Cisco AnyConnect Vulnerability: A High-Severity Flaw Exposed

Recently, a high-severity flaw in Cisco Secure Client Software for Windows, formerly known as AnyConnect Secure Mobility Client, has come to light. This vulnerability, identified as CVE-2023-20178, allows authenticated threat actors to escalate privileges to the SYSTEM account in Windows without any user interaction.

The exploit takes advantage of a specific function of the Windows installer process and manipulates the behavior of the vpndownloader.exe process. The vulnerability exists due to improper permissions assigned to a temporary directory created during the update process. An attacker could exploit this vulnerability by misusing a specific function of the Windows installer process. A successful exploit could enable the attacker to execute code with SYSTEM privileges.

Despite Cisco's release of security updates to address this bug, a proof-of-concept exploit code has been published by a security researcher. The exploit was tested on Cisco Secure Client (version 5.0.01242) and Cisco AnyConnect (version 4.10.06079). By deleting arbitrary files, the attacker can spawn a SYSTEM shell and escalate privileges.

The exposure of this Cisco AnyConnect vulnerability is concerning, especially given the past instances of active exploitation of AnyConnect security flaws, which had prompted Cisco to issue patches. This incident underscores the importance of maintaining up-to-date security measures and highlights the potential risks associated with vulnerabilities in widely used software like Cisco AnyConnect.

In response to the vulnerability, Cisco has released software updates that address this security issue. However, there are no workarounds that address this vulnerability. According to the Cisco Product Security Incident Response Team (PSIRT), there was no evidence of malicious use or public exploit code targeting the bug in the wild at the time of the security updates release.

Users are advised to update their software to the latest version to protect against this vulnerability and to follow best practices for cybersecurity to safeguard their systems and data.