OpenSSH blacklist script

22nd August 2008

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 get 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) signed. 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.

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.

We have provided a shell script which lists the affected packages and can verify that none of them are installed on a system:

The script has a detached GPG signature from the Red Hat Security Response Team (key) so you can verify its integrity:

This script can be executed either as a non-root user or as root. To execute the script after downloading it and saving it to your system, run the command:

   bash ./openssh-blacklist-1.0.sh

If the script output includes any lines beginning with "ALERT" then a tampered package has been installed on the system. Otherwise, if no tampered packages were found, the script should produce only a single line of output beginning with the word "PASS", as shown below:

   bash ./openssh-blacklist-1.0.sh
   PASS: no suspect packages were found on this system

The script can also check a set of packages by passing it a list of source or binary RPM filenames. In this mode, a "PASS" or "ALERT" line will be printed for each filename passed; for example:

   bash ./openssh-blacklist-1.0.sh openssh-4.3p2-16.el5.i386.rpm
   PASS: signature of package "openssh-4.3p2-16.el5.i386.rpm" not on blacklist

Red Hat customers who discover any tampered packages, need help with running this script, or have any questions should log into the Red Hat support website and file a support ticket, call their local support center, or contact their Technical Account Manager.