(RHSA-2013:0520) Low: dovecot security and bug fix update

Dovecot is an IMAP server, written with security primarily in mind, for
Linux and other UNIX-like systems. It also contains a small POP3 server. It
supports mail in either of maildir or mbox formats. The SQL drivers and
authentication plug-ins are provided as sub-packages.

Two flaws were found in the way some settings were enforced by the
script-login functionality of Dovecot. A remote, authenticated user could
use these flaws to bypass intended access restrictions or conduct a
directory traversal attack by leveraging login scripts. (CVE-2011-2166,
CVE-2011-2167)

A flaw was found in the way Dovecot performed remote server identity
verification, when it was configured to proxy IMAP and POP3 connections to
remote hosts using TLS/SSL protocols. A remote attacker could use this flaw
to conduct man-in-the-middle attacks using an X.509 certificate issued by
a trusted Certificate Authority (for a different name). (CVE-2011-4318)

This update also fixes the following bug:

• When a new user first accessed their IMAP inbox, Dovecot was, under some
  circumstances, unable to change the group ownership of the inbox directory
  in the user’s Maildir location to match that of the user’s mail spool
  (/var/mail/$USER). This correctly generated an “Internal error occurred”
  message. However, with a subsequent attempt to access the inbox, Dovecot
  saw that the directory already existed and proceeded with its operation,
  leaving the directory with incorrectly set permissions. This update
  corrects the underlying permissions setting error. When a new user now
  accesses their inbox for the first time, and it is not possible to set
  group ownership, Dovecot removes the created directory and generates an
  error message instead of keeping the directory with incorrect group
  ownership. (BZ#697620)

Users of dovecot are advised to upgrade to these updated packages, which
contain backported patches to correct these issues. After installing the
updated packages, the dovecot service will be restarted automatically.