RHSA-2009:0205 - Security Advisory

Topic

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.

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.

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

Affected Products

• Red Hat Enterprise Linux Server 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386

Fixes

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

CVEs

• CVE-2008-4870
• CVE-2008-4577

References

• http://www.redhat.com/security/updates/classification/#low