Cylance: Cybercrime put malicious code embedded within WAV audio files. Some contain code associated with the XMRig Monero CPU miner. Others included Metasploit
Beware if you download or share audo files, cybercrime put malicious code embedded within WAV audio files. It has been discovered by Cylance cyber security experts. Each WAV file was coupled with a loader component for decoding and executing malicious content secretly woven throughout the file’s audio data. When played, some of the WAV files produced music that had no discernible quality issues or glitches. Others simply generated static (white noise). Some of them contain code associated with the XMRig Monero CPU miner. Others included Metasploit code used to establish a reverse shell. Both payloads were discovered in the same environment, suggesting a two-pronged campaign to deploy malware for financial gain and establish remote access within the victim network.
The cyber security experts: the WAV file loaders can be grouped into three categories: one that use steganography to decode-execute PE file, the other to decode and execute a PE file and shellcode
According to the cyber security experts, the WAV file loaders can be grouped into three categories: Loaders that employ Least Significant Bit (LSB) steganography to decode and execute a PE file; Loaders that employ a rand()-based decoding algorithm to decode and execute a PE file, and Loaders that employ rand()-based decoding algorithm to decode and execute shellcode. Each approach allows the cybercrime to execute code from an otherwise benign file format. These techniques demonstrate that executable content could theoretically be hidden within any file type, provided the attacker does not corrupt the structure and processing of the container format. Adopting this strategy introduces an additional layer of obfuscation because the underlying code is only revealed in memory, making detection more challenging.
The steganography loader is also identified in Symantec’s June 2019 analysis of Waterbug/Turla threat actor activity
Moreover, the steganography loader Cylance cyber security experts discovered is also identified in Symantec’s June 2019 analysis of Waterbug/Turla threat actor activity. In addition, Symantec identified WAV files containing encoded Metasploit code. These similarities may point to a relationship between the attacks, though definitive attribution is challenging because different threat actors may use similar tools.