CVE-2023-40028

Ghost is an open source content management system. Versions prior to 5.59.1 are subject to a vulnerability which allows authenticated users to upload files that are symlinks. This can be exploited to perform an arbitrary file read of any file on the host operating system. Site administrators can check for exploitation of this issue by looking for unknown symlinks within Ghosts content/ folder. Version 5.59.1 contains a fix for this issue. All users are advised to upgrade. There are no known workarounds for this vulnerability.

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://github.com/TryGhost/Ghost/commit/690fbf3f7302ff3f77159c0795928bdd20f41205
• https://github.com/TryGhost/Ghost/security/advisories/GHSA-9c9v-w225-v5rg