Attackers leveraged Microsoft Exchange vulnerabilities ProxyShell and ProxyLogon as an initial attack vector to deploy COLDDRAW ransomware, publicly known as Cuba ransomware.
To a great extent, the ransomware gang uses commodity and custom malware and a variety of backdoors to establish its foothold on the target network.
These include malware and utilities such as Cobalt Strike beacon, NetSupport, Mimikatz, RDP, SMB, PsExec, Wicker, and Termite, as well as its exclusive tools Bughatch, Wedgecut, eck.exe, and Burntcigar.
The CHANITOR connection
Mandiant has observed overlaps between CHANITOR (aka Hancitor) malware-related operations and Cuba incidents, including infrastructure overlaps, common code signing certificates, use of a shared packer, and naming similarities for domains, files, and URLs paths.
Conclusion
The exploitation of known vulnerabilities offers the threat actors more accurate targeting and higher success rates in their operations. A sophisticated group like UNC2596 may shift its focus to other vulnerabilities and can also draw the attention of other hacking groups toward this trend. Users can create barriers for potential attacks by applying the available security updates as soon as the software vendors release them.