RHSA-2011:0600 - Security Advisory

Topic

Updated dovecot packages that fix two security issues and add one
enhancement are now available for Red Hat Enterprise Linux 6.

The Red Hat Security Response Team has rated this update as having moderate
security impact. Common Vulnerability Scoring System (CVSS) base scores,
which give detailed severity ratings, are available for each vulnerability
from the CVE links in the References section.

Description

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

A flaw was found in the way Dovecot handled SIGCHLD signals. If a large
amount of IMAP or POP3 session disconnects caused the Dovecot master
process to receive these signals rapidly, it could cause the master process
to crash. (CVE-2010-3780)

A flaw was found in the way Dovecot processed multiple Access Control Lists
(ACL) defined for a mailbox. In some cases, Dovecot could fail to apply the
more specific ACL entry, possibly resulting in more access being granted to
the user than intended. (CVE-2010-3707)

This update also adds the following enhancement:

• This erratum upgrades Dovecot to upstream version 2.0.9, providing

multiple fixes for the "dsync" utility and improving overall performance.
Refer to the "/usr/share/doc/dovecot-2.0.9/ChangeLog" file after installing
this update for further information about the changes. (BZ#637056)

Users of dovecot are advised to upgrade to these updated packages, which
resolve these issues and add this enhancement. After installing the updated
packages, the dovecot service will be restarted automatically.

Solution

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

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 6 x86_64
• Red Hat Enterprise Linux Server 6 i386
• Red Hat Enterprise Linux Workstation 6 i386
• Red Hat Enterprise Linux for IBM z Systems 6 s390x
• Red Hat Enterprise Linux for Power, big endian 6 ppc64
• Red Hat Enterprise Linux Server from RHUI 6 x86_64
• Red Hat Enterprise Linux Server from RHUI 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support 6 i386
• Red Hat Enterprise Linux Workstation 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 6 s390x
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 x86_64
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension 6 i386
• Red Hat Enterprise Linux Server - Extended Life Cycle Support Extension (for IBM z Systems) 6 s390x

Fixes

• BZ - 637056 - rebase dovecot to 2.0 final
• BZ - 640410 - CVE-2010-3707 Dovecot: Failed to properly update ACL cache, when multiple rules defined rights for one subject
• BZ - 641276 - CVE-2010-3780 Dovecot: Busy master process, receiving a lot of SIGCHLD signals rapidly while logging, could die

CVEs

• CVE-2010-3780
• CVE-2010-3707

References

• https://access.redhat.com/security/updates/classification/#moderate