RHEL 5 : openssh (RHSA-2009:1287)

critical Nessus Plugin ID 40837

Synopsis

The remote Red Hat host is missing a security update.

Description

The remote Redhat Enterprise Linux 5 host has packages installed that are affected by a vulnerability as referenced in the RHSA-2009:1287 advisory.

OpenSSH is OpenBSD's SSH (Secure Shell) protocol implementation. These packages include the core files necessary for both the OpenSSH client and server.

A flaw was found in the SSH protocol. An attacker able to perform a man-in-the-middle attack may be able to obtain a portion of plain text from an arbitrary ciphertext block when a CBC mode cipher was used to encrypt SSH communication. This update helps mitigate this attack: OpenSSH clients and servers now prefer CTR mode ciphers to CBC mode, and the OpenSSH server now reads SSH packets up to their full possible length when corruption is detected, rather than reporting errors early, reducing the possibility of successful plain text recovery. (CVE-2008-5161)

This update also fixes the following bug:

* the ssh client hung when trying to close a session in which a background process still held tty file descriptors open. With this update, this so-called hang on exit error no longer occurs and the ssh client closes the session immediately. (BZ#454812)

In addition, this update adds the following enhancements:

* the SFTP server can now chroot users to various directories, including a user's home directory, after log in. A new configuration option -- ChrootDirectory -- has been added to /etc/ssh/sshd_config for setting this up (the default is not to chroot users). Details regarding configuring this new option are in the sshd_config(5) manual page. (BZ#440240)

* the executables which are part of the OpenSSH FIPS module which is being validated will check their integrity and report their FIPS mode status to the system log or to the terminal. (BZ#467268, BZ#492363)

All OpenSSH users are advised to upgrade to these updated packages, which contain backported patches to resolve these issues and add these enhancements. After installing this update, the OpenSSH server daemon (sshd) will be restarted automatically.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

Plugin Details

Severity: Critical

ID: 40837

File Name: redhat-RHSA-2009-1287.nasl

Version: 1.27

Type: local

Agent: unix

Family: Red Hat Local Security Checks

Published: 9/2/2009

Updated: 11/4/2024

Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3.4

Vendor

Vendor Severity: Low

CVSS v2

Risk Factor: Low

Base Score: 2.6

Temporal Score: 1.9

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N

CVSS Score Source: CVE-2008-5161

CVSS v3

Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

CPE: p-cpe:/a:redhat:enterprise_linux:openssh-askpass, cpe:/o:redhat:enterprise_linux:5, p-cpe:/a:redhat:enterprise_linux:openssh, p-cpe:/a:redhat:enterprise_linux:openssh-server, p-cpe:/a:redhat:enterprise_linux:openssh-clients

Required KB Items: Host/local_checks_enabled, Host/RedHat/release, Host/RedHat/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 9/2/2009

Vulnerability Publication Date: 11/19/2008

Reference Information

CVE: CVE-2008-5161

BID: 32319

RHSA: 2009:1287

Detections

Analytics