Impact

The Document script API returns directly a DocumentAuthors allowing to set any authors to the document, which in consequence can allow subsequent executions of scripts since this author is used for checking rights.
Example of such attack:

{{velocity}}
$doc.setContent('{{velocity}}$xcontext.context.authorReference{{/velocity}}')
$doc.authors.setContentAuthor('xwiki:XWiki.superadmin')
$doc.getRenderedContent()
{{/velocity}}

Patches

The problem has been patched in XWiki 14.10 and 14.4.7 by returning a safe script API.

Workarounds

There no easy workaround apart of upgrading.

References

• https://jira.xwiki.org/browse/XWIKI-20380
• 905cdd7

For more information

If you have any questions or comments about this advisory:

• Open an issue in Jira
• Email us at security ML