I discovered (aside bug #1056767) another flaw in Zarafa that could allow a remote unauthenticated attacker to crash the zarafa-server daemon, preventing access to any other legitimate Zarafa users.

The issue affects all Zarafa versions from at least Zarafa 6.20.0 (maybe even from at least Zarafa 5.00) up to (including) Zarafa 7.1.8 final. Please note that I was not able to crash the zarafa-server daemon using official upstream Zarafa binary packages just all community builds from the source code such as shipped in Fedora. This different behaviour might be caused that upstream uses different built-time flags or other system libraries and headers.

Once the zarafa-server process crashes with a backtrace (and even all other Zarafa related daemons are still running) there is no Zarafa functionality till zarafa-server daemon is started again. The zarafa-server process provides the MAPI in SOAP service required by all other Zarafa related components as shown: http://doc.zarafa.com/trunk/AdministratorManual/en-US/html/architecture.html

Robert Scheck discovered a flaw in Zarafa that could allow a remote unauthenticated attacker to crash the zarafa-server daemon, preventing access to any other legitimate Zarafa users.

Acknowledgements:

Red Hat would like to thank Robert Scheck of ETES GmbH for reporting this issue.