Bug 862324 (CVE-2013-4394)

Summary: CVE-2013-4394 systemd: Improper sanitization of invalid XKB layouts descriptions (privilege escalation when custom PolicyKit local authority file used)
Product: [Other] Security Response Reporter: Jan Lieskovsky <jlieskov>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED CURRENTRELEASE QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: fweimer, lpoetter, security-response-team
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2014-02-12 06:08:02 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 859931    
Bug Blocks: 859151    

Description Jan Lieskovsky 2012-10-02 15:58:23 UTC 
A possibility of unauthorized Xorg X11 Server configuration file modification / injection was found in the way SetX11Keyboard() method of systemd, a system and service manager, performed sanitization of provided X Keyboard Extension (XKB) layouts description (special and control characters were not filtered out from the layout description properly). When the host in question used PolicyKit Local Authority (PKLA) file mechanism to grant group of users the privilege to change XKB settings (instead of default PolicyKit check) and particular local attacker was member of that group, they could use this flaw to inject arbitrary values into the Xorg X11 Server configuration file, possibly leading to escalation of their privileges.

Issue found by Florian Weimer, Red Hat Product Security Team
Comment 9 Vincent Danen 2013-10-01 22:49:28 UTC 
This was assigned CVE-2013-4394:

http://www.openwall.com/lists/oss-security/2013/10/01/9
Comment 10 Vincent Danen 2013-10-01 22:50:25 UTC 
Acknowledgements:

This issue was discovered by Florian Weimer of the Red Hat Product Security Team.
Comment 11 Huzaifa S. Sidhpurwala 2013-10-04 09:50:00 UTC 
Upstream patch:
http://cgit.freedesktop.org/systemd/systemd/commit/?id=8d789b905dba8aebd30238520b6ad52fb866af95
Comment 12 Huzaifa S. Sidhpurwala 2013-10-04 09:50:57 UTC 
This issue has been addressed in the version of systemd as shipped with Fedora 18 and 19. (Current versions are not affected)