Postfix symlink code execution

postfix-symlink-code-execution (44460)

Medium Risk

Description:

Postfix could allow a local attacker with write permission to the mail spool directory to execute arbitrary code on the system when a root mailbox does not exist on the system, caused by an error when handling symlink files. By creating hardlink a root-owned symlink to /var/mail, an attacker could execute arbitrary code with root privileges.

*CVSS:

Base Score:	6.9
Access Vector:	Local
Access Complexity:	Medium
Authentication:	None
Confidentiality Impact:	Complete
Integrity Impact:	Complete
Availability Impact:	Complete
Temporal Score:	5.1
Exploitability:	Unproven
Remediation Level:	Official-Fix
Report Confidence:	Confirmed

Consequences:

Gain Privileges

Remedy:

Upgrade to the latest version of Postfix (2.5.4 Patchlevel 4 or later), available from the Postfix Web site. See References.

References:

• BugTraq Mailing List, Thu Aug 14 2008 - 07:03:43 CDT: Postfix local privilege escalation via hardlinked symlinks.
• Postfix Web site: Die Postfix Homepage.
• Postfix Web site: 20080814.
• SUSE Security Announcement SUSE-SA:2008:040: postfix Thu, 14 Aug 2008 14:00:00 +0000.
• ASA-2008-356: postfix security update (RHSA-2008-0839)
• BID-30691: Postfix Local Information Disclosure and Local Privilege Escalation Vulnerabilities
• CVE-2008-2936: Postfix before 2.3.15, 2.4 before 2.4.8, 2.5 before 2.5.4, and 2.6 before 2.6-20080814, when the operating system supports hard links to symlinks, allows local users to append e-mail messages to a file to which a root-owned symlink points, by creating a hard link to this symlink and then sending a message. NOTE: this can be leveraged to gain privileges if there is a symlink to an init script.
• DSA-1629: postfix -- programming error
• GLSA-200808-12: Postfix: Local privilege escalation vulnerability
• MDVSA-2008:171: postfix
• RHSA-2008-0839: Moderate: postfix security update
• SA31485: Postfix Symlink Handling and Destination Ownership Security Issues
• SECTRACK ID: 1020700: Postfix Symlink Dereference Bug Lets Local Users Gain Elevated Privileges
• SUSE-SA:2008:040: postfix security problem

Platforms Affected:

• Canonical Ubuntu 6.06 LTS
• Canonical Ubuntu 7.04
• Canonical Ubuntu 7.10
• Canonical Ubuntu 8.04 LTS
• Debian Debian Linux 4.0
• Gentoo Linux
• MandrakeSoft Mandrake Linux 2007.1
• MandrakeSoft Mandrake Linux 2007.1 X86_64
• MandrakeSoft Mandrake Linux 2008.0 X86_64
• MandrakeSoft Mandrake Linux 2008.0
• MandrakeSoft Mandrake Linux 2008.1
• MandrakeSoft Mandrake Linux 2008.1 X86_64
• MandrakeSoft Mandrake Linux Corporate Server 3.0
• MandrakeSoft Mandrake Linux Corporate Server 3.0 X86_64
• MandrakeSoft Mandrake Linux Corporate Server 4.0 X86_64
• MandrakeSoft Mandrake Linux Corporate Server 4.0
• Novell Linux Desktop 9
• Novell Linux POS 9
• Novell Open Enterprise Server
• Novell OpenSUSE 10.2
• Novell OpenSUSE 10.3
• Novell OpenSUSE 11.0
• Novell SUSE Linux Enterprise Desktop 10 SP1
• Novell SUSE Linux Enterprise Desktop 10 SP2
• Novell SUSE Linux Enterprise Server 10 SP1
• Novell SUSE Linux Enterprise Server 10 SP2
• RedHat Enterprise Linux 3 AS
• RedHat Enterprise Linux 3 WS
• RedHat Enterprise Linux 3 ES
• RedHat Enterprise Linux 3 Desktop
• RedHat Enterprise Linux 4 AS
• RedHat Enterprise Linux 4 Desktop
• RedHat Enterprise Linux 4 ES
• RedHat Enterprise Linux 4 WS
• RedHat Enterprise Linux 4.7.z AS
• RedHat Enterprise Linux 5
• RedHat Enterprise Linux 5 Client
• RedHat Enterprise Linux 5.2.z EUS
• RedHat Red Hat Enterprise Linux 4.7.z ES
• SuSE SuSE SLES 9
• Turbolinux Turbolinux 10 Server
• Turbolinux Turbolinux 10 Server x64 Ed
• Turbolinux Turbolinux 11 Server
• Turbolinux Turbolinux 11 Server x64 Ed
• Wietse Venema Postfix 2.3.0
• Wietse Venema Postfix 2.3.1
• Wietse Venema Postfix 2.3.10
• Wietse Venema Postfix 2.3.11
• Wietse Venema Postfix 2.3.12
• Wietse Venema Postfix 2.3.13
• Wietse Venema Postfix 2.3.14
• Wietse Venema Postfix 2.3.2
• Wietse Venema Postfix 2.3.3
• Wietse Venema Postfix 2.3.4
• Wietse Venema Postfix 2.3.5
• Wietse Venema Postfix 2.3.6
• Wietse Venema Postfix 2.3.7
• Wietse Venema Postfix 2.3.8
• Wietse Venema Postfix 2.3.9
• Wietse Venema Postfix 2.4.0
• Wietse Venema Postfix 2.4.1
• Wietse Venema Postfix 2.4.2
• Wietse Venema Postfix 2.4.3
• Wietse Venema Postfix 2.4.4
• Wietse Venema Postfix 2.4.5
• Wietse Venema Postfix 2.4.6
• Wietse Venema Postfix 2.4.7
• Wietse Venema Postfix 2.5.0
• Wietse Venema Postfix 2.5.1
• Wietse Venema Postfix 2.5.2
• Wietse Venema Postfix 2.5.3
• Wietse Venema Postfix 2.6.0
• Wietse Venema Postfix

Reported:

Aug 14, 2008

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