Home page logo

bugtraq logo Bugtraq mailing list archives

Nstxd vulnerability
From: laurent oudot <oudot () rstack org>
Date: 26 Mar 2004 22:27:37 -0000

            Rstack Team (Rstack.org) --- Security Advisory 

Advisory Number: RSTACK-20040325 
Subject: Nstxd remote DoS-Bug (NULL-pointer-dereference)
Author: Laurent Oudot <oudot () rstack org> 
Discovered: ...
Published: March 25, 2004

Problem description 

Nstxd is the server from the Nstx project. Nstx can be used to create 
IP trafic over DNS (can be used by blackhats for special Wifi networks 
with DNS open for everybody).
Unexpected input may crash the server called nstxd which will at least 
result in a DOS due to a NULL-pointer-dereference. 
The service nstxd runs as root to bind the UDP port 53.

Vulnerable versions 

Tests were done with the latest version : nstx-1.1-beta3

Vendor status 

The Nstx team quickly solved this bug.
A new release is available : nstx-1.1-beta4.

From the ChangeLog :
    1.1-beta4: sky
    * Fixed a remote DoS-Bug (NULL-pointer-dereference)


* Upgrade your Nstx version at :

* Workaround: Containment (chroot, jail...) and low level security 
  solutions (grsecurity, systrace...) should be use to improve 
  the security of such a server.


** On the server (assume the IP is for this example):
nstx-1.1-beta3# ./nstxd tun.mydomain.com

** On a remote "evil" client:
remote-hacker$ perl -e '{ print "A" x 500 }' | nc -u 53

This will segfault the server.
It might be dangerous as nstxd needs root priviledges (bind port 53).
No exploit to get a remote shell has been reported (just a DOS).

Copyright (c) Rstack Team
This document is copyrighted. It can't be edited nor republished 
without explicit consent of Rstack Team. 
For more informations, feel free to contact us. 

  By Date           By Thread  

Current thread:
  • Nstxd vulnerability laurent oudot (Mar 26)
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]