Bug 1935055 (CVE-2021-28041)

Summary:	CVE-2021-28041 openssh: double-free memory corruption may lead to arbitrary code execution
Product:	[Other] Security Response	Reporter:	Marian Rehak <mrehak>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED NOTABUG	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	bdettelb, crypto-team, dbelyavs, dwalsh, jjelen, lkundrak, mattias.ellert, mbenatto, plautrba, tm, tomckay
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	openssh 8.5	Doc Type:	If docs needed, set a value
Doc Text:	A double-free memory corruption flaw was found in OpenSSH 8.2, more specifically in ssh-agent application. This flaw allows an attacker with access to the agent socket to forward an agent either to an account shared with a malicious user or to a host with an attacker holding root access. The highest threat from this vulnerability is to confidentiality, integrity, as well as system availability.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-03-08 19:01:49 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:	1935057, 1936971
Bug Blocks:	1935059

Description Marian Rehak 2021-03-04 10:25:53 UTC

A double-free memory corruption, introduced in OpenSSH 8.2, that could be reached by an attacker with access to the agent socket. Exploitable by a user forwarding an agent either to an account shared with a malicious user or to a host with an attacker holding root access.

Reference:

https://www.openssh.com/txt/release-8.5

Comment 1 Marian Rehak 2021-03-04 10:27:08 UTC

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1935057]

Comment 9 Marco Benatto 2021-03-09 17:49:31 UTC

External References:

https://www.openssh.com/txt/release-8.5

Comment 10 RaTasha Tillery-Smith 2021-03-11 13:31:38 UTC

Statement:

This issue doesn't affected any versions of OpenSSH packaged and shipped with Red Hat Enterprise Linux 6, 7 and 8. The issue was introduced in OpenSSH 8.2 while the most recent OpenSSH version available for Red Hat Enterprise Linux 8 is based on OpenSSH  8.0.

Comment 11 Marco Benatto 2021-03-12 18:32:32 UTC

Upstream fix:
https://github.com/openssh/openssh-portable/commit/e04fd6dde16de1cdc5a4d9946397ff60d96568db

The double free happens on ssh-agent