Linux Advisory Watch – October 14, 2005

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Author: Benjamin D. Thomas

This week, advisories were released for mason, cpio, dia, masqmail, shorewall,
tcpdump, openvpn, up-imapproxy, ethereal, weex, py2play, graphviz, xloadimage,
xli, xine-lib, hylafax, Ruby, SVG, hexlix player, uw-imap, openssl, thunderbird,
binutils, and libuser. The distributors include Debian, Gentoo, and Red Hat.System Accounting
Dave Wreski
It is very important that the information that comes from syslog not be compromised.
Making the files in /var/log readable and writable by only a limited number of
users is a good start.

Be sure to keep an eye on what gets written there, especially under
the auth facility. Multiple login failures, for example, can indicate
an attempted break-in.

Where to look for your log file will depend on your distribution. In a
Linux system that conforms to the “Linux Filesystem Standard”, such as
Red Hat, you will want to look in /var/log and check messages, mail.log,
and others.

You can find out where your distribution is logging to by looking at
your /etc/syslog.conf file. This is the file that tells syslogd (the
system logging daemon) where to log various messages.

You might also want to configure your log-rotating script or daemon
to keep logs around longer so you have time to examine them. Take a
look at the logrotate package on recent Red Hat distributions. Other
distributions likely have a similar process.

If your log files have been tampered with, see if you can determine
when the tampering started, and what sort of things appeared to be
tampered with. Are there large periods of time that cannot be accounted
for? Checking backup tapes (if you have any) for untampered log files
is a good idea.

Intruders typically modify log files in order to cover their tracks,
but they should still be checked for strange happenings. You may
notice the intruder attempting to gain entrance, or exploit a program
in order to obtain the root account. You might see log entries before
the intruder has time to modify them.

You should also be sure to separate the auth facility from other log
data, including attempts to switch users using su, login attempts, and
other user accounting information.

If possible, configure syslog to send a copy of the most important data
to a secure system. This will prevent an intruder from covering his
tracks by deleting his login/su/ftp/etc attempts. See the syslog.conf
man page, and refer to the @ option.

Finally, log files are much less useful when no one is reading them. Take
some time out every once in a while to look over your log files, and get a feeling
for what they look like on a normal day. Knowing this can help make unusual
things stand out.

Read more from the Linux Security Howto:
http://www.linuxsecurity.com/docs/LDP/Security-HOWTO/

   Debian
  Debian: New mason packages fix missing
init script
  6th, October, 2005

Updated package.
 
  Debian: New cpio packages fix several
vulnerabilities
  7th, October, 2005

Updated package.
 
  Debian: New dia packages fix arbitrary
code execution
  8th, October, 2005

Updated package.
 
  Debian: New masqmail packages fix several
vulnerabilities
  8th, October, 2005

Updated package.
 
  Debian: New shorewall packages fix firewall
bypass
  8th, October, 2005

Updated package.
 
  Debian: New tcpdump packages fix denial
of service
  9th, October, 2005

Updated package.
 
  Debian: New openvpn packages fix denial
of service
  9th, October, 2005

Updated package.
 
  Debian: New up-imapproxy packages fix
arbitrary code execution
  9th, October, 2005

Updated package.
 
  Debian: New ethereal packages fix several
vulnerabilities
  9th, October, 2005

Updated package.
 
  Debian: New tcpdump packages fix denial
of service
  9th, October, 2005

Updated package.
 
  Debian: New weex packages fix arbitrary
code execution
  10th, October, 2005

Updated package.
 
  Debian: New py2play packages fix arbitrary
code execution
  10th, October, 2005

Updated package.
 
  Debian: New graphviz packages fix insecure
temporary file
  10th, October, 2005

Updated package.
 
  Debian: New xloadimage packages fix arbitrary
code execution
  10th, October, 2005

Updated package.
 
  Debian: New xli packages fix arbitrary
code execution
  10th, October, 2005

Updated package.
 
  Debian: New Ruby packages fix safety
bypass
  11th, October, 2005

Updated package.
 
  Debian: New uw-imap packages fix arbitrary
code execution
  11th, October, 2005

Updated package.
 
  Debian: New Ruby 1.6 packages fix safety
bypass
  11th, October, 2005

Updated package.
 
  Debian: New xine-lib packages fix arbitrary
code execution
  12th, October, 2005

Updated package.
 
  Debian: New Ruby 1.8 packages fix safety
bypass
  13th, October, 2005

Updated package.
 
  Debian: New hylafax packages fix insecure
temporary files
  13th, October, 2005

Updated package.
 
   Gentoo
  Gentoo: Ruby Security bypass vulnerability
  6th, October, 2005

Ruby is vulnerable to a security bypass of the safe level mechanism.
 
  Gentoo: Dia Arbitrary code execution
through SVG import
  6th, October, 2005

Improperly sanitised data in Dia allows remote attackers to
execute arbitrary code.
 
  Gentoo: RealPlayer, Helix Player Format
string vulnerability
  7th, October, 2005

RealPlayer and Helix Player are vulnerable to a format string
vulnerability resulting in the execution of arbitrary code.
 
  Gentoo: xine-lib Format string vulnerability
  8th, October, 2005

xine-lib contains a format string error in CDDB response handling
that may be exploited to execute arbitrary code.
 
  Gentoo: Weex Format string vulnerability
  8th, October, 2005

Weex contains a format string error that may be exploited by
malicious servers to execute arbitrary code.
 
  Gentoo: uw-imap Remote buffer overflow
  11th, October, 2005

uw-imap is vulnerable to remote overflow of a buffer in the
IMAP server leading to execution of arbitrary code.
 
  Gentoo: OpenSSL SSL 2.0 protocol rollback
  12th, October, 2005

When using a specific option, OpenSSL can be forced to fallback
to the less secure SSL 2.0 protocol.
 
   Red
Hat
  RedHat: Important: thunderbird security
update
  6th, October, 2005

An updated thunderbird package that fixes various bugs is now
available for Red Hat Enterprise Linux 4. This update has been rated as
having important security impact by the Red Hat Security Response Team.
 
  RedHat: Low: binutils security update
  11th, October, 2005

An updated binutils package that fixes minor security issues
is now available. This update has been rated as having low security impact
by the Red Hat Security Response Team.
 
  RedHat: Low: libuser security update
  11th, October, 2005

Updated libuser packages that fix various security issues are
now available. This update has been rated as having low security impact
by the Red Hat Security Response Team.
 
  RedHat: Moderate: util-linux and mount
security update
  11th, October, 2005

Updated util-linux and mount packages that fix two security
issues are now available. This update has been rated as having moderate
security impact by the Red Hat Security Response Team.
 
  RedHat: Moderate: ruby security update
  11th, October, 2005

Updated ruby packages that fix an arbitrary command execution
issue are now available. This update has been rated as having moderate
security impact by the Red Hat Security Response Team.
 
  RedHat: Moderate: openssl security update
  11th, October, 2005

Updated OpenSSL packages that fix various security issues are
now available. This update has been rated as having moderate security
impact by the Red Hat Security Response Team.
 

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