Bug 1252852 (CVE-2015-6564)

Summary:	CVE-2015-6564 openssh: Use-after-free bug related to PAM support
Product:	[Other] Security Response	Reporter:	Adam Mariš <amaris>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED ERRATA	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	carnil, gnaik, jaeshin, jjelen, mattias.ellert, mgrepl, mike.r.karras, plautrba, rhbugs, santony, sardella, security-response-team, slawomir, szidek, tmraz
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	openssh 7.0	Doc Type:	Bug Fix
Doc Text:	A use-after-free flaw was found in OpenSSH. An attacker able to fully compromise a non-privileged pre-authentication process using a different flaw could possibly cause sshd to crash or execute arbitrary code with root privileges.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-05-11 06:44:26 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:	1252853, 1265807, 1281468
Bug Blocks:	1210268, 1252864, 1278736

Description Adam Mariš 2015-08-12 11:25:45 UTC

Use-after-free bug was found in openssh package. The vulnerability is exploitable by attackers who could compromise the pre-authentication process for remote code execution.

Upstream patch:

https://anongit.mindrot.org/openssh.git/commit/?id=5e75f5198769056089fb06c4d738ab0e5abc66f7

CVE request:

http://seclists.org/oss-sec/2015/q3/319

External References:

http://www.openssh.com/txt/release-7.0

Comment 1 Adam Mariš 2015-08-12 11:26:37 UTC

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1252853]

Comment 2 Fedora Update System 2015-08-18 05:19:29 UTC

openssh-7.0p1-1.fc23 has been pushed to the Fedora 23 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 3 Fedora Update System 2015-08-19 08:15:49 UTC

openssh-6.9p1-5.fc22 has been pushed to the Fedora 22 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 4 Slawomir Czarko 2015-08-25 08:08:05 UTC

Is this CVE-2015-6564? The patches look the same.

https://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2015-6564

Comment 5 Adam Mariš 2015-08-25 12:41:49 UTC

CVE assignment:

http://seclists.org/oss-sec/2015/q3/419

Comment 6 Fedora Update System 2015-08-27 23:48:57 UTC

openssh-6.6.1p1-16.fc21 has been pushed to the Fedora 21 stable repository. If problems still persist, please make note of it in this bug report.

Comment 9 Tomas Hoger 2015-09-23 19:49:04 UTC

Further details of this issue can be found in the advisory form the original reporter that was posted to the full-disclosure mailing list:

http://seclists.org/fulldisclosure/2015/Aug/54

The advisory indicates that the use-after-free can only be triggered if attacker is able to fully compromise non-privileged pre-authentication process using some different flaw.  Reporter also indicates that they were unable to leverage this issue for any practical attack.

Comment 14 errata-xmlrpc 2015-11-19 08:05:35 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2015:2088 https://rhn.redhat.com/errata/RHSA-2015-2088.html

Comment 17 errata-xmlrpc 2016-05-10 19:29:19 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 6

Via RHSA-2016:0741 https://rhn.redhat.com/errata/RHSA-2016-0741.html