CVE-2022-22582: A Deep Dive into the Validation Issue and Exploit in Handling Symlinks on macOS Systems

Recently, a new vulnerability with the designation CVE-2022-22582 has appeared, which affects macOS systems. The vulnerability pertains to a validation issue in the handling of symbolic links (symlinks) on the system, allowing a local user to write arbitrary files. In this long-read post, we will dive into details, including code snippets, original references, and exploit specifics for a better understanding of this vulnerability.

Context

Symbolic links, also known as symlinks, are a type of file that reference another file or directory. They have several use cases, such as providing multiple access points to files or directories and creating shortcuts for frequently accessed files. However, improper validation handling can lead to unintended consequences and create vulnerabilities.

Original References

The original report on this issue can be found in Apple's support documentation, where they provide a listing of all CVEs addressed in their recent security updates:

- Security Update 2022-003 Catalina: https://support.apple.com/en-us/HT213058
- macOS Big Sur 11.6.5: https://support.apple.com/en-us/HT213172
- macOS Monterey 12.3: https://support.apple.com/en-us/HT214090

Exploit Details

To exploit this vulnerability, an attacker would need local access to the vulnerable macOS system. The exploit involves manipulating symbolic links to bypass the original intended checks and balances, which could allow a user to overwrite arbitrary files on the system, potentially leading to the escalation of privileges or system compromise.

Here is an example code snippet that demonstrates a potential exploit strategy

import os

# Create a malicious symlink
os.symlink('/path/to/target/file', '/path/to/malicious/symlink')

# Overwrite the target file through the malicious symlink
with open('/path/to/malicious/symlink', 'w') as f:
    f.write('malicious content')

In this example, an attacker creates a malicious symlink pointing to a target file they want to overwrite. Subsequently, the attacker writes malicious content to the symlink, which in turn overwrites the target file.

Mitigation

Apple has addressed this vulnerability in their latest security updates. To protect your macOS system from the CVE-2022-22582 flaw, it is strongly recommended to apply the corresponding updates:

For macOS Monterey: Update to version 12.3

You can check and install the required updates via the System Preferences app on your macOS system.

Conclusion

CVE-2022-22582 is a vulnerability related to a validation issue in the handling of symlinks on macOS systems. A local user could exploit this vulnerability to overwrite arbitrary files, potentially leading to the escalation of privileges or system compromise. Apple has addressed this issue in their latest security updates, and users should apply the appropriate patches to safeguard their systems.

Timeline

Published on: 02/27/2023 20:15:00 UTC
Last modified on: 03/07/2023 20:21:00 UTC