Bug 1238238 – openssh: weakness of agent locking (ssh-add -x) to password guessing

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Bug 1238238 - openssh: weakness of agent locking (ssh-add -x) to password guessing

Summary:	openssh: weakness of agent locking (ssh-add -x) to password guessing

Status:	CLOSED ERRATA

Aliases:	None

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=20150701,repor...
Keywords:	Security

Depends On:	1238241 1247864 1281468
Blocks:	1252864
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Reported:	2015-07-01 08:55 EDT by Vasyl Kaigorodov
Modified:	2016-05-11 04:09 EDT (History)
CC List:	9 users (show)

See Also:
Fixed In Version:	OpenSSH 6.9
Doc Type:	Bug Fix
Doc Text:	It was found that the OpenSSH ssh-agent, a program to hold private keys used for public key authentication, was vulnerable to password guessing attacks. An attacker able to connect to the agent could use this flaw to conduct a brute-force attack to unlock keys in the ssh-agent.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2016-05-11 04:09:54 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2015:2088	normal	SHIPPED_LIVE	Moderate: openssh security, bug fix, and enhancement update	2015-11-19 03:38:51 EST

Groups: None (edit)

Description Vasyl Kaigorodov 2015-07-01 08:55:56 EDT

OpenSSH version 6.9 fix weakness of agent locking (ssh-add -x) to password guessing by implementing an increasing failure delay, storing a salted hash of the password rather than the password itself and using a timing-safe comparison function for verifying unlock attempts. This problem was reported by Ryan Castellucci.
Upstream patch: https://anongit.mindrot.org/openssh.git/commit/?h=V_6_9&id=9173d0fbe44de7ebcad8a15618e13a8b8d78902e

External References:

http://www.openssh.com/txt/release-6.9

Comment 1 Vasyl Kaigorodov 2015-07-01 08:59:26 EDT

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1238241]

Comment 2 Martin Prpič 2015-07-02 08:20:57 EDT

Per http://openwall.com/lists/oss-security/2015/07/01/10 , MITRE did not assign a CVE to this issue:

"Our current thought is that a CVE ID may not be needed because attacks against ssh-agent locking don't cross a privilege boundary. In other words, the changelog entry could be interpreted to mean addition of a new security feature related to a threat model that wasn't in the previous design goals (e.g., password guessing by malware running under the same account)."

Comment 3 Fedora Update System 2015-07-10 15:09:15 EDT

openssh-6.6.1p1-13.fc21 has been pushed to the Fedora 21 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 4 Fedora Update System 2015-07-10 15:18:17 EDT

openssh-6.9p1-1.fc22 has been pushed to the Fedora 22 stable repository.  If problems still persist, please make note of it in this bug report.

Comment 12 errata-xmlrpc 2015-11-19 03:03:45 EST

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

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