Rare AutoCAD malware rigs drafting machines for follow-up attacks
Security researchers have discovered a rare strain of AutoCAD malware that opens up compromised machines to secondary exploits.
ACM/SHENZ-A poses as a legitimate component of AutoCAD software for computer-aided design (CAD). But analysis by security researchers at Trend Micro has revealed that the malicious file opens up systems to exploits, specifically those targeting old vulnerabilities. The .FAS file that's the carrier of the malware packs a malicious script.
The malware first creates a user account with administrative rights on the system before creating network shares for all drives on an infected computer. It then opens up four system ports (137-139, and port 445), communication channels associated with the Server Message Block (SMB) protocol that provides file, print and share functionality between nodes on Windows networks. The tactic thwarts restrictions on Windows networks applied by sysadmins designed to frustrate common types of hack attacks.
"By opening the ports, exploits that target SMB can successfully run on affected systems, provided that the relevant vulnerabilities have not yet been patched," explains Anthony Joe Melgarejo, a threat response engineer at Trend Micro, in a blog post about the attack. "Security bulletins that cover the SMB vulnerabilities include MS10-020 and MS11-043."