The threat group tracked as Evilnum was observed using updated tactics and tools in recent attacks, Cybereason’s Nocturnus research team reported last week.
Initially detailed in 2018, Evilnum appears to have been active for nearly a decade, offering ‘mercenary’ hack-for-hire services, a recent report from Kaspersky revealed.
Focused on espionage, Evilnum recently switched from delivering ZIP archives containing multiple LNK files (via spear-phishing) to including a single LNK in the archive, which masquerades as a PDF, Cybereason reveals. Once executed, the shortcut writes to disk a JavaScript that replaces the LNK with the actual PDF.
Furthermore, the hackers have adopted a scheduled task to ensure persistence, moving away from the previously used Run registry key. The scheduled task retrieves and executes the next stage payload, a modified version of “Java Web Start Launcher.”
This payload, however, was designed as a downloader for the next stage, another downloader that instead fetches the final payload and runs it directly in memory, with a scheduled task named “Adobe Update Task.”
Dubbed PyVil RAT and written in Python, the delivered malware was designed to log keystrokes, run cmd commands, take screenshots, download additional Python scripts to expand functionality, drop and upload executables, open an SSH shell, and collect system information (running antivirus program, connected USB devices, Chrome version).
The malware communicates with its command and control (C&C) server via HTTP POST requests that are RC4-encrypted.
Cybereason’s security researchers also observed PyVil RAT receiving from the C&C a custom version of the LaZagne Project, which was employed by ..
Support the originator by clicking the read the rest link below.
