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Updated dovecot packages that fix three security issues and one bug are now available for Red Hat Enterprise Linux 6.
The Red Hat Security Response Team has rated this update as having low security impact. Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) associated with each description below.
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.
- CVE-2011-2166, CVE-2011-2167
- 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.
- 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).
- 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.
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.