Bug 1364935 – CVE-2016-6515 openssh: Denial of service via very long passwords

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Bug 1364935 - (CVE-2016-6515) CVE-2016-6515 openssh: Denial of service via very long passwords

Summary:	CVE-2016-6515 openssh: Denial of service via very long passwords

Status:	NEW

Aliases:	CVE-2016-6515

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=20160721,repor...
Keywords:	Reopened, Security

Depends On:	1364936 1446514
Blocks:	1364938 1415638
	Show dependency tree / graph

Reported:	2016-08-08 05:08 EDT by Andrej Nemec
Modified:	2018-03-29 18:01 EDT (History)
CC List:	6 users (show)

See Also:
Fixed In Version:	openssh 7.3
Doc Type:	If docs needed, set a value
Doc Text:	It was found that OpenSSH did not limit password lengths for password authentication. A remote unauthenticated attacker could use this flaw to temporarily trigger high CPU consumption in sshd by sending long passwords.
Story Points:	---
Clone Of:
Environment:
Last Closed:	2016-08-08 05:13:43 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-2017:2029	normal	SHIPPED_LIVE	Moderate: openssh security, bug fix, and enhancement update	2017-08-01 14:11:55 EDT

Groups: None (edit)

Description Andrej Nemec 2016-08-08 05:08:10 EDT

A denial of service vulnerability was found in openssh. The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.

References:

http://seclists.org/oss-sec/2016/q3/215

Upstream fix:

https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97

Comment 1 Andrej Nemec 2016-08-08 05:08:35 EDT

Created openssh tracking bugs for this issue:

Affects: fedora-all [bug 1364936]

Comment 5 Dhiru Kholia 2017-04-26 03:37:31 EDT

Statement:

This issue in OpenSSH is mitigated by the usage of SELinux in Red Hat Enterprise Linux 6 and Red Hat Enterprise Linux 7.

Comment 7 errata-xmlrpc 2017-08-01 14:45:18 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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