GLSA 200611-06: OpenSSH: Multiple Denial of Service vulnerabilities

http://security.gentoo.org/

Severity:	normal
Title:	OpenSSH: Multiple Denial of Service vulnerabilities
Date:	11/13/2006
Bugs:	#149502
ID:	200611-06

Synopsis

Several Denial of Service vulnerabilities have been identified in OpenSSH.

Background

OpenSSH is a complete SSH protocol version 1.3, 1.5 and 2.0 implementation and includes sftp client and server support.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
net-misc/openssh	< 4.4_p1-r5	>= 4.4_p1-r5	All supported architectures

Description

Tavis Ormandy of the Google Security Team has discovered a pre-authentication vulnerability, causing sshd to spin until the login grace time has been expired. Mark Dowd found an unsafe signal handler that was vulnerable to a race condition. It has also been discovered that when GSSAPI authentication is enabled, GSSAPI will in certain cases incorrectly abort.

Impact

The pre-authentication and signal handler vulnerabilities can cause a Denial of Service in OpenSSH. The vulnerability in the GSSAPI authentication abort could be used to determine the validity of usernames on some platforms.

Workaround

There is no known workaround at this time.

Resolution

All OpenSSH users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=net-misc/openssh-4.4_p1-r5"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200611-06.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.