GLSA 201601-01: OpenSSH: Multiple vulnerabilities

http://security.gentoo.org/

Severity:	normal
Title:	OpenSSH: Multiple vulnerabilities
Date:	01/16/2016
Bugs:	#571892
ID:	201601-01

Synopsis

Multiple vulnerabilities have been found in OpenSSH, allowing attackers to leak client memory to a server, including private keys.

Background

OpenSSH is a complete SSH protocol implementation that includes SFTP client and server support.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
net-misc/openssh	< 7.1_p2	>= 7.1_p2	All supported architectures

Description

Qualys have reported two issues in the “roaming” code included in the OpenSSH client, which provides undocumented, experimental support for resuming SSH connections. An OpenSSH client could be tricked into leaking parts of its memory to a malicious server. Furthermore, a buffer overflow can be exploited by a malicious server, but its exploitation requires non-default options and is mitigated due to another bug.

Impact

A remote attacker could entice a user to connect to a specially crafted OpenSSH server, possibly resulting in the disclosure of the user’s private keys. Users with private keys that are not protected by a passphrase are advised to generate new keys if they have connected to an SSH server they don’t fully trust.

Note that no special configuration is required to be vulnerable as the roaming feature is enabled by default on the client.

Workaround

The issues can be worked around by disabling the roaming code. To do so, add “UseRoaming no” to the SSH client configuration, or specify “-o ‘UseRoaming no’” on the command line.

Resolution

All OpenSSH users should upgrade to the latest version:

      # emerge --sync
      # emerge --ask --oneshot --verbose ">=net-misc/openssh-7.1_p2"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-201601-01.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.