Originally published April 22, 2016 @ 1:11 am
John the Ripper is a free multi-platform password-cracking software. This article is not intended to be a comprehensive guide to jtr, rather a quick how-to. Starting with version 1.7.9, jumbo patch 6, jtr supports password recovery for Office 2007/2010. In the example below, I will compile jtr from source with OpenMP support to take advantage of a multi-CPU server running CentOS 6.
Install OpenMP support and some useful performance-monitoring tools:
yum -y install openmpi openmpi-devel htop nmon openssl openssl-devel
Download and compile jtr version 1.7.9, jumbo patch 7:
cd /tmp wget http://www.openwall.com/john/g/john-1.7.9-jumbo-7.tar.gz tar -xvzf john-1.7.9-jumbo-7.tar.gz /bin/mv john-1.7.9-jumbo-7 /opt/john /bin/rm john-1.7.9-jumbo-7.tar.gz cd /opt/john/src vi Makefile # Uncomment "OMPFLAGS = -fopenmp" and "OMPFLAGS = -fopenmp -msse2" make clean linux-x86-64
Install jtr from standard CentOS repo and copy some missing files:
yum -y install john rsync -av /usr/share/john/ /opt/john/ vi /etc/john.conf # Comment out: .include <dynamic.conf> cd /opt/john /opt/john/run/john |grep ^John /opt/john/run/john --test # Run htop in another window to verify that all CPUs are being utilized # Adjust number of threads: OMP_NUM_THREADS=4 /opt/john/run/john --test
Install office2john Python script to extract hashes from Office files:
mkdir -p /var/adm/bin wget --no-check-certificate -q -O /var/adm/bin/office2john.py https://raw.githubusercontent.com/kholia/RC4-40-brute-office/master/office2john.py chmod 755 /var/adm/bin/office2john.py ln -s /var/adm/bin/office2john.py /usr/bin/office2john
Process an Office file:
office2john /var/tmp/your_file.xlsx | awk -F: '{print $2}' > /var/tmp/your_file.hash
cd /opt/john/run
/opt/john/run/john /var/tmp/your_file.hash &disown
/opt/john/run/john --status
Experienced Unix/Linux System Administrator with 20-year background in Systems Analysis, Problem Resolution and Engineering Application Support in a large distributed Unix and Windows server environment. Strong problem determination skills. Good knowledge of networking, remote diagnostic techniques, firewalls and network security. Extensive experience with engineering application and database servers, high-availability systems, high-performance computing clusters, and process automation.
