June 17, 2005

Linux Advisory Watch - June 17, 2005

Author: Benjamin D. Thomas

This week, advisories were released for mikmod, tcpdump, yum, elinks, parted,
system-config-securitylevel, checkpolicy, spamassassin, gaim, libextractor,
Ettercap, shtool, gedit, MediaWiki, gzip, gftp, squid, rsh, sysreport, telnet,
bz, and mc. The distributors include Fedora, Gentoo, and Red Hat.SPF: Ready for Prime Time?
by Pete O'Hara

Introduction

As of the time of this writing in the fight against SPAM a policy has
been drafted to target sender address forging called SPF (Sender Policy
Framework). The basic premise is to verify that the sender of an email
is in fact who they by claim to be. If they are not then mail can be
rejected. This could potentially eliminate a big percentage of SPAM and
who wouldn't want that.. But there have been problems with SPF and it
isn't the big solution that everyone had imagined when it first hit
the scene. There are a couple of plaguing issues that keep it from
becoming a mature solution with a standard.

What is SPF?

The first version of SPF (also know as "Classic" SPF) was a creation
of Meng Wong, founder of Pobox.com. In short the scheme is based on
domains publishing what servers are allowed to send mail for
themselves using DNS TXT records. A receiving MTA can then look at
the domain the sender is claiming to be from and the IP address of
the connecting client and check the SPF (DNS TXT) record for that
domain and verify if the client is allowed to send mail for the said
domain. From the results the receiving MTA can take appropriate actions.
The goal is to prevent sender forgery, one of the most common
characteristics of spam. SPF was a proposal considered by IETF's
MARID group.

Summary

I, as everyone else, would love to be able to block all SPAM and I
certainly applaud all of the efforts that have been and are still
being made. But it seems obvious that SPF alone isn't going to be
the answer. It doesn't handle the forwarding issue and SRS isn't
ready as a solution. One could argue that SPF can at least be used
not to reject mail but to whitelist mail from senders that pass SPF
checks. In view of spammers deploying SPF themselves this would
actually be counter productive as it gives them a form of credibility.

Based on the material presented here there are options other than
standalone SPF that on the surface seem to provide a better solution
but the cost is that they are more complex in that they require
reputation/accreditation services. But does the lack of agreement
on the simpler SPF (which turned out to be not so simple once the
forwarding issues surfaced) foreshadow the difficulties in
standardizing more elaborate proposals? If the trend towards
reputation/accreditation gains momentum, which by the way would
still require some form of sender validation to be established (you
can't build a dependable reputation of a sender when it can't be
verified), harmony on the architecture of such services seems a very
long way off. Sender verification is a problem that certainly needs
to be addressed but SMTP wasn't originally designed with this
functionality in mind. Therefore a viable solution is not going to
be as simple as publishing DNS records of authorized mail servers.
SPF on it's own isn't the answer.

Read Entire Article:
http://infocenter.guardiandigital.com/documentatio n/spf.html


LinuxSecurity.com
Feature Extras:

Getting
to Know Linux Security: File Permissions
- Welcome to the first
tutorial in the 'Getting to Know Linux Security' series. The topic explored
is Linux file permissions. It offers an easy to follow explanation of how
to read permissions, and how to set them using chmod. This guide is intended
for users new to Linux security, therefore very simple. If the feedback is
good, I'll consider creating more complex guides for advanced users. Please
let us know what you think and how these can be improved.

The
Tao of Network Security Monitoring: Beyond Intrusion Detection

- To be honest, this was one of the best books that I've read on network security.
Others books often dive so deeply into technical discussions, they fail to
provide any relevance to network engineers/administrators working in a corporate
environment. Budgets, deadlines, and flexibility are issues that we must all
address. The Tao of Network Security Monitoring is presented in such a way
that all of these are still relevant.

Encrypting
Shell Scripts
- Do you have scripts that contain sensitive information
like passwords and you pretty much depend on file permissions to keep it secure?
If so, then that type of security is good provided you keep your system secure
and some user doesn't have a "ps -ef" loop running in an attempt to capture
that sensitive info (though some applications mask passwords in "ps" output).

 

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Thank you for reading the LinuxSecurity.com
weekly security newsletter. The purpose of this document is to provide our readers
with a quick summary of each week's most relevant Linux security headline
.


   Fedora
  Fedora Core 3 Update: mikmod-3.1.6-31.FC3
  9th, June, 2005
 
  Fedora Core 3 Update: tcpdump-3.8.2-9.FC3
  9th, June, 2005
 
  Fedora Core 3 Update: yum-2.2.1-0.fc3
  13th, June, 2005
 
  Fedora Core 4 Update: elinks-0.10.3-3.1
  16th, June, 2005
 
  Fedora Core 4 Update: mikmod-3.1.6-35.FC4
  16th, June, 2005
 
  Fedora Core 4 Update: tcpdump-3.8.2-13.FC4
  16th, June, 2005
 
  Fedora Core 4 Update: parted-1.6.22-3.FC4
  16th, June, 2005
 
  Fedora Core 4 Update: system-config-securitylevel-1.5.8.1-1
  16th, June, 2005
 
  Fedora Core 3 Update: checkpolicy-1.17.5-1.2
  16th, June, 2005
 
  Fedora Core 3 Update: selinux-policy-targeted-1.17.30-3.9
  16th, June, 2005
 
  Fedora Core 3 Update: spamassassin-3.0.4-1.fc3
  16th, June, 2005
Important update for a Denial of Service vulnerability, plus
more bug fixes from upstream. More details available at: http://wiki.apache.org/spamassassin/NextRelease
http://www.linuxsecurity.com/content/view/119332
 
  Fedora Core 4 Update: spamassassin-3.0.4-1.fc4
  16th, June, 2005
Important update for a Denial of Service vulnerability, plus
more bug fixes from upstream. More details available at: http://wiki.apache.org/spamassassin/NextRelease
http://www.linuxsecurity.com/content/view/119333
 
  Fedora Core 3 Update: gaim-1.3.1-0.fc3
  16th, June, 2005
More bug and denial of service fixes. http://www.linuxsecurity.com/content/view/119334
 
  Fedora Core 4 Update: gaim-1.3.1-0.fc4
  16th, June, 2005
More bug and denial of service fixes. http://www.linuxsecurity.com/content/view/119335
 
   Gentoo
  Gentoo: libextractor Multiple overflow
vulnerabilities
  9th, June, 2005
libextractor is affected by several overflow vulnerabilities
in the PDF, Real and PNG extractors, making it vulnerable to execution
of arbitrary code. http://www.linuxsecurity.com/content/view/119279
 
  Gentoo: Ettercap Format string vulnerability
  11th, June, 2005
A format string vulnerability in Ettercap could allow a remote
attacker to execute arbitrary code. http://www.linuxsecurity.com/content/view/119283
 
  Gentoo: GNU shtool, ocaml-mysql Insecure
temporary file
  11th, June, 2005
GNU shtool and ocaml-mysql are vulnerable to symlink attacks,
potentially allowing a local user to overwrite arbitrary files. http://www.linuxsecurity.com/content/view/119284
 
  Gentoo: gedit Format string vulnerability
  11th, June, 2005
gedit suffers from a format string vulnerability that could
allow arbitrary code execution. http://www.linuxsecurity.com/content/view/119285
 
  Gentoo: GNU shtool, ocaml-mysql Insecure
temporary file
  11th, June, 2005
GNU shtool and ocaml-mysql are vulnerable to symlink attacks,
potentially allowing a local user to overwrite arbitrary files. http://www.linuxsecurity.com/content/view/119286
 
  Gentoo: LutelWall Insecure temporary
file creation
  11th, June, 2005
LutelWall is vulnerable to symlink attacks, potentially allowing
a local user to overwrite arbitrary files. http://www.linuxsecurity.com/content/view/119287
 
  Gentoo: Ettercap Format string vulnerability
  11th, June, 2005
A format string vulnerability in Ettercap could allow a remote
attacker to execute arbitrary code. http://www.linuxsecurity.com/content/view/119288
 
  Gentoo: Gaim Denial of Service vulnerabilities
  12th, June, 2005
Gaim contains two remote Denial of Service vulnerabilities.
http://www.linuxsecurity.com/content/view/119290
 
  Gentoo: TCPDump Decoding routines Denial
of Service
  13th, June, 2005
While working on the tcpdump issues solved in the original version
of this GLSA, Simon L. Nielsen from FreeBSD Security Team discovered a
similar infinite loop DoS vulnerability in the BGP handling code (CAN-2005-1267).
http://www.linuxsecurity.com/content/view/119305
 
  Gentoo: MediaWiki Cross-site scripting
vulnerability
  13th, June, 2005
MediaWiki is vulnerable to a cross-site scripting attack that
could allow arbitrary scripting code execution. http://www.linuxsecurity.com/content/view/119306
 
   Red Hat
  RedHat: Low: gzip security update
  13th, June, 2005
An updated gzip package is now available. This update has been
rated as having low security impact by the Red Hat Security Response Team.
http://www.linuxsecurity.com/content/view/119295
 
  RedHat: Moderate: gftp security update
  13th, June, 2005
An updated gFTP package that fixes a directory traversal issue
is now available. This update has been rated as having moderate security
impact by the Red Hat Security Response Team. http://www.linuxsecurity.com/content/view/119296
 
  RedHat: Low: squid security update
  13th, June, 2005
An updated squid package that fixes several security issues
is now available. This update has been rated as having low security impact
by the Red Hat Security Response Team. http://www.linuxsecurity.com/content/view/119297
 
  RedHat: Low: rsh security update
  13th, June, 2005
Updated rsh packages that fix a theoretical security issue are
now available. This update has been rated as having low security impact
by the Red Hat Security Response Team http://www.linuxsecurity.com/content/view/119298
 
  RedHat: Moderate: gedit security update
  13th, June, 2005
An updated gedit package that fixes a file name format string
vulnerability is now available. This update has been rated as having moderate
security impact by the Red Hat Security Response Team http://www.linuxsecurity.com/content/view/119299
 
  RedHat: Moderate: sysreport security
update
  13th, June, 2005
An updated sysreport package that fixes an information disclosure
flaw is now available. This update has been rated as having moderate security
impact by the Red Hat Security Response Team http://www.linuxsecurity.com/content/view/119300
 
  RedHat: Low: tcpdump security update
  13th, June, 2005
Updated tcpdump packages that fix a security issue are now available.
This update has been rated as having low security impact by the Red Hat
Security Response Team. http://www.linuxsecurity.com/content/view/119301
 
  RedHat: Low: mikmod security update
  13th, June, 2005
Updated mikmod packages that fix a security issue are now available.
This update has been rated as having low security impact by the Red Hat
Security Response Team. http://www.linuxsecurity.com/content/view/119302
 
  RedHat: Low: squid security update
  14th, June, 2005
An updated squid package that fixes several security issues
is now available. This update has been rated as having low security impact
by the Red Hat Security Response Team. http://www.linuxsecurity.com/content/view/119312
 
  RedHat: Moderate: telnet security update
  14th, June, 2005
Updated telnet packages that fix an information disclosure issue
are now available. This update has been rated as having moderate security
impact by the Red Hat Security Response Team. http://www.linuxsecurity.com/content/view/119313
 
  RedHat: Low: bzip2 security update
  16th, June, 2005
Updated bzip2 packages that fix multiple issues are now available.
This update has been rated as having low security impact by the Red Hat
Security Response Team. http://www.linuxsecurity.com/content/view/119329
 
  RedHat: Moderate: mc security update
  16th, June, 2005
Updated mc packages that fix several security issues are now
available for Red Hat Enterprise Linux 2.1. This update has been rated
as having moderate security impact by the Red Hat Security Response Team.
http://www.linuxsecurity.com/content/view/119330
 
  RedHat: Moderate: gaim security update
  16th, June, 2005
An updated gaim package that fixes two denial of service issues
is now available. This update has been rated as having moderate security
impact by the Red Hat Security Response Team. http://www.linuxsecurity.com/content/view/119331
 
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