by students at the Technical University of Darmstadt in Germany. It was intended for analyzing and debugging NFC traffic, as well as for education purposes and experiments with contactless technology. NFCGate was distributed as an open-source solution and used in academic and enthusiast circles.

Five years later, cybercriminals caught on to the potential of NFC relay and began modifying NFCGate by adding mods that allowed it to run through a malicious server, disguise itself as legitimate software, and perform social engineering scenarios.

What began as a research project morphed into the foundation for an entire class of attacks aimed at draining bank accounts without physical access to bank cards.

A history of misuse

The first documented attacks using a modified NFCGate occurred in late 2023 in the Czech Republic. By early 2025, the problem had become large scale  and noticeable: cybersecurity analysts uncovered more than 80 unique malware samples built on the NFCGate framework. The attacks evolved rapidly, with NFC relay capabilities being integrated into other malware components.

By February 2025, malware bundles combining CraxsRAT and NFCGate emerged, allowing attackers to install and configure the relay with minimal victim interaction. A new scheme, a so-called “reverse” version of NFCGate, appeared in spring 2025, fundamentally changing the attack’s execution.

Particularly noteworthy is the RatOn Trojan, first detected in the Czech Republic. It combines remote smartphone control with NFC relay capabilities, letting attackers target victims’ banking apps and cards through various technique combinations. Features like screen capture, clipboard data manipulation, SMS sending, and stealing info from crypto wallets and banking apps give criminals an extensive arsenal.

Cybercriminals have also packaged NFC relay technology into malware-as-a-service (MaaS) offerings, and reselling them to other threat actors through subscription. In early 2025, analysts uncovered a new and sophisticated Android malware campaign in Italy, dubbed SuperCard X. Attempts to deploy SuperCard X were recorded in Russia in May 2025, and in Brazil in August of the same year.

The direct NFCGate attack

The direct attack is the original criminal scheme exploiting NFCGate. In this scenario, the victim’s smartphone plays the role of the reader, while the attacker’s phone acts as the card emulator.

First, the fraudsters trick the user into installing a malicious app disguised as a banking service, a system update, an “account security” app, or even a popular app like TikTok. Once installed, the app gains access to both NFC and the internet — often without requesting dangerous permissions or root access. Some versions also ask for access to Android accessibility features.

Then, under the guise of identity verification, the victim is prompted to tap their bank card to their phone. When they do, the malware reads the card data via NFC and immediately sends it to the criminals’ server. From there, the information is relayed to a second smartphone held by a money mule, who helps extract the money. This phone then emulates the victim’s card to make payments at a terminal or withdraw cash from an ATM.

The fake app on the victim’s smartphone also asks for the card PIN — just like at a payment terminal or ATM — and sends it to the attackers.

In early versions of the attack, criminals would simply stand ready at an ATM with a phone to use the duped user’s card in real time. Later, the malware was refined so the stolen data could be used for in-store purchases in a delayed, offline mode, rather than in a live relay.

For the victim, the theft is hard to notice: the card never left their possession, they didn’t have to manually enter or recite its details, and the bank alerts about the withdrawals can be delayed or even intercepted by the malicious app itself.

Among the red flags that should make you suspect a direct NFC attack are:

• prompts to install apps not from official stores;
• requests to tap your bank card on your phone.

The reverse NFCGate attack

The reverse attack is a newer, more sophisticated scheme. The victim’s smartphone no longer reads their card — it emulates the attacker’s card. To the victim, everything appears completely safe: there’s no need to recite card details, share codes, or tap a card to the phone.

Just like with the direct scheme, it all starts with social engineering. The user gets a call or message convincing them to install an app for “contactless payments”, “card security”, or even “using central bank digital currency”. Once installed, the new app asks to be set as the default contactless payment method — and this step is critically important. Thanks to this, the malware requires no root access — just user consent.

The malicious app then silently connects to the attackers’ server in the background, and the NFC data from a card belonging to one of the criminals is transmitted to the victim’s device. This step is completely invisible to the victim.

Next, the victim is directed to an ATM. Under the pretext of “transferring money to a secure account” or “sending money to themselves”, they are instructed to tap their phone on the ATM’s NFC reader. At this moment, the ATM is actually interacting with the attacker’s card. The PIN is dictated to the victim beforehand — presented as “new” or “temporary”.

The result is that all the money deposited or transferred by the victim ends up in the criminals’ account.

The hallmarks of this attack are:

• requests to change your default NFC payment method;
• a “new” PIN;
• any scenario where you’re told to go to an ATM and perform actions there under someone else’s instructions.

How to protect yourself from NFC relay attacks

NFC relay attacks rely not so much on technical vulnerabilities as on user trust. Defending against them comes down to some simple precautions.

• Make sure you keep your trusted contactless payment method (like Google Pay or Samsung Pay) as the default.
• Never tap your bank card on your phone at someone else’s request, or because an app tells you to. Legitimate apps might use your camera to scan a card number, but they’ll never ask you to use the NFC reader for your own card.
• Never follow instructions from strangers at an ATM — no matter who they claim to be.
• Avoid installing apps from unofficial sources. This includes links sent via messaging apps, social media, SMS, or recommended during a phone call — even if they come from someone claiming to be customer support or the police.
• Use comprehensive security on your Android smartphones to block scam calls, prevent visits to phishing sites, and stop malware installation.
• Stick to official app stores only. When downloading from a store, check the app’s reviews, number of downloads, publication date, and rating.
• When using an ATM, rely on your physical card instead of your smartphone for the transaction.
• Make it a habit to regularly check the “Payment default” setting in your phone’s NFC menu. If you see any suspicious apps listed, remove them immediately and run a full security scan on your device.
• Review the list of apps with accessibility permissions — this is a feature commonly abused by malware. Either revoke these permissions for any suspicious apps, or uninstall the apps completely.
• Save the official customer service numbers for your banks in your phone’s contacts. At the slightest hint of foul play, call your bank’s hotline directly without delay.
• If you suspect your card details may have been compromised, block the card immediately.

Admit it: you’ve been meaning to jump on the latest NFT reincarnation — Telegram Gifts — but just haven’t gotten around to it. It’s the hottest trend right now. Developers are churning out collectible images in partnership with celebs like Snoop Dogg. All your friends’ profiles are already decked out with these modish pictures, and you’re dying to hop on this hype train — but pay as little as possible for it.

And then it happens — a stranger messages you privately with a generous offer: a chance to snag a couple of these digital gifts — with no investment required. A bot that looks completely legit is running an airdrop. In the world of NFTs, an airdrop is a promotional stunt where a small number of new crypto assets are given away for free. The buzzword has been adopted on Telegram, thanks to the crypto nature of these gifts and the NFT mechanics running under the hood.

They’re offering you these gift images for free — or so they say. You could later attach them to your profile or sell them for Telegram’s native currency, Toncoin. You don’t even have to tap an external link. Just hit a button in the message, launch a Mini App right inside Telegram itself, and enter your login credentials. And then… your account immediately gets hijacked. You won’t get any gifts, and overall, you’ll be left with anything but a celebratory feeling.

Today, we break down a phishing scheme that exploits Telegram’s built-in Mini Apps, and share tips to help you avoid falling for these attacks.

How the new phishing scheme works

The principle of classic phishing is straightforward: the user gets a link to a fake website that mimics a legitimate sign-in form. When the victim enters their credentials, this data goes straight to the scammer. However, phishing tactics are constantly evolving, and this new attack method is far more insidious.

The bad actors create phishing Mini Apps directly inside Telegram. These appear as standard web pages but are embedded within the messaging app’s interface instead of opening in an external browser. To the user, these apps look completely legitimate. After all, they run within the official Telegram app itself.

This leads the victim to think, “If this app runs inside Telegram, there must be some kind of vetting process for these apps. Surely they wouldn’t let an obvious scam through?” In practice, it turns out that’s not the case at all.

How is this scheme even a thing?

A core security issue with Telegram Mini Apps is that the platform does almost no vetting before an app goes live. This is a world apart from the strict review processes used by Google Play and the App Store — although even there, obvious malware occasionally slips through.

On Telegram, it’s far easier for bad actors. Essentially, anyone who wishes to create and launch a Mini App can do so. Telegram does not review the code, functionality, or the developer’s intent. This turns a security flaw within a messaging service boasting nearly a billion global users into a global-scale problem. To make matters worse, moderation of these Mini Apps within Telegram is entirely reactive — meaning action is only taken after users start complaining or law enforcement gets involved.

In this case, the bait was “gifts” from UFC fighters: a giveaway of “papakhas” — digital gift images of the traditional Dagestani hat released by Telegram in partnership with Khabib Nurmagomedov. An auction for these items did take place, with Pavel Durov even posting about it on his X and Telegram (Khabib reposted these announcements but later deleted them after the auction ended). However, there were only 29 000 of these “papakhas” released, which wasn’t enough to satisfy all the eager fans. Scammers seized on the opportunity, assuring fans they could get the exclusive items for free. The phishing campaign was a targeted one — focusing on users who’d been active on the athlete’s channel.

How the scammers lull their victims

The criminals leveraged the name of the popular Portals platform — a legitimate service for games, apps, and entertainment within Telegram. They created a series of Mini Apps that were visually almost indistinguishable from the real ones, and promoted them as free giveaways — airdrops.

That said, the scam campaigns themselves show signs of being rushed and cutting design and copywriting costs — with obvious signs of AI involvement. Some of the messages contain leftover text fragments clearly generated by a neural network, which the scammers either forgot or couldn’t be bothered to edit.

How to protect your Telegram account from being hacked

The golden security rules are simple: stay vigilant, and learn the key hallmarks of these attacks:

• Verify the source. If you receive a link promising a giveaway from a celebrity or even Telegram itself but sent from an unfamiliar account or a dubious group, don’t click. Cross-check through the celebrity or company’s official channel to see if they’re actually running a promo like that.
• Inspect the account verification badge. Ascertain that the blue checkmark is real and not just an emoji status or part of the profile name. You can verify this by simply tapping that checkmark icon in the profile. If it’s a Premium emoji status, Telegram will explicitly tell you so. If a checkmark emoji is simply added to the profile name, tapping it doesn’t do anything. But if the account is genuinely verified, tapping the blue checkmark will bring up an official confirmation message from Telegram.
• Don’t be in a rush to authenticate in Mini Apps. Legitimate Telegram apps typically don’t require you to sign in again through a form inside the Mini App. If you’re prompted to enter your phone number or a verification code, it’s likely a phishing attempt.
• Look for signs of AI-generated text or design. Weird grammar, unnatural phrasing, or leftover neural network prompts within a message are a red flag. Scammers frequently use AI-powered generation to churn out text quickly and cheaply.
• Turn on two-step verification (your Telegram password). Do this right now in Settings → Privacy and Security → Two-Step Verification. Even if a scammer manages to get your phone number and SMS code, they won’t be able to access your account without this password. Obviously, never share your password with anyone — it’s meant only for you to sign in to your Telegram account.
• Use a passkey to secure your account. A recent Telegram update added the ability to securely sign in with a passkey. We’ve covered using passkeys with popular services and the associated caveats in detail. A passkey makes it nearly impossible for a malicious actor to steal your account. You can set one up in Settings → Privacy and Security → Passkeys.
• Store your password and passkey in a password manager. If you’ve secured your account with both a password and a passkey, remember that a weak, reused, or compromised password can still be the proverbial “spare key under the mat” for attackers — even if the “front door” is locked with a passkey. Therefore, we recommend creating a strong, unique password for Telegram and storing it — along with your passkey — in Kaspersky Password Manager. This keeps your credentials and keys available across all your devices.
• Install Kaspersky for Android on your smartphone. Its new anti-phishing technology protects you from phishing links embedded in notifications from any app.

What to do if your Telegram account was already stolen

The key is keeping calm and acting swiftly. You have just 24 hours to reclaim your account, or you risk losing it permanently. Follow the step-by-step guide to restoring access in our post What to do if your Telegram account is hacked.

Finally, a reminder that has become our classic mantra: if an offer looks too good to be true, it almost certainly is. Always verify information through official channels, and never enter your passwords or passkeys into unofficial apps or forms — even if they look legit. Stay vigilant and stay safe.

Want more tips on securing your messenger accounts and chats? Check out our related posts:

• Messengers 101: safety and privacy advice
• Messaging other platforms via WhatsApp: the pros and cons
• WhatsApp and Telegram account hijacking: How to protect yourself against scams
• What to do if your WhatsApp account gets hacked
• What to do if your Telegram account is hacked

Attackers often go after outdated and unused test accounts, or stumble upon publicly accessible cloud storage containing critical data that’s a bit dusty. Sometimes an attack exploits a vulnerability in an app component that was actually patched, say, two years ago. As you read these breach reports, a common theme emerges: the attacks leveraged something outdated: a service, a server, a user account… Pieces of corporate IT infrastructure that sometimes fall off the radar of IT and security teams. They become, in essence, unmanaged, useless, and simply forgotten. These IT zombies create risks for information security, regulatory compliance, and lead to unnecessary operational costs. This is generally an element of shadow IT — with one key difference: nobody wants, knows about, or benefits from these assets.

In this post, we try to identify which assets demand immediate attention, how to identify them, and what a response should look like.

Physical and virtual servers

Priority: high. Vulnerable servers are entry points for cyberattacks, and they continue consuming resources while creating regulatory compliance risks.

Prevalence: high. Physical and virtual servers are commonly orphaned in large infrastructures following migration projects, or after mergers and acquisitions. Test servers no longer used after IT projects go live, as well as web servers for outdated projects running without a domain, are also frequently forgotten. The scale of the problem is illustrated by Lets Encrypt statistics: in 2024, half of domain renewal requests came from devices no longer associated with the requested domain. And there are roughly a million of these devices in the world.

Detection: the IT department needs to implement an Automated Discovery and Reconciliation (AD&R) process that combines the results of network scanning and cloud inventory with data from the Configuration Management Database (CMDB). It enables the timely identification of outdated or conflicting information about IT assets, and helps locate the forgotten assets themselves.

This data should be supplemented by external vulnerability scans that cover all of the organization’s public IPs.

Response: establish a formal, documented process for decommissioning/retiring servers. This process needs to include verification of complete data migration, and verified subsequent destruction of data on the server. Following these steps, the server can be powered down, recycled, or repurposed. Until all procedures are complete, the server needs to be moved to a quarantined, isolated subnet.

To mitigate this issue for test environments, implement an automated process for their creation and decommission. A test environment should be created at the start of a project, and dismantled after a set period or following a certain duration of inactivity. Strengthen the security of test environments by enforcing their strict isolation from the primary (production) environment, and by prohibiting the use of real, non-anonymized business data in testing.

Forgotten user, service, and device accounts

Priority: critical. Inactive and privileged accounts are prime targets for attackers seeking to establish network persistence or expand their access within the infrastructure.

Prevalence: very high. Technical service accounts, contractor accounts, and non-personalized accounts are among the most commonly forgotten.

Detection: conduct regular analysis of the user directory (Active Directory in most organizations) to identify all types of accounts that have seen no activity over a defined period (a month, quarter, or year). Concurrently, it’s advisable to review the permissions assigned to each account, and remove any that are excessive or unnecessary.

Response: after checking with the relevant service owner on the business side or employee supervisor, outdated accounts should be simply deactivated or deleted. A comprehensive Identity and Access Management system (IAM) offers a scalable solution to this problem. In this system, the creation, deletion, and permission assignment for accounts are tightly integrated with HR processes.

For service accounts, it’s also essential to routinely review both the strength of passwords, and the expiration dates for access tokens — rotating them as necessary.

Forgotten data stores

Priority: critical. Poorly controlled data in externally accessible databases, cloud storage and recycle bins, and corporate file-sharing services — even “secure” ones — has been a key source of major breaches in 2024–2025. The data exposed in these leaks often includes document scans, medical records, and personal information. Consequently, these security incidents also lead to penalties for non-compliance with regulations such as HIPAA, GDPR, and other data-protection frameworks governing the handling of personal and confidential data.

Prevalence: high. Archive data, data copies held by contractors, legacy database versions from previous system migrations — all of these often remain unaccounted for and accessible for years (even decades) in many organizations.

Detection: given the vast variety of data types and storage methods, a combination of tools is essential for discovery:

• Native audit subsystems within major vendor platforms, such as AWS Macie, and Microsoft Purview
• Specialized Data Discovery and Data Security Posture Management solutions
• Automated analysis of inventory logs, such as S3 Inventory

Unfortunately, these tools are of limited use if a contractor creates a data store within its own infrastructure. Controlling that situation requires contractual stipulations granting the organization’s security team access to the relevant contractor storage, supplemented by threat intelligence services capable of detecting any publicly exposed or stolen datasets associated with the company’s brand.

Response: analyze access logs and integrate the discovered storage into your DLP and CASB tools to monitor its usage — or to confirm it’s truly abandoned. Use available tools to securely isolate access to the storage. If necessary, create a secure backup, then delete the data. At the organizational policy level, it’s crucial to establish retention periods for different data types, mandating their automatic archiving and deletion upon expiry. Policies must also define procedures for registering new storage systems, and explicitly prohibit the existence of ownerless data that’s accessible without restrictions, passwords, or encryption.

Unused applications and services on servers

Priority: medium. Vulnerabilities in these services increase the risk of successful cyberattacks, complicate patching efforts, and waste resources.

Prevalence: very high. services are often enabled by default during server installation, remain after testing and configuration work, and continue to run long after the business process they supported has become obsolete.

Detection: through regular audits of software configurations. For effective auditing, servers should adhere to a role-based access model, with each server role having a corresponding list of required software. In addition to the CMDB, a broad spectrum of tools helps with this audit: tools like OpenSCAP and Lynis — focused on policy compliance and system hardening; multi-purpose tools like OSQuery; vulnerability scanners such as OpenVAS; and network traffic analyzers.

Response: conduct a scheduled review of server functions with their business owners. Any unnecessary applications or services found running should be disabled. To minimize such occurrences, implement the principle of least privilege organization-wide and deploy hardened base images or server templates for standard server builds. This ensures no superfluous software is installed or enabled by default.

Outdated APIs

Priority: high. APIs are frequently exploited by attackers to exfiltrate large volumes of sensitive data, and to gain initial access into the organization. In 2024, the number of API-related attacks increased by 41%, with attackers specifically targeting outdated APIs, as these often provide data with fewer checks and restrictions. This was exemplified by the leak of 200 million records from X/Twitter.

Prevalence: high. When a service transitions to a new API version, the old one often remains operational for an extended period, particularly if it’s still used by customers or partners. These deprecated versions are typically no longer maintained, so security flaws and vulnerabilities in their components go unpatched.

Detection: at the WAF or NGFW level, it’s essential to monitor traffic to specific APIs. This helps detect anomalies that may indicate exploitation or data exfiltration, and also identify APIs that get minimal traffic.

Response: for the identified low-activity APIs, collaborate with business stakeholders to develop a decommissioning plan, and migrate any remaining users to newer versions.

For organizations with a large pool of services, this challenge is best addressed with an API management platform in conjunction with a formally approved API lifecycle policy. This policy should include well-defined criteria for deprecating and retiring outdated software interfaces.

Software with outdated dependencies and libraries

Priority: high. This is where large-scale, critical vulnerabilities like Log4Shell hide, leading to organizational compromise and regulatory compliance issues.

Prevalence: Very high, especially in large-scale enterprise management systems, industrial automation systems, and custom-built software.

Detection: use a combination of vulnerability management (VM/CTEM) systems and software composition analysis (SCA) tools. For in-house development, it’s mandatory to use scanners and comprehensive security systems integrated into the CI/CD pipeline to prevent software from being built with outdated components.

Response: company policies must require IT and development teams to systematically update software dependencies. When building internal software, dependency analysis should be part of the code review process. For third-party software, it’s crucial to regularly audit the status and age of dependencies.

For external software vendors, updating dependencies should be a contractual requirement affecting support timelines and project budgets. To make these requirements feasible, it’s essential to maintain an up-to-date software bill of materials (SBOM).

You can read more about timely and effective vulnerability remediation in a separate blog post.

Forgotten websites

Priority: medium. Forgotten web assets can be exploited by attackers for phishing, hosting malware, or running scams under the organization’s brand, damaging its reputation. In more serious cases, they can lead to data breaches, or serve as a launchpad for attacks against the given company. A specific subset of this problem involves forgotten domains that were used for one-time activities, expired, and weren’t renewed — making them available for purchase by anyone.

Prevalence: high — especially for sites launched for short-term campaigns or one-off internal activities.

Detection: the IT department must maintain a central registry of all public websites and domains, and verify the status of each with its owners on a monthly or quarterly basis. Additionally, scanners or DNS monitoring can be utilized to track domains associated with the company’s IT infrastructure. Another layer of protection is provided by threat intelligence services, which can independently detect any websites associated with the organization’s brand.

Response: establish a policy for scheduled website shutdown after a fixed period following the end of its active use. Implement an automated DNS registration and renewal system to prevent the loss of control over the company’s domains.

Unused network devices

Priority: high. Routers, firewalls, surveillance cameras, and network storage devices that are connected but left unmanaged and unpatched make for the perfect attack launchpad. These forgotten devices often harbor vulnerabilities, and almost never have proper monitoring — no EDR or SIEM integration — yet they hold a privileged position in the network, giving hackers an easy gateway to escalate attacks on servers and workstations.

Prevalence: medium. Devices get left behind during office moves, network infrastructure upgrades, or temporary workspace setups.

Detection: use the same network inventory tools mentioned in the forgotten servers section, as well as regular physical audits to compare network scans against what’s actually plugged in. Active network scanning can uncover entire untracked network segments and unexpected external connections.

Response: ownerless devices can usually be pulled offline immediately. But beware: cleaning them up requires the same care as scrubbing servers — to prevent leaks of network settings, passwords, office video footage, and so on.