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mark :: blog
Red Hat Enterprise Linux 5.5 was released at the end of March 2010,
just under 7 months since the release of 5.4 in September 2009. So
let's use this opportunity to take a quick look back over the
vulnerabilities and security updates we've made in that time,
specifically for Red Hat Enterprise Linux 5 Server.
Errata count
The chart below illustrates the total number of security updates issued for Red
Hat Enterprise Linux 5 Server if you had installed 5.4, up to and including the
5.5 release, broken down by severity. I've split it into two columns, one for
the packages you'd get if you did a default install, and the other if you
installed every single package (which is unlikely as it would involve a bit of
manual effort to select every one). For a given installation, the number of
package updates and vulnerabilities that affected you will depend on exactly what you
have installed or removed.
So for a default install, from release of 5.4 up to and including
5.5, we shipped 52 advisories to address 140 vulnerabilities. 5
advisories were rated critical, 14 were important, and the remaining
33 were moderate and low.
Or, for all packages, from release of 5.4 to and including 5.5, we
shipped 75 advisories to address 187 vulnerabilities. 6 advisories
were rated critical, 18 were important, and the remaining 51 were
moderate and low.
Critical vulnerabilities
The 6 critical advisories were for 3 different packages. Given the
nature of the flaws, ExecShield protections in RHEL5 should make
exploiting the memory flaws harder.
- Four updates to Firefox (September 2009, October 2009, December 2009, February 2010)
where a malicious web site could potentially run arbitrary code as the user
running Firefox.
- An update to kdelibs
(November 2009),
where a malicious web site could potentially run arbitrary code as the
user running the Konqueror browser. kdelibs is not a default
installation package.
- An update to krb5, the Kerberos network authentication system
(January 2010),
where a remote KDC client could cause a crash or run arbitrary code as
root. This issue only affected users that have configured and enabled
krb5.
Updates to correct 24 out of the 25 critical vulnerabilities were
available via Red Hat Network either the same day, or up to one
calendar day after the issues were public. The update to fix Konqueror took
us 4 calendar days.
Overall, for Red Hat Enterprise Linux 5 since release to date, 98%
of critical vulnerabilities have had an update available to address
them available from the Red Hat Network either the same day or the
next calendar day after the issue was public.
Other significant vulnerabilities
Red Hat Enterprise Linux since 5.2 contained backported patches
from the upstream Linux kernel to add the ability to restrict
unprivileged mapping of low memory, designed to mitigate NULL pointer
dereference flaws. In the last risk report we mentioned it was found
that this protection was not sufficient, as a system with SELinux
enabled was more permissive in allowing local users in the
unconfined_t domain to map low memory areas even if the mmap_min_addr
restriction is enabled. This is
CVE-2009-2695
and was addressed in a kernel update in November 2009.
Previous updates
To compare these statistics with previous update releases we need
to take into account that the time between each update is different.
So looking at a default installation and calculating the number of
advisories per month gives the results illustrated by the following
chart:
This data is interesting to get a feel for the risk of running
Enterprise Linux 5 Server, but isn't really useful for comparisons
with other versions, distributions, or operating systems -- for
example, a default install of Red Hat Enterprise Linux 4AS did not
include Firefox, but 5 Server does. You can use
our public
security measurement data and tools, and run your own custom
metrics for any given Red Hat product, package set, timescales, and
severity range of interest.
See also:
5.3 to 5.4,
5.2 to 5.3,
5.1 to 5.2, and
5.0 to 5.1
risk reports.
Created: 27 Apr 2010
Tagged as: cve, fedora, metrics, red hat, security
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