Cross-Site Request Forgery in xwiki-platform

Impact

It's possible to know if a user has or not an account in a wiki related to an email address, and which username(s) is actually tied to that email by forging a request to the Forgot username page. Note that since this page does not have a CSRF check it's quite easy to perform a lot of those requests.

Patches

This issue has been patched in XWiki 12.10.5 and 13.2RC1. Two different patches are provided: - a first one to fix the CSRF problem - a more complex one that now relies on sending an email for the Forgot username process.

Workarounds

It's possible to fix the problem without uprading by editing the ForgotUsername page in version below 13.x, to use the following code: https://github.com/xwiki/xwiki-platform/blob/69548c0320cbd772540cf4668743e69f879812cf/xwiki-platform-core/xwiki-platform-administration/xwiki-platform-administration-ui/src/main/resources/XWiki/ForgotUsername.xml#L39-L123 In version after 13.x it's also possible to edit manually the forgotusername.vm file, but it's really encouraged to upgrade the version here.

References * https://jira.xwiki.org/browse/XWIKI-18384 * https://jira.xwiki.org/browse/XWIKI-18408

For more information

If you have any questions or comments about this advisory: * Open an issue in Jira XWiki * Email us at security ML