Cybersecurity researchers have uncovered an ongoing cyber-attack against Ukraine that leverages a nearly seven-year-old flaw in Microsoft Office. The vulnerability, identified as CVE-2017-8570, enables remote code execution and has been used to deliver Cobalt Strike malware onto compromised systems through a PowerPoint slideshow file. The file, named to imply it was shared via the Signal app, acts as the entry point for these attacks, though there is no direct evidence linking its distribution to this platform.
The attack utilizes the PowerPoint file, which pretends to be an instruction manual for U.S. Army tank mine clearing blades, to execute a remote script. This script sets up persistence on the infected host and deploys a payload disguised as the Cisco AnyConnect VPN client. This payload includes a dynamic-link library (DLL) that injects a cracked version of Cobalt Strike Beacon into the system’s memory, awaiting commands from a remote command-and-control server.
The sophistication of the attack extends to the DLL’s ability to detect if it’s running in a virtual machine, a common tactic used to evade detection by security software. The actual distribution mechanism and ultimate goals of the intrusion remain unclear, with researchers unable to conclusively link these activities to any specific threat actor or verify whether it might be part of a red teaming exercise. The domains used in the attack, disguised as benign websites, add an additional layer of obfuscation.
