A security flaw was found in the way Dovecot, an IMAP and POP3 email server, performed remote server identity verification (x509 certificate's Common Name field was not checked to match provided remote server host name), when Dovecot was configured to proxy IMAP and POP3 connections to remote hosts and TLS/SSL protocols were requested (ssl=yes or starttls=yes) in the configuration to secure these connections to the destination server. A remote attacker could use this flaw to conduct man-in-the-middle (MITM) attacks via specially-crafted x509v3 certificate.
Relevant upstream patch:
This issue did NOT affect the versions of the dovecot package, as shipped with Red Hat Enterprise Linux 4 and 5.
This issue affects the versions of the dovecot package, as shipped with Red Hat Enterprise Linux 6.
This issue affects the versions of the dovecot package, as shipped with Fedora release of 14, 15, and 16. Please schedule an update.
Created dovecot tracking bugs for this issue
Affects: fedora-all [bug 754981]
This issue was assigned the name CVE-2011-4318:
(In reply to comment #0)
> Relevant upstream patch:
>  http://hg.dovecot.org/dovecot-2.0/rev/5e9eaf63a6b1
Follow-up patch improving backwards compatibility with older versions. Name check is only done when proxy destination is identified using hostname and not when its IP address is used in the configuration:
Dovecot versions 1.x do not allow using hostnames a proxy destinations, and 2.1 does not include this backwards compatibility workaround. For further details, see Timo Sirainen's mail:
This issue has been addressed in following products:
Red Hat Enterprise Linux 6
Via RHSA-2013:0520 https://rhn.redhat.com/errata/RHSA-2013-0520.html