Bug 456314 (CVE-2008-2936)

Summary: CVE-2008-2936 postfix privilege escalation flaw
Product: [Other] Security Response Reporter: Josh Bressers <bressers>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: azelinka, kreilly, redhat-bugzilla, security-response-team, twoerner
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2008-10-10 07:27:12 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 456714, 456715, 456716, 456717, 456718, 459099, 459100, 459101, 833970    
Bug Blocks:    
Attachments:
Description Flags
Proposed upstream patch
none
Updated upstream patch none

Description Josh Bressers 2008-07-22 19:16:31 UTC 
Sebastian Krahmer reported a flaw in the way postfix handle symlink files owned
by root.  If a user has write permission to the mail spool directory (this means
that the user is in the mail group on our systems, which is unlikely), and there
is no root mailbox, they can create a hard link to a root owned symlink. 
Postfix will append mail messages to an arbitrary file, which could result in
the local user gaining root privileges.

Acknowledgements:

Red Hat would like to thank Sebastian Krahmer for responsibly disclosing
this issue.
Comment 2 Josh Bressers 2008-07-22 19:19:05 UTC 
This flaw affects Red Hat Enterprise Linux 3, 4, and 5.
Comment 3 Josh Bressers 2008-07-25 18:33:33 UTC 
Created attachment 312664 [details]
Proposed upstream patch
Comment 5 Josh Bressers 2008-08-07 23:54:42 UTC 
Created attachment 313762 [details]
Updated upstream patch
Comment 6 Josh Bressers 2008-08-08 00:01:09 UTC 
Thomas,

Can you roll up some new packages for this?  I'll write up the errata tomorrow.

Thanks.
Comment 7 Josh Bressers 2008-08-08 15:14:49 UTC 
This is going to be RHSA-2008-0839.

It now needs packages.
Comment 8 Josh Bressers 2008-08-14 13:20:49 UTC 
This is now public:
http://archives.neohapsis.com/archives/postfix/2008-08/0392.html
Comment 9 Josh Bressers 2008-08-14 13:23:17 UTC 
*** Bug 459091 has been marked as a duplicate of this bug. ***
Comment 12 Tomas Hoger 2008-09-02 07:47:29 UTC 
Public PoC posted to multiple security lists:

http://marc.info/?l=bugtraq&m=122029567530728&w=4
Comment 13 Fedora Update System 2008-10-09 21:31:11 UTC 
postfix-2.5.5-1.fc8 has been pushed to the Fedora 8 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 14 Fedora Update System 2008-10-09 21:33:09 UTC 
postfix-2.5.5-1.fc9 has been pushed to the Fedora 9 stable repository.  If problems still persist, please make note of it in this bug report.
Comment 15 Red Hat Product Security 2008-10-10 07:27:12 UTC 
This issue was addressed in:

Red Hat Enterprise Linux:
  http://rhn.redhat.com/errata/RHSA-2008-0839.html

Fedora:
  https://admin.fedoraproject.org/updates/F8/FEDORA-2008-8595
  https://admin.fedoraproject.org/updates/F9/FEDORA-2008-8593