tThis botnet, exhibiting wormable self-spreader capabilities and an SSH key backdoor, has caught the attention of security researchers. NoaBot utilizes an SSH scanner to search for servers susceptible to dictionary attacks, allowing it to brute-force and gain remote access by adding an SSH public key. The botnet, compiled with uClibc, distinguishes itself by changing how antivirus engines detect the malware, with signatures appearing as an SSH scanner or a generic trojan rather than the typical Mirai signature.
Despite its Mirai foundations, NoaBot differentiates itself by incorporating an SSH scanner into its spreader module, a technique that enhances its ability to propagate. The attack chain employs obfuscation tactics, rendering analysis challenging for security experts. Moreover, NoaBot deploys a modified version of the XMRig coin miner. Notably, this variant stands out as it lacks information about the mining pool or wallet address, making it difficult to assess the profitability of the illicit cryptocurrency mining scheme.
The NoaBot campaign appears to be linked to another involving the P2PInfect Rust-based malware family. In recent attacks, threat actors experimented with replacing NoaBot with P2PInfect, indicating potential attempts to pivot to custom malware. NoaBot’s obfuscation tactics and the absence of mining pool and wallet address information contribute to its elusive nature. With 849 identified victim IP addresses spread globally, particularly concentrated in China, this Mirai variant underscores the ongoing challenge of securing networks against SSH credential dictionary attacks and emphasizes the importance of restricting arbitrary SSH access for enhanced cybersecurity.
