Impact

Any user with script rights can perform arbitrary remote code execution by adding instances of XWiki.ConfigurableClass to any page. This compromises the confidentiality, integrity and availability of the whole XWiki installation.

To reproduce on a instance, as a user with script rights, edit your user profile and add an object of type XWiki.ConfigurableClass ("Custom configurable sections").
Set "Display in section" and "Display in category" to other, "Scope" to Wiki and all spaces and "Heading" to:

#set($codeToExecute = 'Test') #set($codeToExecuteResult = '{{async}}{{groovy}}services.logging.getLogger("attacker").error("Attack from Heading succeeded!"){{/groovy}}{{/async}}')

Save the page and view it, then add ?sheet=XWiki.AdminSheet&viewer=content&section=other to the URL.
If the logs contain "attacker - Attack from Heading succeeded!", then the instance is vulnerable.

Patches

This has been patched in XWiki 15.10.9 and 16.3.0.

Workarounds

We're not aware of any workaround except upgrading.

References

• https://jira.xwiki.org/browse/XWIKI-21207
• 8493435

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