Headline
GHSA-j2pq-22jj-4pm5: XWiki allows remote code execution through the extension sheet
Impact
On instances where Extension Repository Application is installed, any user can execute any code requiring programming rights on the server.
In order to reproduce on an instance, as a normal user without script nor programming rights, go to your profile and add an object of type ExtensionCode.ExtensionClass. Set the description to {{async}}{{groovy}}println("Hello from Description"){{/groovy}}{{/async}} and press Save and View. If the description displays as Hello from Description without any error, then the instance is vulnerable.
Patches
This vulnerability has been fixed in XWiki 15.10.9 and 16.3.0.
Workarounds
Since Extension Repository Application is not mandatory, it can be safely disabled on instances that do not use it.
It is also possible to manually apply this patch to the page ExtensionCode.ExtensionSheet, as well as this patch to the page ExtensionCode.ExtensionAuthorsDisplayer.
References
- https://jira.xwiki.org/browse/XWIKI-21890
- https://github.com/xwiki/xwiki-platform/commit/8659f17d500522bf33595e402391592a35a162e8
For more information
If you have any questions or comments about this advisory:
- Open an issue in Jira XWiki.org
- Email us at Security Mailing List
Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.