Proof-of-concept exploit code has been disclosed for a significant vulnerability in Cisco Secure Client Software for Windows, previously known as AnyConnect Secure Mobility Client. This flaw, identified as CVE-2023-20178, allows authenticated threat actors to escalate privileges to the SYSTEM account, a crucial account in the Windows operating system.
The exploit does not require complex attacks or user interaction, making it a high-severity issue. Cisco has addressed the vulnerability with security updates released for AnyConnect Secure Mobility Client for Windows 4.10MR7 and Cisco Secure Client for Windows 5.0MR2. The company’s Product Security Incident Response Team (PSIRT) mentioned that there is no evidence of malicious use or public exploit code in the wild as of now. The vulnerability involves abusing a specific function of the Windows installer process. Security researcher Filip Dragović discovered and reported the Arbitrary File Delete vulnerability to Cisco. The proof-of-concept exploit, tested on Cisco Secure Client (5.0.01242) and Cisco AnyConnect (4.10.06079), takes advantage of the vpndownloader.exe process created when a user connects to the VPN.
This process, operating in the background, manipulates directories in a way that can be exploited to perform arbitrary file deletion, ultimately escalating privileges to the NT Authority\SYSTEM account. Cisco urges users to apply the security updates promptly to mitigate the risk of potential exploitation. This disclosure follows Cisco’s recent warnings to customers regarding the patching of two additional security flaws in AnyConnect, emphasizing the importance of keeping VPN software up-to-date to guard against potential vulnerabilities that could be exploited by malicious actors.
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