RHSA-2011:0422 - Security Advisory

Topic

Updated postfix packages that fix two security issues are now available for
Red Hat Enterprise Linux 4 and 5.

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

Postfix is a Mail Transport Agent (MTA), supporting LDAP, SMTP AUTH (SASL),
and TLS.

It was discovered that Postfix did not flush the received SMTP commands
buffer after switching to TLS encryption for an SMTP session. A
man-in-the-middle attacker could use this flaw to inject SMTP commands into
a victim's session during the plain text phase. This would lead to those
commands being processed by Postfix after TLS encryption is enabled,
possibly allowing the attacker to steal the victim's mail or authentication
credentials. (CVE-2011-0411)

It was discovered that Postfix did not properly check the permissions of
users' mailbox files. A local attacker able to create files in the mail
spool directory could use this flaw to create mailbox files for other local
users, and be able to read mail delivered to those users. (CVE-2008-2937)

Red Hat would like to thank the CERT/CC for reporting CVE-2011-0411, and
Sebastian Krahmer of the SuSE Security Team for reporting CVE-2008-2937.
The CERT/CC acknowledges Wietse Venema as the original reporter of
CVE-2011-0411.

Users of Postfix are advised to upgrade to these updated packages, which
contain backported patches to resolve these issues. After installing this
update, the postfix 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 5 x86_64
• Red Hat Enterprise Linux Server 5 ia64
• Red Hat Enterprise Linux Server 5 i386
• Red Hat Enterprise Linux Server 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 5.6 i386
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 x86_64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 ia64
• Red Hat Enterprise Linux for x86_64 - Extended Update Support 4.8 i386
• Red Hat Enterprise Linux Server - AUS 5.6 x86_64
• Red Hat Enterprise Linux Server - AUS 5.6 ia64
• Red Hat Enterprise Linux Server - AUS 5.6 i386
• Red Hat Enterprise Linux Workstation 5 x86_64
• Red Hat Enterprise Linux Workstation 5 i386
• Red Hat Enterprise Linux Workstation 4 x86_64
• Red Hat Enterprise Linux Workstation 4 ia64
• Red Hat Enterprise Linux Workstation 4 i386
• Red Hat Enterprise Linux Desktop 5 x86_64
• Red Hat Enterprise Linux Desktop 5 i386
• Red Hat Enterprise Linux Desktop 4 x86_64
• Red Hat Enterprise Linux Desktop 4 i386
• Red Hat Enterprise Linux for IBM z Systems 5 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 5.6 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 4.8 s390x
• Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 4.8 s390
• Red Hat Enterprise Linux for Power, big endian 5 ppc
• Red Hat Enterprise Linux for Power, big endian 4 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 5.6 ppc
• Red Hat Enterprise Linux for Power, big endian - Extended Update Support 4.8 ppc
• Red Hat Enterprise Linux Server from RHUI 5 x86_64
• Red Hat Enterprise Linux Server from RHUI 5 i386
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 x86_64
• Red Hat Enterprise Linux Server - Extended Update Support from RHUI 5.6 i386

Fixes

• BZ - 456347 - CVE-2008-2937 postfix improper mailbox permissions
• BZ - 674814 - CVE-2011-0411 postfix: SMTP commands injection during plaintext to TLS session switch

CVEs

• CVE-2008-2937
• CVE-2011-0411

References

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