CVE-2023-4052

The Firefox updater created a directory writable by non-privileged users. When uninstalling Firefox, any files in that directory would be recursively deleted with the permissions of the uninstalling user account. This could be combined with creation of a junction (a form of symbolic link) to allow arbitrary file deletion controlled by the non-privileged user. This bug only affects Firefox on Windows. Other operating systems are unaffected. This vulnerability affects Firefox < 116, Firefox ESR < 115.1, and Thunderbird < 115.1.

Weakness

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected Software

Potential Mitigations

• Follow the principle of least privilege when assigning access rights to entities in a software system.
• Denying access to a file can prevent an attacker from replacing that file with a link to a sensitive file. Ensure good compartmentalization in the system to provide protected areas that can be trusted.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/132.html
• https://cwe.mitre.org/data/definitions/17.html
• https://cwe.mitre.org/data/definitions/35.html
• https://cwe.mitre.org/data/definitions/76.html

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1824420
• https://www.mozilla.org/security/advisories/mfsa2023-29/
• https://www.mozilla.org/security/advisories/mfsa2023-31/
• https://www.mozilla.org/security/advisories/mfsa2023-33/