CVE-2020-3432 is a vulnerability that affects the uninstaller component of Cisco AnyConnect Secure Mobility Client for macOS. This vulnerability arises from the incorrect handling of directory paths, allowing an attacker to corrupt the content of any file in the file system. If the targeted file is a critical system file, the exploit could lead to a denial of service (DoS) condition. It is important to note that to exploit this vulnerability, the attacker must have valid credentials on the target system.

In this blog post, we will discuss the technical details of this vulnerability, provide a code snippet to demonstrate the exploit, and share links to original references for further reading.

Exploit Details

The root cause of this vulnerability (CVE-2020-3432) is an issue in the handling of directory paths by the uninstaller component of Cisco AnyConnect Secure Mobility Client for macOS. The exploit involves an attacker creating a symbolic link (symlink) to a target file, which leads to the corruption of the file's contents. This is possible because the uninstaller component does not properly sanitize the directory paths during the uninstallation process.

Here is a code snippet demonstrating how an attacker could create a symlink to exploit this vulnerability:

// The attacker creates a symlink pointing to a target file
$ ln -s /target/file/path /path/to/anyconnect/uninstaller

// Execute the uninstaller, which corrupts the target file
$ /path/to/anyconnect/uninstaller

If the attacker were to target a critical system file, the successful exploitation of this vulnerability could result in a denial of service condition.

1. The official Cisco advisory on CVE-2020-3432 can be found here: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-anyconnect-dos-YVzegXPb

2. The CVE details, including affected versions and CVSS score, are available here: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-3432

3. The official National Vulnerability Database entry for CVE-2020-3432: https://nvd.nist.gov/vuln/detail/CVE-2020-3432

Mitigation Measures

Cisco has released software updates to address this vulnerability. It is strongly recommended to update your Cisco AnyConnect Secure Mobility Client for macOS to the latest version. Additionally, you can implement security best practices, such as strong access controls and user permissions, to reduce the likelihood of an attacker gaining valid credentials on the target system.

Conclusion

CVE-2020-3432 is a significant vulnerability that, if exploited, can lead to the corruption of files and potential denial of service conditions on macOS systems running Cisco AnyConnect Secure Mobility Client. It is important to understand the details of this vulnerability and follow the recommended mitigation measures to protect your systems from potential attacks.

Timeline

Published on: 02/12/2025 00:15:07 UTC
Last modified on: 02/12/2025 15:15:10 UTC