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Debian Server restored after Compromise

The Debian Project                                http://www.debian.org/
Debian Server restored after Compromise          debian-admin@debian.org
July 13th, 2006                 http://www.debian.org/News/2005/20060713

Debian Server restored after Compromise

One core Debian server has been reinstalled after a compromise and
services have been restored.  On July 12th the host gluck.debian.org
has been compromised using a local root vulnerability in the Linux
kernel.  The intruder had access to the server using a compromised
developer account.

The services affected and temporarily taken down are: cvs, ddtp,
lintian, people, popcon, planet, ports, release.


At least one developer account has been compromised a while ago and
has been used by an attacker to gain access to the Debian server.  A
recently discovered local root vulnerability in the Linux kernel has
then been used to gain root access to the machine.

At 02:43 UTC on July 12th suspicious mails were received and alarmed
the Debian admins.   The following investigation turned out that a
developer account was compromised and that a local kernel
vulnerability has been exploited to gain root access.

At 04:30 UTC on July 12th gluck has been taken offline and booted off
trusted media.  Other Debian servers have been locked down for further
investigation whether they were compromised as well.  They will be
upgraded to a corrected kernel before they will be unlocked.

Due to the short window between exploiting the kernel and Debian
admins noticing, the attacker hadn't had time/inclination to cause
much damage.  The only obviously compromised binary was /bin/ping.

The compromised account did not have access to any of the restricted
Debian hosts.  Hence, neither the regular nor the security archive had
a chance to be compromised.

An investigation of developer passwords revealed a number of weak
passwords whose accounts have been locked in response.

The machine status is here: <http://db.debian.org/machines.cgi>

Kernel vulnerability

The kernel vulnerability that has been used for this compromise is
referenced as CVE-2006-2451.  It only exists in the Linux kernel
2.6.13 up to versions before, and 2.6.16 before
The bug allows a local user to gain root privileges via the
PR_SET_DUMPABLE argument of the prctl function and a program that
causes a core dump file to be created in a directory for which the
user does not have permissions.

The current stable release, Debian GNU/Linux 3.1 alias 'sarge',
contains Linux 2.6.8 and is thus not affected by this problem.  The
compromised server ran Linux

If you run Linux 2.6.13 up to versions before, or Linux
2.6.16 up to versions before, please update your kernel

About Debian

Debian GNU/Linux is a free operating system, developed by more than
thousand volunteers from all over the world who collaborate via the
Internet.  Debian's dedication to Free Software, its non-profit nature,
and its open development model make it unique among GNU/Linux

The Debian project's key strengths are its volunteer base, its dedication
to the Debian Social Contract, and its commitment to provide the best
operating system possible.

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