March 4, 2005

Linux Advisory Watch - March 4th 2005

Author: JT Smith

This week, advisories were released for mod_python, bsmtpd, gaim,
bind, gnucash, dhcp, at vixie-cron, lam, pvm, radvd, selinux-targeted-
policy, tcsh, openoffice, gamin, cmd5checkpw, uim, UnAce, MediaWiki,
phpBB, phpWebSite, xli, xloadimage, firefox, squid, kdenetwork,
nvidia, curl, uw-imap, and cyrus-sasl. The distributors include
Conectiva, Debian, Fedora, Gentoo, Red Hat, and SuSE.

By Raymond Ankobia

This is by no means an exhaustive list but an indication of some serious flaws
exploited by hackers. Hacking Exposed: Web Applications (ISBN 007222438X) as
a good source for the subject area.

Buffer Overflow Attack: Usually perpetrated in a form of
stack, heap or format string attack [3]. Without doubt, one of the oldest problems
exposed by poor programming; yet attacks continue to be perpetrated on large
scale, simply due to lack of rigorous security routines in web applications.
To get the system to run their own code, attackers construct an input string
sometimes with other malicious code that is long enough to overrun memory space
assigned to it [7]. By doing so, this spills over and overwrites the stack below,
overwriting what was initially in that address space. If the code contains malicious
payload, it may subvert the system and escalate any privileges it may have garnered.

SQL Injection Attack: Most e-commerce web sites use dynamic
content to attract and appeal to potential customers by displaying their wares
using dynamic SQL queries and front-end scripts. An attacker could inject special
characters and commands into a SQL database and modify the intended query. Chaining
additional commands with intent of causing unexpected behavior could alter the
meaning to a query. Not only could the attacker be able to read the entire database,
but also in some circumstances, alter prices of these commodities.

Cross Site Scripting Attack: (XSS Attacks) This attack is
executed by embedding malicious message in an HTML form [4] [3] and posting
it as a message to say a newsgroup or bulletin board. By viewing the message,
the user unintentionally gets the code interpreted and executed by the web browser
triggering its associated payload.

Input Validation Attack: Typically used by most active attackers
to check for client side validation of fields and if successful then try to
escalate privileges gained [3]. Poorly validated client-side (typically a web
browser) allows an attacker to tamper with parameters sent to the server. Server-side
may also compromised if trust is implicit and validation poorly executed from
the client-side.

Phishing Attack: This attack is mainly executed due to vulnerability
in some versions of web browsers. Attackers are able to create bogus websites
and masquerade as legitimate commercial ones. They normally operate by sending
spoofed emails to unsuspecting customers, advising them to visit their bank's
website to reactivate or update their accounts. The embedded addresses in these
emails tend to have some hidden characters cleverly constructed to make the
page appear to be a legitimate one. On clicking the embedded website address,
the unsuspecting user is redirected to a fake website where the credentials
and details of bank accounts are taken and later used to empty the accounts.

[4] This anomaly is due to obfuscation techniques used by the URL to parse information. URL may be parsed in different ways using
decimal, hexadecimal and dWord format. A particular vulnerability in Internet explorer allowed an attacker to construct and hide
information by simply using the @ symbol in ways that makes it possible to redirect traffic to bogus sites.

Mobile code: Most common languages used for developing mobile
code include Java, ActiveX control and Shockwave. Traditionally the programme
gets downloaded from a web server onto the customers machine. Environments
used for execution include Virtual Machines (in browsers) or downloadable plug-ins.
These programmes could be maliciously crafted to subvert the security and system
functionality by causing crashes and disruption of normal operating environment.

Insecure Configuration Management: The communicating parties
end points, especially their web servers, are poorly configured. Often ignored,
but the area most attacked by hackers as a way of bypassing security offered
by encryption and other security mechanisms [4]. Apache and IIS dominate commercial
deployment of web servers and some of the earlier releases are riddled with
bugs. Simply installing these applications with default settings is a bad practice.
Poorly programmed sample scripts are exploited by attackers who may easily take
control of the server resources.

Google Hacking: Google's search engine traverses the Internet,
crawling websites, and taking snapshots of each web page it examines and caches
its results. Next time a query is received, the search is performed on these
cached pages, allowing for faster retrieval [4]. Hackers exploit these caches
for vulnerable sites. The mechanism used by Google is explained in great depth
in a white paper written by Foundstone (
called SiteDigger,. Tools such as these are the Swiss army knives of hackers.
Using search engines, hackers find vulnerability scanning reports and intrusion
detection alerts and log files. These are then used to find suitable targets
to exploit.

Read full feature:
Feature Extras:

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.

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.

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
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

  Conectiva: mod_python Fix for mod_python
  2nd, March, 2005

The package mod_python[1] provides an Apache module that embeds
the Python interpreter within the server. This annoucement fixes an information
leak vulnerability[2] in mod_python which could allow a remote attacker
to obtain access to restricted objects via a specially crafted URL.

  Debian: New bsmtpd packages fix arbitrary
command execution
  25th, February, 2005

Updated package.

  Fedora Core 2 Update: gaim-1.1.4-0.FC2
  25th, February, 2005

This update resolves another DoS issue in parsing malformed
HTML, and a MSN related crash that folks were hitting often.

  Fedora Core 3 Update: gaim-1.1.4-0.FC3
  25th, February, 2005

This update resolves another DoS issue in parsing malformed
HTML, and a MSN related crash that folks were hitting often.

  Fedora Core 3 Update: bind-9.2.5rc1-1
  25th, February, 2005

Upgraded to ISC BIND version 9.2.5rc1 . Added support for LDAP,
PostgreSQL and filesystem Simplified Database Backends (SDB) with the
bind-sdb package, and for development with libbind, the BIND 8 compatible
resolver library, with the bind-libbind-devel package. Fixed various bugs
(see ChangeLog below).

  Fedora Core 3 Update: gnucash-1.8.11-0.fc3
  25th, February, 2005

This update updates gnucash to the latest upstream release,
1.8.11. This also includes: - update of libofx to 0.7.0 - switching of
the HBCI backend from openhbci to gwenhywfar/aqbanking/aqhbci

  Fedora Core 3 Update: dhcp-3.0.1-40_FC3
  25th, February, 2005

Updated package.

  Fedora Core 3 Update: at-3.1.8-64_FC3
  25th, February, 2005

at(1) now supports access control with PAM (limits.conf, access.conf).

  Fedora Core 3 Update: vixie-cron-4.1-24_FC3
  25th, February, 2005

Updated package.

  Fedora Core 3 Update: lam-7.1.1-1_FC3
  25th, February, 2005

Updated package.

  Fedora Core 3 Update: pvm-3.4.5-2_FC3
  25th, February, 2005

Updated package.

  Fedora Core 3 Update: radvd-0.7.3-1_FC3
  25th, February, 2005

Upgrade to new upstream version 0.7.3 .

  Fedora Core 3 Update: selinux-policy-targeted-1.17.30-2.83
  28th, February, 2005

Updated packages.

  Fedora Core 3 Update: firefox-1.0.1-1.3.1
  28th, February, 2005

This update fixes several security vulnerabilities in Firefox
1.0. It is recommended that all users update to Firefox 1.0.1. Additionally,
this update backports several fixes from rawhide.

  Fedora Core 3 Update: tcsh-6.13-10.FC3.1
  28th, February, 2005

This update fixes incorrect message output under certain locales
in new mail notification, changing resource limits and listing possible

  Fedora Core 3 Update:
  28th, February, 2005

Fix individual programs not launching.

  Fedora Core 3 Update: gamin-0.0.25-1.FC3
  2nd, March, 2005

This release fixes some problems with gamin-0.0.24 especially
for temporary storage like USB keys.

  Gentoo: cmd5checkpw Local password leak
  25th, February, 2005

cmd5checkpw contains a flaw allowing local users to access other
users cmd5checkpw passwords.

  Gentoo: uim Privilege escalation vulnerability
  28th, February, 2005

Under certain conditions, applications linked against uim suffer
from a privilege escalation vulnerability.

  Gentoo: UnAce Buffer overflow and directory
traversal vulnerabilities
  28th, February, 2005

UnAce is vulnerable to several buffer overflow and directory
traversal attacks.

  Gentoo: MediaWiki Multiple vulnerabilities
  28th, February, 2005

MediaWiki is vulnerable to cross-site scripting, data manipulation
and security bypass attacks.

  Gentoo: phpBB Multiple vulnerabilities
  1st, March, 2005

Several vulnerabilities allow remote attackers to gain phpBB
administrator rights or expose and manipulate sensitive data.

  Gentoo: Gaim Multiple Denial of Service
  1st, March, 2005

Multiple vulnerabilities have been found in Gaim which could
allow a remote attacker to crash the application.

  Gentoo: phpWebSite Arbitrary PHP execution
and path disclosure
  1st, March, 2005

Remote attackers can upload and execute arbitrary PHP scripts,
another flaw reveals the full path of scripts.

  Gentoo: xli, xloadimage Multiple vulnerabilities
  2nd, March, 2005

xli and xloadimage are vulnerable to multiple issues, potentially
leading to the execution of arbitrary code.

  RedHat: Critical: firefox security update
  1st, March, 2005

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

  RedHat: Moderate: squid security update
  3rd, March, 2005

Updated squid packages that fix a denial of service issue are
now available. This update has been rated as having important security
impact by the Red Hat Security Response Team

  RedHat: Low: kdenetwork security update
  3rd, March, 2005

Updated kdenetwork packages that fix a file descriptor leak
are now available. This update has been rated as having low security impact
by the Red Hat Security Response Team

  SuSE: kernel / nvidia bugfix update
  25th, February, 2005

The previous kernel security update for the SUSE Linux 9.1 and
the SUSE Linux Enterprise Server 9 based products caused problems with
the NVidia driver for users with NVidia graphics cards.

  SuSE: curl buffer overflow in NTLM
  28th, February, 2005 reported a vulnerability in libcurl,
the HTTP/FTP retrieval library. This library is used by lots of programs,
including YaST2 and PHP4.

  SuSE: uw-imap authentication bypass
  1st, March, 2005

The University of Washington imap daemon can be used to access
mails remotely using the IMAP protocol. This update fixes a logical error
in the challenge response authentication mechanism CRAM-MD5 used by UW
IMAP. Due to this mistake a remote attacker can gain access to the IMAP
server as arbitrary user.

  SuSE: cyrus-sasl remote code execution
  3rd, March, 2005

A buffer overflow in the digestmda5 code was identified that
could lead to a remote attacker executing code in the context of the service
using sasl authentication.

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