To achieve their malign aims, Android malware developers have to address several challenges in a row: trick users to get inside their smartphones, dodge security software, talk victims into granting various system permissions, keep away from built-in battery optimizers that kill resource hogs, and, after all that, make sure their malware actually turns a profit. The creators of the BeatBanker — an Android‑based malware campaign recently discovered by our experts — have come up with something new for each one of these steps. The attack is (for now) aimed at Brazilian users, but the developers’ ambitions will almost certainly push them toward international expansion, so it’s worth staying on guard and studying the threat actor’s tricks. You can find a full technical analysis of the malware on Securelist.

How BeatBanker infiltrates a smartphone

The malware is distributed through specially crafted phishing pages that mimic the Google Play Store. A page that’s easily mistaken for the official app marketplace invites users to download a seemingly useful app. In one campaign, the trojan disguised itself as the Brazilian government services app, INSS Reembolso; in another, it posed as the Starlink app.

The installation takes place in several stages to avoid requesting too many permissions at once and to further lull the victim’s vigilance. After the first app is downloaded and launched, it displays an interface that also resembles Google Play and simulates an update for the decoy app — requesting the user’s permission to install apps, which doesn’t look out-of-the-ordinary in context. If you grant this permission, the malware downloads additional malicious modules to your smartphone.

All components of the trojan are encrypted. Before decrypting and proceeding to the next stages of infection, it checks to ensure it’s on a real smartphone and in the target country. BeatBanker immediately terminates its own process if it finds any discrepancies or detects that it’s running in emulated or analysis environments. This complicates dynamic analysis of the malware. Incidentally, the fake update downloader injects modules directly into RAM to avoid creating files on the smartphone that would be visible to security software.

All these tricks are nothing new and frequently used in complex malware for desktop computers. However, for smartphones, such sophistication is still a rarity, and not every security tool will spot it. Users of Kaspersky products are protected from this threat.

Playing audio as a shield

Once established on the smartphone, BeatBanker downloads a module for mining Monero cryptocurrency. The authors were very concerned that the smartphone’s aggressive battery optimization systems might shut down the miner, so they came up with a trick: playing an all-but-inaudible sound at all times. Power consumption control systems typically spare apps that are playing audio or video to avoid cutting off background music or podcast players. In this way, the malware can run continuously. Additionally, it displays a persistent notification in the status bar, asking the user to keep the phone on for a system update.

Control via Google

To manage the trojan, the authors leverage Google’s legitimate Firebase Cloud Messaging (FCM) — a system for receiving notifications and sending data from a smartphone. This feature is available to all apps and it’s the most popular method for sending and receiving data. Thanks to FCM, attackers can monitor the device’s status and change its settings as needed.

Nothing bad happens for a while after the malware is installed: the attackers wait it out. Then they trigger the miner, but they’re careful to throttle it back if the phone overheats, the battery starts dipping, or the owner happens to be using the device. All of this is handled via FCM.

Theft and espionage

In addition to the crypto miner, BeatBanker installs extra modules to spy on the user and rob them at the right moment. The spyware module requests Accessibility Services permission, and if this is granted, begins monitoring everything that’s happening on the smartphone.

If the owner opens the Binance or Trust Wallet app to send USDT, the malware overlays a fake screen on top of the wallet interface, effectively swapping the recipient’s address for its own. All transfers go to the attackers.

The trojan features an advanced remote control system and is capable of executing many other commands:

• Intercepting one-time codes from Google Authenticator
• Recording audio from the microphone
• Streaming the screen in real-time
• Monitoring the clipboard and intercept keystrokes
• Sending SMS messages
• Simulating taps on specific areas of the screen and text input according to a script sent by the attacker, and much more

All of this makes it possible to rob the victim when they use any other banking or payment services — not just crypto payments.

Sometimes victims are infected with a different module for espionage and remote smartphone control — the BTMOB remote access trojan. Its malicious capabilities are even broader, including:

• Automatic acquisition of certain permissions on Android 13–15
• Continuous geolocation tracking
• Access to the front and rear cameras
• Obtaining PIN codes and passwords for screen unlocking
• Capturing keyboard input

How to protect yourself from BeatBanker

Cybercriminals are constantly refining their attacks and coming up with new ways to profit from their victims. Despite this, you can protect yourself by following a few simple precautions:

• Download apps from official sources only, such as Google Play or the app store preinstalled by the vendor. If you find an app while searching the internet, don’t open it via a link from your browser; instead, head to the Google Play app or another branded store on your smartphone to search for it there. While you’re at it, check the number of downloads, the app’s age, and look at the ratings and reviews. Avoid new apps, apps with low ratings, and those with a small number of downloads.
• Check any permissions you grant. Don’t grant permissions if you’re not sure what they do or why that specific app requires them. Be extra careful with permissions like Install unknown apps, Accessibility, Superuser, and Display over other apps. We’ve written about these in detail in a separate article.
• Equip your device with a comprehensive anti-malware solution. We, naturally, recommend Kaspersky for Android. Users of Kaspersky products are protected from BeatBanker — detected with the verdicts HEUR:Trojan-Dropper.AndroidOS.BeatBanker and HEUR:Trojan-Dropper.AndroidOS.Banker.*.
• Regularly update both your operating system and security software. For Kaspersky for Android, which is currently unavailable on Google Play, please review our detailed instructions on installing and updating the app.

Threats to Android users have been going through the roof lately. Check out our other posts on the most relevant and widespread Android attacks and tips for keeping you and your loved ones safe:

• The perfect storm of Android threats
• Brain drain: vulnerabilities in mental health apps
• Pixnapping vulnerability: unblockable screenshots of your Android phone
• NFC skimming attacks
• A new layer of anti-phishing security in Kaspersky for Android

In November 2025, Kaspersky experts uncovered a new stealer named Stealka, which targets Windows users’ data. Attackers are using Stealka to hijack accounts, steal cryptocurrency, and install a crypto miner on their victims’ devices. Most frequently, this infostealer disguises itself as game cracks, cheats and mods.

Here’s how the attackers are spreading the stealer, and how you can protect yourself.

How Stealka spreads

A stealer is a type of malware that collects confidential information stored on the victim’s device and sends it to the attackers’ server. Stealka is primarily distributed via popular platforms like GitHub, SourceForge, Softpedia, sites.google.com, and others, disguised as cracks for popular software, or cheats and mods for games. For the malware to be activated, the user must run the file manually.

Here’s an example: a malicious Roblox mod published on SourceForge.

And here’s one on GitHub posing as a crack for Microsoft Visio.

Sometimes, however, attackers go a step further (and possibly use AI tools) to create entire fake websites that look quite professional. Without the help of a robust antivirus, the average user is unlikely to realize anything is amiss.

Admittedly, the cracks and software advertised on these fake sites can sometimes look a bit off. For example, here the attackers are offering a download for Half-Life 3, while at the same time claiming it’s not actually a game but some kind of “professional software solution designed for Windows”.

The truth is that both the page title and the filename are just bait. The attackers simply use popular search terms to lure users into downloading the malware. The actual file content has nothing to do with what’s advertised — inside, it’s always the same infostealer.

The site also claimed that all hosted files were scanned for viruses. When the user decides to download, say, a pirated game, the site displays a banner saying the file is being scanned by various antivirus engines. Of course, no such scanning actually takes place; the attackers are merely trying to create an illusion of trustworthiness.

What makes Stealka dangerous

Stealka has a fairly extensive arsenal of capabilities, but its prime target is data from browsers built on the Chromium and Gecko engines. This puts over a hundred different browsers at risk, including popular ones like Chrome, Firefox, Opera, Yandex Browser, Edge, Brave, as well as many, many others.

Browsers store a huge amount of sensitive information, which attackers use to hijack accounts and continue their attacks. The main targets are autofill data, such as sign-in credentials, addresses, and payment card details. We’ve warned repeatedly that saving passwords in your browser is risky — attackers can extract them in seconds. Cookies and session tokens are perhaps even more valuable to hackers, as they can allow criminals to bypass two-factor authentication and hijack accounts without entering the password.

The story doesn’t end with the account hack. Attackers use these compromised accounts to spread the malware further. For example, we discovered the stealer in a GTAV mod posted on a dedicated site by an account that had previously been compromised.

Beyond stealing browser data, Stealka also targets the settings and databases of 115 browser extensions for crypto wallets, password managers, and 2FA services. Here are some of the most popular extensions now at risk:

• Crypto wallets: Binance, Coinbase, Crypto.com, SafePal, Trust Wallet, MetaMask, Ton, Phantom, Exodus
• Two-factor authentication: Authy, Google Authenticator, Bitwarden
• Password management: 1Password, Bitwarden, LastPass, KeePassXC, NordPass

Finally, the stealer also downloads local settings, account data, and service files from a wide variety of applications:

• Crypto wallets. Wallet configurations may contain encrypted private keys, seed-phrase data, wallet file paths, and encryption parameters. That’s enough to at least make an attempt at stealing your cryptocurrency. At risk are 80 wallet applications, including Binance, Bitcoin, BitcoinABC, Dogecoin, Ethereum, Exodus, Mincoin, MyCrypto, MyMonero, Monero, Nexus, Novacoin, Solar, and many others.
• Messaging apps. Messaging app service files store account data, device identifiers, authentication tokens, and the encryption parameters for your conversations. In theory, a malicious actor could gain access to your account and read your chats. At risk are Discord, Telegram, Unigram, Pidgin, Tox, and others.
• Password managers. Even if the passwords themselves are encrypted, the configuration files often contain information that makes cracking the vault significantly easier: encryption parameters, synchronization tokens, and details about the vault version and structure. At risk are 1Password, Authy, Bitwarden, KeePass, LastPass, and NordPass.
• Email clients. These are where your account credentials, mail server connection settings, authentication tokens, and local copies of your emails can be found. With access to your email, an attacker will almost certainly attempt to reset passwords for your other services. At risk are Gmail Notifier Pro, Claws, Mailbird, Outlook, Postbox, The Bat!, Thunderbird, and TrulyMail.
• Note-taking apps. Instead of shopping lists or late-night poetry, some users store information in their notes that has no business being there, like seed phrases or passwords. At risk are NoteFly, Notezilla, SimpleStickyNotes, and Microsoft StickyNotes.
• Gaming services and clients. The local files of gaming platforms and launchers store account data, linked service information, and authentication tokens. At risk are Steam, Roblox, Intent Launcher, Lunar Client, TLauncher, Feather Client, Meteor Client, Impact Client, Badlion Client, and WinAuth for battle.net.
• VPN clients. By gaining access to configuration files, attackers can hijack the victim’s VPN account to mask their own malicious activities. At risk are AzireVPN, OpenVPN, ProtonVPN, Surfshark, and WindscribeVPN.

That’s an extensive list — and we haven’t even named all of them! In addition to local files, this infostealer also harvests general system data: a list of installed programs, the OS version and language, username, computer hardware information, and miscellaneous settings. And as if that weren’t enough, the malware also takes screenshots.

How to protect yourself from Stealka and other infostealers

• Secure your device with reliable antivirus software. Even downloading files from legitimate websites is no guarantee of safety — attackers leverage trusted platforms to distribute stealers all the time. Kaspersky Premium detects malware on your computer in time and alerts you to the threat.
• Don’t store sensitive information in browsers. It’s handy — no one can argue with that. But unfortunately browsers aren’t the most secure environment for your data. Sign-in credentials, bank card details, secret notes, and other confidential information are better kept in a securely encrypted format in Kaspersky Password Manager, which is immune to the exploits used by Stealka.
• Be careful with game cheats, mods, and especially pirated software. It’s better to pay up for official software than to chase the false savings offered by software cracks, and end up losing all your money.
• Enable two-factor authentication or use backup codes wherever possible. Two-factor authentication (2FA) makes life much harder for attackers, while backup codes help you regain access to your critical accounts if compromised. Just be sure not to store backup codes in text documents, notes, or your browser. For all your backup codes and 2FA tokens, use a reliable password manager.

Curious what other stealers are out there, and what they’re capable of? Read more in our other posts:

• Beware of stealers disguised as… wedding invitations
• AMOS infostealer distributed via ChatGPT chat-sharing feature
• Banshee: A stealer targeting macOS users
• Arcane stealer instead of Minecraft cheats
• Efimer Trojan using hacked websites to steal cryptocurrency