FreeBSD : OpenSSH -- Memory corruption in sshd (5709d244-4873-11e3-8a46-000d601460a4)

high Nessus Plugin ID 70795

Synopsis

The remote FreeBSD host is missing one or more security-related updates.

Description

The OpenSSH development team reports :

A memory corruption vulnerability exists in the post- authentication sshd process when an AES-GCM cipher ([email protected] or [email protected]) is selected during kex exchange.

If exploited, this vulnerability might permit code execution with the privileges of the authenticated user and may therefore allow bypassing restricted shell/command configurations.

Either upgrade to 6.4 or disable AES-GCM in the server configuration.
The following sshd_config option will disable AES-GCM while leaving other ciphers active :

Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,blowfish-cbc,cast 128-cbc,aes192-cbc,aes256-cbc

Solution

Update the affected packages.

See Also

http://www.openssh.com/txt/gcmrekey.adv

http://www.nessus.org/u?3f7522ce

Plugin Details

Severity: High

ID: 70795

File Name: freebsd_pkg_5709d244487311e38a46000d601460a4.nasl

Version: 1.6

Type: local

Published: 11/9/2013

Updated: 1/6/2021

Supported Sensors: Nessus

Vulnerability Information

CPE: p-cpe:/a:freebsd:freebsd:openssh-portable, p-cpe:/a:freebsd:freebsd:openssh-portable-base, cpe:/o:freebsd:freebsd

Required KB Items: Host/local_checks_enabled, Host/FreeBSD/release, Host/FreeBSD/pkg_info

Patch Publication Date: 11/8/2013

Vulnerability Publication Date: 11/7/2013