RedHat: Low: dovecot security and bug fix update
Posted by Benjamin D. Thomas   
RedHat Linux An updated dovecot package that fixes several security issues 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.
                   Red Hat Security Advisory

Synopsis:          Low: dovecot security and bug fix update
Advisory ID:       RHSA-2008:0297-02
Product:           Red Hat Enterprise Linux
Advisory URL:
Issue date:        2008-05-20
Updated on:        2008-05-21
CVE Names:         CVE-2007-2231 CVE-2007-4211 CVE-2007-6598 

1. Summary:

An updated dovecot package that fixes several security issues 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 discovered in the way Dovecot handled the "mail_extra_groups"
option. An authenticated attacker with local shell access could leverage
this flaw to read, modify, or delete other users mail that is stored on
the mail server. (CVE-2008-1199)

This issue did not affect the default Red Hat Enterprise Linux 5 Dovecot
configuration. This update adds two new configuration options --
"mail_privileged_group" and "mail_access_groups" -- to minimize the usage
of additional privileges.

A directory traversal flaw was discovered in Dovecot's zlib plug-in. An
authenticated user could use this flaw to view other compressed mailboxes
with the permissions of the Dovecot process. (CVE-2007-2231)

A flaw was found in the Dovecot ACL plug-in. User with only insert
permissions for a mailbox could use the "COPY" and "APPEND" commands to set
additional message flags. (CVE-2007-4211)

A flaw was found in a way Dovecot cached LDAP query results in certain
configurations. This could possibly allow authenticated users to log in as
a different user who has the same password. (CVE-2007-6598)

As well, this updated package fixes the following bugs:

* configuring "userdb" and "passdb" to use LDAP caused Dovecot to hang. A
segmentation fault may have occurred. In this updated package, using an
LDAP backend for "userdb" and "passdb" no longer causes Dovecot to hang.

* the Dovecot "login_process_size" limit was configured for 32-bit systems.
On 64-bit systems, when Dovecot was configured to use either IMAP or POP3,
the log in processes crashed with out-of-memory errors. Errors such as the
following were logged:

pop3-login: pop3-login: error while loading shared libraries: failed to map segment from shared object: Cannot allocate

In this updated package, the "login_process_size" limit is correctly
configured on 64-bit systems, which resolves this issue.

Note: this updated package upgrades dovecot to version 1.0.7. For
further details, refer to the Dovecot changelog:

Users of dovecot are advised to upgrade to this updated package, which
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

5. Bugs fixed (

238439 - CVE-2007-2231 Directory traversal in dovecot with zlib plugin
245249 - Dovecot hangs while using ldap backend.
251007 - CVE-2007-4211 Dovecot possible privilege ascalation in ACL plugin
253363 - Dovecot pop3-login/imap-login crash with OOM error
331441 - Please consider upgrading Dovecot to 1.0rc23 at least
380401 - tracker bug for 1.0.7 rebase
427575 - CVE-2007-6598: dovecot LDAP+auth cache user login mixup
436927 - CVE-2008-1199 dovecot: insecure mail_extra_groups option

6. Package List:

RHEL Desktop Workstation (v. 5 client):




Red Hat Enterprise Linux (v. 5 server):







These packages are GPG signed by Red Hat for security.  Our key and 
details on how to verify the signature are available from

7. References:

8. Contact:

The Red Hat security contact is .  More contact
details at

Copyright 2008 Red Hat, Inc.