Bug 1406269 – CVE-2016-10009 openssh: loading of untrusted PKCS#11 modules in ssh-agent

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Bug 1406269 - (CVE-2016-10009) CVE-2016-10009 openssh: loading of untrusted PKCS#11 modules in ssh-agent

Summary:	CVE-2016-10009 openssh: loading of untrusted PKCS#11 modules in ssh-agent

Status:	CLOSED WONTFIX

Aliases:	CVE-2016-10009

Product:	Security Response
Classification:	Other
Component:	vulnerability (Show other bugs)
Sub Component:
Version:	unspecified
Hardware:	All Linux

Priority	medium Severity medium
Target Milestone:	---
Target Release:	---
Assigned To:	Red Hat Product Security
QA Contact:
Docs Contact:

URL:
Whiteboard:	impact=moderate,public=20161219,repor...
Keywords:	Security

Depends On:	1406296
Blocks:	1406299 1415638
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Reported:	2016-12-20 02:40 EST by Martin Prpič
Modified:	2017-11-28 17:42 EST (History)
CC List:	8 users (show)

See Also:
Fixed In Version:	openssh 7.4
Doc Type:	If docs needed, set a value
Doc Text:	It was found that ssh-agent could load PKCS#11 modules from arbitrary paths. An attacker having control of the forwarded agent-socket on the server, and the ability to write to the filesystem of the client host, could use this flaw to execute arbitrary code with the privileges of the user running ssh-agent.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2017-01-16 00:55:09 EST
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

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External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2017:2029	normal	SHIPPED_LIVE	Moderate: openssh security, bug fix, and enhancement update	2017-08-01 14:11:55 EDT

Groups: None (edit)

Description Martin Prpič 2016-12-20 02:40:41 EST

It was found that ssh-agent could load PKCS#11 modules from paths outside of a trusted whitelist. An attacker able to load a crafted PKCS#11 module across a forwarded agent channel could potentially use this flaw to execute arbitrary code on the system running the ssh-agent. Note that the attacker must have control of the forwarded agent-socket and the ability to write to the filesystem of the host running ssh-agent.

This issue was fixed by only allowing the loading of module from a trusted (and configurable) whitelist.

CVE assignment:

http://seclists.org/oss-sec/2016/q4/708

Upstream patch:

http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/ssh-agent.c.diff?r1=1.214&r2=1.215&sortby=date&f=h

Comment 1 Martin Prpič 2016-12-20 02:40:58 EST

External References:

https://www.openssh.com/txt/release-7.4

Comment 2 Andrej Nemec 2016-12-20 03:41:15 EST

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1406296]

Comment 3 Jakub Jelen 2017-01-03 09:38:10 EST

If we will want to fix it, we need to change the whitelist to something reasonable, because all of our PKCS#11 libraries are on x68_64 under /usr/lib64/
See the upstream discussion:

http://lists.mindrot.org/pipermail/openssh-unix-dev/2017-January/035631.html

Comment 4 Huzaifa S. Sidhpurwala 2017-01-16 00:55:09 EST

Statement:

In order to exploit this flaw, the attacker needs to have control of the forwarded agent-socket and the ability to write to the filesystem of the host running ssh-agent. Because of this restriction for successful exploitation, this issue has been rated as having Moderate security impact. A future update may address this flaw.

Comment 5 errata-xmlrpc 2017-08-01 14:45:28 EDT

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2017:2029 https://access.redhat.com/errata/RHSA-2017:2029

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