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: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED NOTABUG QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: 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:
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