The tap-estry of threats targeting Hamster Kombat players

Prior to now few months, the Telegram clicker recreation Hamster Kombat has taken the world of cryptocurrency recreation fans by storm. Though the gameplay, which principally entails repeatedly tapping the display of 1’s cell machine, is perhaps reasonably easy, gamers are after one thing extra: the potential for incomes large 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 related gameplay. Fortunately, all of the early examples we discovered weren’t malicious, however however intention to generate profits from in-app ads.

Sadly, ESET researchers found that cybercriminals have additionally began to capitalize on Hamster Kombat’s recognition. Exposing the risks of making an attempt 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 an unofficial Hamster Kombat Telegram channel, faux 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 making an attempt to abuse curiosity within the recreation for financial achieve.
• 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 faux 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 recreation the place the gamers earn fictional foreign money by finishing easy duties, with incentives to log into the sport at the least each day. As in different cell clicker video games, the essential gameplay of Hamster Kombat includes tapping the display repeatedly to attain extra in-game factors. A screenshot illustrating the sport’s interface could be seen in Determine 1.

Launched in March 2024, Hamster Kombat appears to be gaining in recognition fairly shortly. In June 2024, the builders claimed that their recreation had already managed to succeed in 150 million lively customers. Seeing as this might put Hamster Kombat – a recreation aimed simply on the cryptocurrency fanatic subset of cell players, and obtainable solely by Telegram – within the high 20 most-played cell video games of all time, the declare needs to be taken with a grain of salt. However, the sport is undoubtedly in style: 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 principle purpose behind the quickly rising curiosity in Hamster Kombat is the gamers’ want to earn cash by taking part in the sport: Hamster Kombat’s development 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 primarily based on assembly sure standards, a method often known as an airdrop.

The workforce behind Hamster Kombat appears to be making an attempt to duplicate the success of one other Telegram-based recreation referred to as Notcoin, which in Could 2024 launched the NOT token on Telegram’s blockchain platform The Open Community (TON) and airdropped it to the gamers primarily based on their in-game scores. NOT token’s launch was very successful, with some claiming it was the largest crypto-gaming-token launch of 2024 thus far.

The Hamster Kombat token drop can also be supposed to make use of the TON community. Versus Notcoin, nevertheless, the variety of tokens obtained will not depend on complete rating however on different elements, akin to profit-per-hour.

Risk evaluation

As was to be anticipated, the success of Hamster Kombat has additionally introduced out cybercriminals, who’ve already began to deploy malware concentrating on the gamers of the sport. ESET Analysis has uncovered threats going after each Android and Home windows customers. Android customers are focused by spyware and adware and pretend app shops filled with undesirable ads, whereas Home windows customers can encounter GitHub repositories with Lumma Stealer cryptors.

As any challenge promising earnings for little effort, the sport itself can also be on the radar of cybersecurity consultants 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 forms of threats concentrating on Android customers: a malicious app that comprises the Android spyware and adware Ratel and pretend web sites that impersonate app retailer interfaces claiming to have Hamster Kombat obtainable 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 comprises no performance discovered throughout the recreation 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: Hiya! Name me) to the that cellphone quantity, which most definitely belongs to the malware operators.

The menace actors then grow to be able to controlling the compromised machine by way of SMS: the operator message can include a textual content to be despatched to a specified quantity, and even instruct the machine to name the quantity. The malware can also be in a position to verify 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 likely performed with the intention to determine whether or not the operators ought to pursue additional assault eventualities to entry the sufferer’s funds.

Ratel additionally abuses notification entry permissions to cover notifications from over 200 apps primarily based on a hardcoded record (see the Appendix for the whole record). The record comprises apps akin to Telegram, WhatsApp, and several other SMS messaging apps. If the affected machine 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. Most definitely, the aim of intercepting the notifications is to forestall 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 predict this is perhaps performed in order that the operators can verify whether or not a brand new app must be added to the record.

Faux web sites

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

Home windows threats

Though Hamster Kombat is a cell recreation, 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 earnings 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 recreation. These repositories truly turned out to hide cryptors from the notorious Lumma Stealer malware.

Lumma Stealer is an infostealer supplied as malware-as-a-service, obtainable for buy on the darkish internet and on Telegram. First noticed in 2022, this malware is often distributed by way of pirated software program and spam, and targets cryptocurrency wallets, person credentials, two-factor authentication browser extensions, and different delicate info. Be aware 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 obtainable instantly within the launch recordsdata, or contained hyperlinks to obtain it from exterior file-sharing companies. We recognized three completely different variations of Lumma Stealer cryptors lurking throughout the repositories: C++ functions, Go functions, and Python functions. Of the three, solely the Python functions have a graphical person interface (GUI).

C++ functions

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

Go functions

For the Go functions, Lumma Stealer can also 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 process hollowing on the primary file discovered with the .exe extension beneath the C:Home windows listing.

Python functions

The Python functions have been both bundled with PyInstaller or compiled with Nuitka. When the sufferer runs the file downloaded from the GitHub repository, a faux installer window with an I agree button seems, as could 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 functions are most likely completely 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 knowledge 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, that means that most likely the info is distributed from the C&C to the operators’ Telegram account or channel in some unspecified time in the future.

Conclusion

Hamster Kombat’s recognition makes it ripe for abuse, which signifies that it’s extremely possible that the sport will appeal to extra malicious actors sooner or later. Whereas many copycat Hamster Kombat apps seem 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 counsel the machine is compromised. Other than the Android trojan, we additionally discovered faux app shops claiming to supply Hamster Kombat for obtain; the hyperlinks, nevertheless, typically result in undesirable ads. Lastly, on the Home windows platform, we uncovered GitHub repositories that lure players in with the promise of Hamster Kombat farm bots and autoclickers however that, in actuality, serve the victims with cryptors containing Lumma Stealer.

Because of Anton Cherepanov for his contributions.

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

ESET Analysis affords non-public APT intelligence studies and knowledge feeds. For any inquiries about this service, go to the ESET Threat Intelligence web page.

IoCs

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

Information

Community

Code-signing certificates

MITRE ATT&CK methods

This desk was constructed utilizing version 15 of the MITRE ATT&CK cell methods.

This desk was constructed utilizing version 15 of the MITRE ATT&CK cell methods.

Appendix

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