The faucet-estry of threats concentrating on Hamster Kombat gamers

Prior to now few months, the Telegram clicker sport Hamster Kombat has taken the world of cryptocurrency sport fans by storm. Though the gameplay, which largely entails repeatedly tapping the display screen of 1’s cellular system, may be reasonably easy, gamers are after one thing extra: the potential for incomes massive as soon as Hamster Kombat’s creators unveil the promised new cryptocoin tied to the sport.

Because of its success, the sport has already attracted numerous copycats that replicate its identify and icon, and have comparable gameplay. Fortunately, all of the early examples we discovered weren’t malicious, however nonetheless intention to make cash from in-app ads.

Sadly, ESET researchers found that cybercriminals have additionally began to capitalize on Hamster Kombat’s reputation. Exposing the dangers of attempting to acquire video games and associated software program from unofficial sources, we discovered a number of threats abusing Hamster Kombat’s fame in such locations as remotely managed Android malware distributed by way of an unofficial Hamster Kombat Telegram channel, pretend app shops that ship undesirable ads, and GitHub repositories distributing Lumma Stealer for Home windows gadgets whereas claiming to supply automation instruments for the sport.

Key factors of the blogpost:

• Hamster Kombat’s success has attracted malicious actors attempting to abuse curiosity within the sport for financial acquire.
• ESET researchers found Android spyware and adware named Ratel pretending to be Hamster Kombat, distributed by way of an unofficial Telegram channel.
• Android customers are additionally focused by pretend app shops claiming to supply the sport however delivering undesirable ads as an alternative.
• Home windows customers can encounter GitHub repositories providing farm bots and auto clickers that really include Lumma Stealer cryptors.

What’s Hamster Kombat?

Hamster Kombat is an in-app Telegram clicker sport the place the gamers earn fictional forex by finishing easy duties, with incentives to log into the sport no less than day by day. As in different cellular clicker video games, the essential gameplay of Hamster Kombat entails tapping the display screen repeatedly to attain extra in-game factors. A screenshot illustrating the sport’s interface will be seen in Determine 1.

Launched in March 2024, Hamster Kombat appears to be gaining in reputation fairly rapidly. In June 2024, the builders claimed that their sport had already managed to achieve 150 million energetic customers. Seeing as this could put Hamster Kombat – a sport aimed simply on the cryptocurrency fanatic subset of cellular avid gamers, and accessible solely by way of Telegram – within the prime 20 most-played cellular video games of all time, the declare ought to be taken with a grain of salt. Nonetheless, the sport is undoubtedly widespread: the official Hamster Kombat account on X has greater than 10 million followers, and the Hamster Kombat Announcement channel has greater than 50 million subscribers as of the publication of this blogpost.

Unsurprisingly, the primary motive behind the quickly rising curiosity in Hamster Kombat is the gamers’ need to earn cash by taking part in the sport: Hamster Kombat’s improvement roadmap consists of plans for launching a brand new cryptocoin token tied to the sport. The token ought to subsequently be distributed to the gamers based mostly on assembly sure standards, a method also called an airdrop.

The crew behind Hamster Kombat appears to be attempting to copy the success of one other Telegram-based sport known as Notcoin, which in Might 2024 launched the NOT token on Telegram’s blockchain platform The Open Community (TON) and airdropped it to the gamers based mostly on their in-game scores. NOT token’s launch was very profitable, with some claiming it was the largest crypto-gaming-token launch of 2024 thus far.

The Hamster Kombat token drop can be supposed to make use of the TON community. Versus Notcoin, nonetheless, the variety of tokens obtained will not rely on complete rating however on different components, comparable to profit-per-hour.

Risk evaluation

As any undertaking promising earnings for little effort, the sport itself can be on the radar of cybersecurity specialists and authorities officers, who’re warning of potential monetary dangers concerned in taking part in. Thus far, ESET has not seen any malicious exercise from the unique app.

Android threats

We recognized and analyzed two kinds of threats concentrating on Android customers: a malicious app that incorporates the Android spyware and adware Ratel and faux web sites that impersonate app retailer interfaces claiming to have Hamster Kombat accessible for obtain.

Ratel spyware and adware

ESET researchers discovered a Telegram channel (https://t[.]me/hamster_easy) distributing Android spyware and adware, named Ratel, disguised as Hamster Kombat; see Determine 2.

This malware is able to stealing notifications and sending SMS messages. The malware operators use this performance to pay for subscriptions and companies with the sufferer’s funds with out the sufferer noticing.

Whereas the malicious app misuses the identify Hamster Kombat to draw potential victims, it incorporates no performance discovered throughout the sport and even lacks a person interface altogether. As displayed in Determine 3, upon startup, the app requests notification entry permission, and asks to be set because the default SMS software. As soon as these permissions are granted, the malware will get entry to all SMS messages and is ready to intercept all displayed notifications.

Ratel then initiates communication with its C&C server (http://77.91.124[.]14:260), and as a response, receives a cellphone quantity: see Determine 4. Afterwards, it sends an SMS message with the textual content Привет! Набери мне: logID (translation: Hi there! Name me) to the that cellphone quantity, which most probably belongs to the malware operators.

The risk actors then turn into able to controlling the compromised system by way of SMS: the operator message can include a textual content to be despatched to a specified quantity, and even instruct the system to name the quantity. The malware can be capable of test the sufferer’s present banking account stability for Sberbank Russia by sending a message with the textual content баланс (translation: stability) to the quantity 900. That is most likely carried out with a view to determine whether or not the operators ought to pursue additional assault situations to entry the sufferer’s funds.

Ratel additionally abuses notification entry permissions to cover notifications from over 200 apps based mostly on a hardcoded record (see the Appendix for the whole record). The record incorporates apps comparable to Telegram, WhatsApp, and several other SMS messaging apps. If the affected system receives a notification from an app on the record, the sufferer will be unable to see it. Hiding is the one motion the malware does with these notifications; they aren’t forwarded to the C&C server. Almost definitely, the aim of intercepting the notifications is to stop the sufferer from discovering affirmation messages despatched by subscription companies.

As proven in Determine 5, in case there’s a notification from an app not included within the record, Ratel lets the person see it, whereas additionally forwarding it to the C&C server. We expect this may be carried out in order that the operators can test whether or not a brand new app must be added to the record.

Pretend web sites

In addition to the app with the Ratel spyware and adware, we additionally found pretend software storefronts claiming to supply Hamster Kombat for obtain. Nonetheless, tapping the Set up or Open buttons solely leads the person to undesirable ads. Examples of the pretend web sites will be present in Determine 6.

Home windows threats

Though Hamster Kombat is a cellular sport, we additionally discovered malware abusing the sport’s identify to unfold on Home windows. Cybercriminals attempt to entice Home windows customers with auxiliary instruments that declare to make maximizing in-game income simpler for the gamers. Our analysis revealed GitHub repositories (see Determine 7) providing Hamster Kombat farm bots and autoclickers, that are instruments that automate clicks in a sport. These repositories really turned out to hide cryptors from the notorious Lumma Stealer malware.

Lumma Stealer is an infostealer supplied as malware-as-a-service, accessible for buy on the darkish net and on Telegram. First noticed in 2022, this malware is usually distributed by way of pirated software program and spam, and targets cryptocurrency wallets, person credentials, two-factor authentication browser extensions, and different delicate data. Notice that Lumma Stealer’s capabilities should not lined by the MITRE ATT&CK matrix on this blogpost, for the reason that focus is on the cryptors that ship this infostealer, not on the infostealer itself.

The GitHub repositories we discovered both had the malware accessible instantly within the launch recordsdata, or contained hyperlinks to obtain it from exterior file-sharing companies. We recognized three totally different variations of Lumma Stealer cryptors lurking throughout the repositories: C++ purposes, Go purposes, and Python purposes. Of the three, solely the Python purposes have a graphical person interface (GUI).

C++ purposes

Within the case of the C++ purposes, Lumma Stealer is encrypted by way of the RC4 cipher and embedded within the executable the sufferer downloads. As soon as executed, the applying injects Lumma Stealer into the newly created course of C:WindowsMicrosoft.NETFrameworkv4.0.30319RegAsm.exe.

Go purposes

For the Go purposes, Lumma Stealer can be embedded within the executable, however this time, it’s encrypted utilizing AES-GCM. The cryptor makes use of copied and obfuscated code from go_libpeconv, a Go library for loading PE recordsdata, to do course of hollowing on the primary file discovered with the .exe extension beneath the C:Home windows listing.

Python purposes

The Python purposes have been both bundled with PyInstaller or compiled with Nuitka. When the sufferer runs the file downloaded from the GitHub repository, a pretend installer window with an I agree button seems, as will be seen in Determine 8. Upon clicking the button, this system connects to an FTP server and downloads a password-protected ZIP archive (password: crypto123) containing the cryptor with Lumma Stealer embedded. We discovered C++ and Go cryptors on the FTP server, which leads us to the conclusion that these purposes are in all probability totally different variations of the identical malware household.

As soon as the window is closed, the cryptor sends the C&C server the timestamps of when the sufferer clicked on the I agree button and when the malware was run. This information is distributed solely as soon as and there’s no additional C&C communication involving the cryptor. As proven in Determine 9, we discovered a remark report back to telegramm [sic] within the Python supply code of the malware, which means that in all probability the information is distributed from the C&C to the operators’ Telegram account or channel in some unspecified time in the future.

Conclusion

Hamster Kombat’s reputation makes it ripe for abuse, which implies that it’s extremely probably that the sport will appeal to extra malicious actors sooner or later. Whereas many copycat Hamster Kombat apps look like malware-free, we found a remotely managed trojan distributed by way of Telegram disguised as the sport. The malware is able to sending SMS messages, making calls, and concealing its actions by hiding notifications which may recommend the system is compromised. Aside from the Android trojan, we additionally discovered pretend app shops claiming to supply Hamster Kombat for obtain; the hyperlinks, nonetheless, usually result in undesirable ads. Lastly, on the Home windows platform, we uncovered GitHub repositories that lure avid gamers in with the promise of Hamster Kombat farm bots and autoclickers however that, in actuality, serve the victims with cryptors containing Lumma Stealer.

Due to Anton Cherepanov for his contributions.

For any inquiries about our analysis printed on WeLiveSecurity, please contact us at threatintel@eset.com

ESET Analysis presents non-public APT intelligence stories and information feeds. For any inquiries about this service, go to the ESET Risk Intelligence web page.

IoCs

A complete record of Indicators of Compromise (IoCs) and samples will be present in our GitHub repository.

Information

Community

Code-signing certificates

MITRE ATT&CK methods

This desk was constructed utilizing model 15 of the MITRE ATT&CK cellular methods.

This desk was constructed utilizing model 15 of the MITRE ATT&CK cellular methods.

Appendix

Following is the record of purposes from which the Ratel malware hides notifications: