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Koske: An AI-Generated Linux Malware Emerges in the Cyber Threat Landscape

Koske, an advanced AI-generated Linux malware, poses significant threats with its sophisticated techniques and AI-driven capabilities.

Koske: An AI-Generated Linux Malware Emerges in the Cyber Threat Landscape

TL;DR

Koske, a newly discovered AI-generated Linux malware, employs sophisticated techniques like rootkits and polyglot image file abuse for cryptomining. Attackers exploit misconfigured servers to deliver payloads hidden in image files, making detection challenging. This malware highlights the evolving landscape of AI-assisted cyber threats.

Koske: An AI-Generated Linux Malware Emerges in the Cyber Threat Landscape

Introduction

Koske, a newly identified Linux malware, is believed to be developed with the aid of artificial intelligence for cryptomining activities. Researchers at AquaSec have reported that this malicious code utilizes advanced techniques such as rootkits and polyglot image file abuse to evade detection1.

Exploitation and Delivery Methods

Attackers exploit misconfigured servers to drop backdoors and download two JPEG polyglot files via shortened URLs. These images are polyglot files that conceal malicious code appended at the end, which executes directly in memory to bypass antivirus detection. One file is a C code compiled into a rootkit .so file, while the other is a stealthy shell script using standard system tools to persist without leaving visible traces1.

Techniques and Tactics

The malware’s main and secondary payloads are delivered through dual-use image files. Threat actors embed malicious shell scripts within legitimate image files, such as pictures of panda bears, which are stored on legitimate and free image storage platforms like freeimage, postimage, and OVH images2.

This technique is not steganography but rather polyglot file abuse or malicious file embedding. It involves appending malicious shellcode to a valid JPG file, with only the last bytes being downloaded and executed. This method blends image data with executable payloads, making it a dual-use file that evades detection1.

Koske Malware

Attackers gain initial access through a misconfigured JupyterLab instance and ensure persistence by hijacking shell configs and boot processes to run stealthy scripts1.

AI-Like Behavior and Attribution

Koske exhibits AI-like behavior in its connectivity module, employing multiple methods to test GitHub access, fix issues by resetting DNS and proxies, and dynamically brute-force working proxies. This adaptive and automated strategy suggests AI-assisted development1.

Several components of the script indicate the involvement of Large Language Models (LLMs):

  • Verbose, well-structured comments and modularity
  • Best-practice logic flow with defensive scripting habits
  • Obfuscated authorship using Serbian phrases and neutralized syntax

Such code may have been designed to appear generic, frustrating attribution and analysis1.

Cryptomining Capabilities

Koske supports mining 18 different cryptocurrencies, selecting CPU- or GPU-optimized miners based on the infected host’s hardware. It automatically switches coins or pools if one fails, targeting assets like Monero, Ravencoin, Zano, Nexa, and Tari1.

AquaSec discovered Serbian IPs, Serbian script phrases, and Slovak language in the miners’ GitHub repo but could not confidently attribute the attacks1.

Implications and Future Threats

The use of AI to generate better code poses significant challenges for defenders. AI-powered malware, which dynamically interacts with AI models to adapt its behavior in real-time, could mark a substantial leap in adversaries’ tactics, putting countless systems at serious risk1.

Conclusion

Koske represents a new era of AI-generated malware, highlighting the need for advanced detection and mitigation strategies. As AI continues to evolve, so will the sophistication of cyber threats, requiring constant vigilance and innovation from cybersecurity professionals.

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References

  1. AquaSec (2025). “AI-Generated Malware in Panda Image Hides Persistent Linux Threat”. AquaSec Blog. Retrieved 2025-07-25. ↩︎ ↩︎2 ↩︎3 ↩︎4 ↩︎5 ↩︎6 ↩︎7 ↩︎8 ↩︎9

  2. freeimage (2025). “Free Image Hosting”. Freeimage. Retrieved 2025-07-25. ↩︎

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