Cado researchers have uncovered evidence of an evolving cyber threat posed by the Diicot (formerly known as “Mexals”) cybercrime group. This emerging group, traditionally associated with cryptojacking campaigns, has expanded its capabilities with the deployment of the Cayosin Botnet. The researchers identified several previously unknown payloads being utilized in an ongoing campaign.
Notably, the use of Romanian-language elements and the name Diicot, associated with a Romanian policing unit, suggest the group’s potential origin in Romania. The cybercrime group, known for its cryptojacking activities, surprised analysts by deploying the Cayosin bot, which specifically targeted routers running the Linux-based OpenWrt operating system. The Diicot threat actors demonstrated distinctive Tactics, Techniques, and Procedures (TTPs) throughout the attack chain. Their techniques include heavy use of the Shell Script Compiler (shc) and a custom version of the UPX packer.
Discord served as a Command and Control (C2) platform, utilizing HTTP POST requests to a webhook URL for data exfiltration and campaign statistics. Cado identified four distinct channels employed by Diicot in this campaign. The attack chain is intricate, involving a series of stages, with the final stage revealing a Monero cryptominer. The initial access point for the campaign was observed through a custom SSH brute-forcing tool named aliases. Cado Labs recommended measures to defend against Diicot’s malware family, advising users to implement basic SSH hardening practices. This includes enforcing key-based authentication for SSH instances and implementing firewall rules to restrict SSH access to specific IP addresses. The report underscores the Diicot group’s emergence as a significant cyber threat with diverse objectives and the technical knowledge to carry them out.
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