Arbitrary file access through XML parsing in org.xwiki.commons:xwiki-commons-xml

Impact

It's possible in a script to access any file accessing to the user running XWiki application server with XML External Entity Injection through the XML script service.

For example:

{{velocity}}
#set($xml=$services.get('xml'))
#set($xxe_payload = "<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE root[<!ENTITY xxe SYSTEM 'file:///etc/passwd' >]><root><foo>&xxe;</foo></root>")
#set($doc=$xml.parse($xxe_payload))
$xml.serialize($doc)
{{/velocity}}

Patches

The problem has been patched on versions 12.10.10, 13.4.4 and 13.8RC1.

Workarounds

There's no easy workaround for fixing this vulnerability other than upgrading and being careful when giving Script rights.

References

https://jira.xwiki.org/browse/XWIKI-18946

For more information

If you have any questions or comments about this advisory:

• Open an issue in Jira XWiki
• Email us at XWiki Security mailing-list