Dear subscribers
We just published updates to all stable versions from 1.1.x onwards delivering fixes for a recently discovered file disclosure vulnerability in Roundcube Webmail.
Apparently this zero-day exploit is already being used by hackers to read Roundcube’s configuration files. It requires a valid username/password as the exploit only works with a valid session. More details will be published soon under CVE-2017-16651.
The Roundcube series 1.0.x is not affected by this vulnerability but we nevertheless back-ported the fix in order to protect from yet unknown exploits.
See the full changelog for the according version in the release notes on the Github download pages:
https://github.com/roundcube/roundcubemail/releases/tag/1.3.3 https://github.com/roundcube/roundcubemail/releases/tag/1.2.7 https://github.com/roundcube/roundcubemail/releases/tag/1.1.10 https://github.com/roundcube/roundcubemail/releases/tag/1.0.12
We strongly recommend to update all productive installations of Roundcube with either one of these versions.
In order to check whether your Roundcube installation has been compromised check the access logs for requests like
?_task=settings&_action=upload-display&_from=timezone
As mentioned above, the file disclosure only works for authenticated users and by finding such requests in the logs you should also be able to identify the account used for this unauthorized access. For mitigation we recommend to change the all credentials to external services like database or LDAP address books and preferably also the 'des_key' option in your config.
Kind regards Alec & Thomas