Attackers are constantly reinventing ways of monetizing their tools. Cisco Talos recently discovered a complex campaign employing a multi-modular botnet with multiple ways to spread and a payload focused on providing financial benefits for the attacker by mining the Monero online currency. The actor employs various methods to spread across the network, like SMB with stolen credentials, psexec, WMI and SMB exploits. The adversary also uses several crafted tools that helps the botnet increase the amount of systems participating in its Monero-mining pool.
The infection starts with the main botnet file which is copied from other infected systems by means of SMB, using passwords retrieved by a modified Mimikatz module and exploits such as Eternal Blue. The actor is also aware of the latest SMB vulnerabilities such as SMBGhost, but no evidence of using this exploit has been found.
The botnet has more than 15 executable modules that all get downloaded and driven by the main module, which constantly communicates with the command and control (C2) server over HTTP. However, the encrypted data is sent using RC4 encryption, and the module shares the key with the C2 using asymmetric encryption.
Apart from a large focus on spreading across the environment, Prometei also tries to recover administrator passwords. The discovered passwords are sent to the C2 and then reused by other modules that attempt to verify the validity of the passwords on other systems using SMB and RDP protocols.