Security researchers at Cisco Talos recently uncovered attempts by malware attackers to test a publicly announced exploit targeting a recently discovered zero-day vulnerability in the Microsoft Windows Installer.

The vulnerability is a local privilege escalation vulnerability, known as CVE-2021-41379, and was discovered as a bypass to a Microsoft patch released in November.

Nick Biasini, head of outreach of Cisco Talos, highlighted the vulnerability and attempted move of attackers and pointed out that the attempts are part of a small-scale attack. Biasini also showed that such attempts are likely focused on testing and modifying exploits to launch full-blown malware campaigns.

“Since the volume is low, this is likely people working with the proof of concept code or testing for future campaigns. This is just more evidence on how quickly adversaries work to weaponize a publicly available exploit.”

Once the vulnerability has been successfully exploited, it gives attackers SYSTEM privileges on updated devices. A Microsoft spokesperson assured that the company is now working to fix the issue.