Bug 1418710 (CVE-2017-2616)

Summary: CVE-2017-2616 util-linux: Sending SIGKILL to other processes with root privileges via su
Product: [Other] Security Response Reporter: Adam Mariš <amaris>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dkholia, kdudka, kent, kzak, security-response-team, slawomir, tmraz
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: util-linux 2.32.1 Doc Type: If docs needed, set a value
Doc Text:
A race condition was found in the way su handled the management of child processes. A local authenticated attacker could use this flaw to kill other processes with root privileges under specific conditions.
 Story Points: ---
Clone Of: Environment:
Last Closed: 2017-04-12 20:12:26 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: 1419474, 1419475, 1420262, 1425713, 1425714    
Bug Blocks: 1386080, 1418721    

Description Adam Mariš 2017-02-02 14:53:58 UTC 
If su is compiled with PAM support, it is possible for any local user to send SIGKILL to other processes with root privileges. To exploit this, the user must be able to perform su with a successful login. This does NOT have to be the root user, even using su with the same id is enough, e.g. "su $(whoami)". SIGKILL can only be sent to processes which were executed after the su process. It is not possible to send SIGKILL to processes which were already running.

Upstream patch in util-linux:

https://github.com/karelzak/util-linux/commit/dffab154d29a288aa171ff50263ecc8f2e14a891
Comment 14 Dhiru Kholia 2017-02-09 07:52:21 UTC 
Acknowledgments:

Name: Tobias Stöckmann
Comment 15 Dhiru Kholia 2017-02-22 08:22:34 UTC 
Created shadow-utils tracking bugs for this issue:

Affects: fedora-all [bug 1425714]
Comment 16 Dhiru Kholia 2017-02-22 08:22:42 UTC 
Created util-linux tracking bugs for this issue:

Affects: fedora-all [bug 1425713]
Comment 17 errata-xmlrpc 2017-03-21 10:08:47 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2017:0654 https://rhn.redhat.com/errata/RHSA-2017-0654.html
Comment 18 errata-xmlrpc 2017-04-12 12:33:38 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:0907 https://access.redhat.com/errata/RHSA-2017:0907