Certain Red Hat Enterprise Linux (RHEL) 4 and 5 packages for OpenSSH, as signed in August 2008 using a legitimate Red Hat GPG key, contain an externally introduced modification (Trojan Horse) that allows the package authors to have an unknown impact. NOTE: since the malicious packages were not distributed from any official Red Hat sources, the scope of this issue is restricted to users who may have obtained these packages through unofficial distribution points. As of 20080827, no unofficial distributions of this software are known.

From Red Hat Security Advisory 2008:0855 :

Updated openssh packages are now available for Red Hat Enterprise Linux 4, Red Hat Enterprise Linux 5, and Red Hat Enterprise Linux 4.5 Extended Update Support.

This update has been rated as having critical security impact by the Red Hat Security Response Team.

OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation.

Last week Red Hat detected an intrusion on certain of its computer systems and took immediate action. While the investigation into the intrusion is on-going, our initial focus was to review and test the distribution channel we use with our customers, Red Hat Network (RHN) and its associated security measures. Based on these efforts, we remain highly confident that our systems and processes prevented the intrusion from compromising RHN or the content distributed via RHN and accordingly believe that customers who keep their systems updated using Red Hat Network are not at risk. We are issuing this alert primarily for those who may obtain Red Hat binary packages via channels other than those of official Red Hat subscribers.

In connection with the incident, the intruder was able to sign a small number of OpenSSH packages relating only to Red Hat Enterprise Linux 4 (i386 and x86_64 architectures only) and Red Hat Enterprise Linux 5 (x86_64 architecture only). As a precautionary measure, we are releasing an updated version of these packages, and have published a list of the tampered packages and how to detect them at http://www.redhat.com/security/data/openssh-blacklist.html

To reiterate, our processes and efforts to date indicate that packages obtained by Red Hat Enterprise Linux subscribers via Red Hat Network are not at risk.

These packages also fix a low severity flaw in the way ssh handles X11 cookies when creating X11 forwarding connections. When ssh was unable to create untrusted cookie, ssh used a trusted cookie instead, possibly allowing the administrative user of a untrusted remote server, or untrusted application run on the remote server, to gain unintended access to a users local X server. (CVE-2007-4752)

Updated openssh packages are now available for Red Hat Enterprise Linux 4, Red Hat Enterprise Linux 5, and Red Hat Enterprise Linux 4.5 Extended Update Support.

This update has been rated as having critical security impact by the Red Hat Security Response Team.

OpenSSH is OpenBSD's SSH (Secure SHell) protocol implementation.

Last week Red Hat detected an intrusion on certain of its computer systems and took immediate action. While the investigation into the intrusion is on-going, our initial focus was to review and test the distribution channel we use with our customers, Red Hat Network (RHN) and its associated security measures. Based on these efforts, we remain highly confident that our systems and processes prevented the intrusion from compromising RHN or the content distributed via RHN and accordingly believe that customers who keep their systems updated using Red Hat Network are not at risk. We are issuing this alert primarily for those who may obtain Red Hat binary packages via channels other than those of official Red Hat subscribers.

In connection with the incident, the intruder was able to sign a small number of OpenSSH packages relating only to Red Hat Enterprise Linux 4 (i386 and x86_64 architectures only) and Red Hat Enterprise Linux 5 (x86_64 architecture only). As a precautionary measure, we are releasing an updated version of these packages, and have published a list of the tampered packages and how to detect them at http://www.redhat.com/security/data/openssh-blacklist.html

To reiterate, our processes and efforts to date indicate that packages obtained by Red Hat Enterprise Linux subscribers via Red Hat Network are not at risk.

These packages also fix a low severity flaw in the way ssh handles X11 cookies when creating X11 forwarding connections. When ssh was unable to create untrusted cookie, ssh used a trusted cookie instead, possibly allowing the administrative user of a untrusted remote server, or untrusted application run on the remote server, to gain unintended access to a users local X server. (CVE-2007-4752)

The remote host contains a compromised version of an OpenSSH-related package installed. 

Even though this package has been signed with the Red Hat public key, this package is considered malicious, and the remote host should be reinstalled.

ID	Name	Product	Family	Severity
67742	Oracle Linux 4 / 5 : openssh (ELSA-2008-0855)	Nessus	Oracle Linux Local Security Checks	high
43708	CentOS 4 / 5 : openssh (CESA-2008:0855)	Nessus	CentOS Local Security Checks	high
34034	RHEL 4 / 5 : openssh (RHSA-2008:0855)	Nessus	Red Hat Local Security Checks	high
34030	Remote host has a compromised Red Hat OpenSSH package installed	Nessus	Red Hat Local Security Checks	critical

Detections

Analytics

CVE-2008-3844

high

Tenable Plugins

high

high

high

critical