Bug 1406286 (CVE-2016-10011)

Summary:	CVE-2016-10011 openssh: Leak of host private key material to privilege-separated child process via realloc()
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	jjelen, mattias.ellert, mgrepl, plautrba, sardella, slawomir, tmraz, yozone
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	openssh 7.4	Doc Type:	If docs needed, set a value
Doc Text:	It was found that the host private key material could possibly leak to the privilege-separated child processes via re-allocated memory. An attacker able to compromise the privilege-separated process could therefore obtain the leaked key information.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-01-16 06:11:30 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:	1406296, 1794511
Bug Blocks:	1406299, 1415638

Description Andrej Nemec 2016-12-20 08:25:06 UTC

It was found that there is a theoretical leak of host private key material to privilege-separated child processes via realloc() when reading keys. No such leak was observed in practice for normal-sized keys, nor does a leak to the child processes directly expose key material to unprivileged users.

CVE assignment:

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

External References:

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

Comment 1 Andrej Nemec 2016-12-20 08:38:45 UTC

Upstream patch:

http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/authfile.c.diff?r1=1.121&r2=1.122

Comment 2 Andrej Nemec 2016-12-20 08:41:29 UTC

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1406296]

Comment 3 Huzaifa S. Sidhpurwala 2017-01-16 06:11:30 UTC

Statement:

It seems that this flaw is not practically exploitable, the leak of host private key material to the privilege-separated child processes is theoretical. No such leak was observed in practice for normal-sized keys, nor does a leak to the child processes directly expose key material to unprivileged users. Because of the this restriction for successful exploitation, this issue has been rated as having Low security impact. A future update may address this flaw.

Comment 4 errata-xmlrpc 2017-08-01 18:45:35 UTC

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