• researchJohn the Ripper

    John the Ripper is a multi-platform password cracking tool.

    While the standard distribution package of JtR is already a very capable application, there are several enhancements available which can increase both the variety of crackable encryption schemes, password complexity, and the performance of JtR itself.

    The rest of the chapter will cover both the installation steps for each of the enhancements as well as brief description of their operation. This chapter assumes you have a Linux based system (e.g Ubuntu) all of the necessary compilation and build tools installed.

    First we will need to download and extract complete JtR source code. At the time of this writing the latest version of JtR is 1.7.6.

    tar -xvjf john-1.7.6.tar.bz2

    Next let's download a “Jumbo” patch for the JtR which contains code contributed by the user community. While the contributed code base is not as mature as the original JtR code base, the patch contributes a number of newer encryption and hashing algorithms. Below are the steps to download the patch and apply it to the previously downloaded source.

    gunzip john-1.7.6-jumbo-3.diff.gz
    cd john-1.7.6
    patch -p1 < ../john-1.7.6-jumbo-3.diff

    Note: You have to apply the patch by changing the directory into the extracted source. Another key enhancement that can be performed upon already optimized code is to teach JtR how to operate in multi-processor environments. There are a number of solutions available, but the most reliable of them are all based on the Message Passing Interface (MPI) architecture. First we need to download and setup MPI daemon on the host operating system:

    sudo apt-get install mpich2 libssl-dev

    With the MPI infrastructure installed and running, we can now apply another patch to JtR:

    gunzip john-1.7.6-fullmpi8-after-jumbo3.diff.gz
    cd john-1.7.6
    patch -p1 < ../john-1.7.6-fullmpi8-after-jumbo3.diff

    Note: As you can tell from the patch name, it is designed to be applied after the installation of the “Jumbo” patch.

    The last step in preparing our enhanced JtR installation is to compile it for the specific CPU architecture. This is done by means of special flags appended to the “make” command. For example, to take advantage of 64bit processors append “linux-x86-64”. For 32bit CPUs use “linux-x86-sse2” or “generic”.

    cd john-1.7.6
    cd src
    make linux-x86-64
    sudo make install

    You can now test JtR with full MPI capabilities with the following command line:

    mpiexec -n 4 ~/john-1.7.6/run/john –test

    NOTE: -n 4 defines how many cores to use. Use more or less as needed With all of the enhancements to the John the Ripper, we can now apply a new charset file based on passwords from a recent RockYou compromise. The new charset file will enhance JtR's incremental cracking mode. First, let's download the updated *.chr file:

    cd john-1.7.6
    cd run
    gunzip rockyou.chr.gz

    Next, edit “john.conf” file to include new rules by adding the following lines:

    File = $JOHN/rockyou.chr
    MinLen = 1
    MaxLen = 8
    CharCount = 95

    To execute JtR with a new charset file use the following command line to run John in incremental mode:

    ~/john-1.7.6/run/john --incremental:rockyou passwd

    or with MPI:

    mpiexec -n 4 ~/john-1.7.6/run/john --incremental:rockyou passwd

    Published on August 1st, 2010 by iphelix


    orapass des

    Size 1.6 KB
    DateFebruary 21st, 2009

    Orapass implements Oracle's older DES-based password hashing algorithm. This script can be used for password strength audit and recovery. Uses Python Crypto library. Read more.

    07 aug
    crack me if you can

    I had an opportunity to participate in the "Crack me if you can" password cracking competition during this year's Defcon. It was a fun and educational experience. Using a couple of video cards, decent processors as well as some research into password generation I was able to place 4th in the contest. In this post you can learn more about hardware, software and strategy used to crack about 25k passwords in two days. Read more.

    automatic password rule analysis and generation

    The field of password cracking has evolved by leaps an bounds over the last decade with the introduction of new cracking techniques, more advanced software and significantly faster hardware. One area which I find most fascinating is rule-based cracking. An attacker can develop a set of word mangling rules (e.g. substitute all 'a's to '@'s, upper-case every third letter, etc.) in order to attack non-random passwords which use slightly modified dictionary words. The purpose of this research is to develop an automated method of analyzing a large body of leaked passwords in order to come up with a list of frequently used words and rules to make up passwords. Read more.

    password analysis and cracking kit

    Download PACK-0.0.4.tar.gz
    Size 68.8 KB
    DateAugust 8th, 2013

    PACK (Password Analysis and Cracking Toolkit) is a collection of utilities developed to aid in analysis of password lists and enhancing cracking of passwords using password pattern detection. It can be used to reverse word mangling rules, generate source words, optimize password masks, craft policy attacks, etc. for the Hashcat family of tools. The toolkit itself is not able to crack passwords, but instead designed to make operation of password crackers more efficient. Read more.


    All original content on this site is copyright protected and licensed under Creative Commons - Attribution, NonCommercial, ShareAlike 4.0 International.