Description

A recently uncovered new malware campaign conducted by the Romanian-speaking threat group Diicot, also known as Mexals, uses advanced techniques in attacking Linux environments. It has expanded beyond the scope of the previous attacks, as earlier they only focused on cryptojacking. The campaign is now employing far more sophisticated methods, such as the Zephyr protocol for Monero mining and improved C2 infrastructure. This new malware brings changes in notable aspects, including the shift from using Discord-based C2 to HTTP and improved obfuscation, which makes it much harder for traditional security tools to detect the threat. This campaign is one of the most concerning due to its tailored approach, changing based on the environment it infects. Malware spreads in the cloud to other hosts. In regular setups, it uses the cryptomining payloads. This feature depends on the distribution of and Linux version on the remote machine. It gives an impression that the whole attack is rather strongly targeted. Apart from payload like Brute-Spreader supporting spreading of malware, Reverse Shell (client.go), used by it, for maintaining remote access to affected machines. The campaign first breaks in using weak SSH credentials and misconfigurations of security on systems, especially those with OpenSSH, to gain entry inside the network. Inside, cryptojacking tools are deployed, and more than $16,000 has been pocketed solely from Monero mining, besides the money made in other ways that cannot be easily traced with the Zephyr protocol. Besides monetary damage, data exfiltration and system compromise are among the critical risks, including operational disruptions. Wiz Research, therefore suggests that organizations enhance their SSH configuration, implement stronger passwords and employ more advanced detection tools that can detect obfuscated malware. As the capabilities of Diicot increase, so should the security strategies in response to this development in the group.