6.4 - RHSA-2009:0205

Problem Description:

An updated dovecot package that corrects two security flaws and various bugs is now available for Red Hat Enterprise Linux 5.

This update has been rated as having low security impact by the Red Hat Security Response Team.

2. Relevant releases/architectures:

RHEL Desktop Workstation (v. 5 client) - i386, x86_64 Red Hat Enterprise Linux (v. 5 server) - i386, ia64, ppc, s390x, x86_64

3. Description:

Dovecot is an IMAP server for Linux and UNIX-like systems, primarily written with security in mind.

A flaw was found in Dovecot's ACL plug-in. The ACL plug-in treated negative access rights as positive rights, which could allow an attacker to bypass intended access restrictions. (CVE-2008-4577)

A password disclosure flaw was found with Dovecot's configuration file. If a system had the "ssl_key_password" option defined, any local user could view the SSL key password. (CVE-2008-4870)

Note: This flaw did not allow the attacker to acquire the contents of the SSL key. The password has no value without the key file which arbitrary users should not have read access to.

To better protect even this value, however, the dovecot.conf file now supports the "!include_try" directive. The ssl_key_password option should be moved from dovecot.conf to a new file owned by, and only readable and writable by, root (ie 0600). This file should be referenced from dovecot.conf by setting the "!include_try [/path/to/password/file]" option.

Additionally, this update addresses the following bugs:

* the dovecot init script -- /etc/rc.d/init.d/dovecot -- did not check if the dovecot binary or configuration files existed. It also used the wrong pid file for checking the dovecot service's status. This update includes a new init script that corrects these errors.

* the %files section of the dovecot spec file did not include "%dir %{ssldir}/private". As a consequence, the /etc/pki/private/ directory was not owned by dovecot. (Note: files inside /etc/pki/private/ were and are owned by dovecot.) With this update, the missing line has been added to the spec file, and the noted directory is now owned by dovecot.

* in some previously released versions of dovecot, the authentication process accepted (and passed along un-escaped) passwords containing characters that had special meaning to dovecot's internal protocols. This updated release prevents such passwords from being passed back, instead returning the error, "Attempted login with password having illegal chars".

Note: dovecot versions previously shipped with Red Hat Enterprise Linux 5 did not allow this behavior. This update addresses the issue above but said issue was only present in versions of dovecot not previously included with Red Hat Enterprise Linux 5.

Users of dovecot are advised to upgrade to this updated package, which addresses these vulnerabilities and resolves these issues.

4. Solution:

Before applying this update, make sure that all previously-released errata relevant to your system have been applied.

This update is available via Red Hat Network. Details on how to use the Red Hat Network to apply this update are available at http://kbase.redhat.com/faq/FAQ_58_10188

5. Bugs fixed (http://bugzilla.redhat.com/):

238016 - Wrong init script 436287 - dovecot.conf is world readable - possible password exposure 439369 - new dovecot security issues from the dovecot site 448089 - dovecot should own /etc/pki/dovecot/private directory 467436 - CVE-2008-4577 dovecot: incorrect handling of negative rights in the ACL plugin 469659 - CVE-2008-4870 dovecot: ssl_key_password disclosure due to an insecure dovecot.conf permissions