Red Hat Enterprise Linux 5 was released back in March 2007 so let's take a quick look back over the first three months of security updates to the Server distribution:
- We released updates to ten packages on the day we shipped the product. These is because we freeze packages some months before releasing the product (more information about this policy). Only one of those updates was rated critical, an update to Firefox.
- For the three months following release we shipped 31 more advisories to address 56 vulnerabilities: 3 advisories were rated critical, 8 were important, and the remaining 20 were moderate and low.
- The three critical advisories were:
- Another update to Firefox where a malicious web site could potentially run arbitrary code as the user running Firefox. Given the nature of the flaws, Execshield protections in RHEL5 should make exploiting these issues harder.
- An update to Samba where a remote attacker could cause a heap overflow. In addition to Execshield making this harder to exploit, the impact of any successful exploit would be reduced as Samba is constrained by an SELinux targeted policy (enabled by default).
- An update to the Kerberos telnet deamon. A remote attacker who can access the telnet port of a target machine could log in as root without requiring a password. None of the standard protection mechanisms help prevent exploitation of this issue, however the krb5 telnet daemon is not enabled by default in RHEL5 and the default firewall rules block remote access to the telnet port. This flaw did not affect the more common telnet daemon distributed in the telnet-server package.
- Updates to correct all of these critical issues were available via Red Hat Network on the same day as the issues were made public.
This data is interesting to get a feel for the risk of running EL5, but isn't really useful for comparisons with other versions or distributions -- for example previous versions didn't include Firefox in a default Server installation.