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26

Jul

2010

Kraken – GSM A5 Cracking

By IPSECS Admin. Posted in Exploitation, News | No Comments »

GSM A5 Cracking topic is started to be public material since The Hacker Choice disclosed their research. Many open source materials related to GSM are released to the public on Osmocomm. Now, tool called Kraken is freely distributed on internet to crack GSM A5.

I am pleased to announce the first release of a A5/1 cracker capable
using the full Berlin set of rainbow tables for lookups. I have named
this beast Kraken, after a Norse mythological creature capable of eating
many things for breakfast. Kraken feeds of an exclusive diet of A5/1
encrypted data.

Currently only a bare bone functionality is present, but the UI will be
improved, with the specific goal of providing an easy to use tool for
cracking GSM intercepts. But setting up this Leviathan can a bit
cumbersome, so I will give a short howto here:

Prerequisites:

* Linux machine, multicore min 3GB RAM
* 1.7 - 2TB of HD partitions without filsystem ( ex Samsung spinpoint F3s,
  with 4k aligned start of partition )
* The Berlin A5/1 Rainbow table set
* GPU support will be added for ATI Radeon HD

Setup:

Find out how many tables you want on each partition, (usually roughly
equal on each) and make the initial configuration file. An example
configuration folder can be found in tinkering/A5Util/indexes. This
folder should contain a tables.conf file. The example files shows a
setup of 4 disk having 10 tables each. The index files for the various
tables will be added to the index folder as they are written to disk.
The first section of the config file needs to be set up with the list of
available partitions, and the number of tables that each partition
should hold. A single table needs 42GB of space. (Do NOT change the
order of this section)

For safety reasons it is best not to build the tables running as root.
The you will then have to make your table partitions user accessible.
Add a file such as 10-disk.rules in /etc/udev/rules.d with one line for
each partition:

KERNEL=="sda1", OWNER="frank"

Then manually change the ownership of the device nodes with chown. Take
care when doing this, as you do not want to nuke any of your system
partitions.

Add tables to your disk array:

First build and make a symlink from your index folder to the
TableConvert tool. It is assumed that the Berlin tables are available in
either SSD or index free delta format. The python script Behemoth.py
will recursively search for tables, and add them to the disk array and
configuration file as needed. (Duplicates will not be added) - This
operation(s) will take some hours to complete, but when done you should
end up with a tables.conf file listing ~40 tables, their advance
parameter (id), which device they reside on, and a block offset into the
device.

Build and fire up Kraken:

./kraken path_to_index_folder

Currently it will only load up all tables, and crack TDMA burst 998 for
the challenge data. This takes 1.5 minutes on a 4 core Phenom II using
only CPU power, and the output should look like:

Cracking
0011011100110000000010000011000110001001101101100110110100111100011010
10100100101111111010111100000110101001101011
Found de6bb5e60617f95c @ 12
Found 6fb7905579e28bfc @ 23

A more interactive UI with appropriate data formats (representations)
will be added for easy interfacing with airprobe. Optional GPU support
will also be added for faster cracking time.

cheers,
Frank

Source : http://lists.lists.reflextor.com/pipermail/a51/2010-July/000683.html

Well the article form http://computerworld.com is really nice to read!

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9

Jun

2009

Distributed Password Cracking

By IPSECS Admin. Posted in Exploitation, Presentation | No Comments »

Password cracking which uses some computers to accelerate password cracking process. It usually uses computer clusters and some software to support parallel computing. Some known software to do parallel computing in cluster computers are:

  • John The Ripper and Condor, John works as password cracker while Condor works as scheduler which parallelizes cracking proccess and distributes it to clusters.
  • John The Ripper and Djohn, John works as password cracker while Djohn works as client-servers application which parallelizes cracking proccess and distributes it to clusters.
  • Medussa, password cracker which’s originally designed to do parallel password cracking. It contains client servers application to parallelize cracking proccess and distribute it to clusters.
  • John The Ripper with MPI patch, john which’s developed using MPI programming. MPI is standard de facto for parallel programming which’s implemented on some softwares i.e : OpenMPI, MPICH, and LAM/MPI.

Our presentation describes how to do parallel cracking using John The Ripper with MPI patch. We use 15 dual core computers and LAM/MPI in distributing cracking proccess. Download our presentation here.

 

Introduction

802.1x is an IEEE standard for port-based (well, we would rather say interface-based) enduser authentication on LANs. While it supports (and was initially designed for) Ethernet, the main current use of 802.1x is wireless users’ authentication as a part of the wireless security scheme provided by the 802.11i security standard. The 802.1x authentication chain consists of three elements:

  • Supplicant An end-user station, often a laptop, that runs 802.1x client software.
  • Authenticator A switch, a wireless gateway, or an access point to which the authenticating users connect. It must be configured to support 802.1x on the involved interfaces with commands like aaa authentication dot1x default group radius (global configuration) and dot1x port control auto (switch interface).
  • Authentication server A RADIUS server to which authenticators forward end users’ authentication requests for verification and authentication decision.

Cisco Switch

EAP-LEAP Basics

The Extensible Authentication Protocol (EAP) is used by all three 802.1x component devices to communicate with each other. It is extensible since many different EAP types exist for all kinds of authentication plans—for example, employing SIM cards, tokens, certificates, and more traditional passwords. Here we are interested only in Cisco-related protocols and products, thus the security weaknesses of EAP-LEAP are the target of the discussion.

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