After seeing how to compile John the Ripper to use all your computer's processors now we can use it for some tasks that may be useful to digital forensic investigators: getting around passwords. Today we will focus on cracking passwords for ZIP and RAR archive files. Luckily, the JtR community has done most of the hard work for us. For this to work you need to have built the community version of John the Ripper since it has extra utilities for ZIP and RAR files.
For this exercise I have created password protected RAR and ZIP files, that each contain two files.
Cracking WPA-PSK/WPA2-PSK with John the Ripper John is able to crack WPA-PSK and WPA2-PSK passwords. Recent changes have improved performance when there are multiple hashes in the input file, that have the same SSID (the routers 'name' string). John the Ripper can also crack UNIX/Linux passwords. You need root access to your system and to the password (/etc/passwd) and shadow password (/etc/shadow) files. Perform the following steps for cracking UNIX/Linux passwords: Download the UNIX source files from www.openwall.com/john. John is able to take dozens of different password hashes, pilfered from the SAM database or shadow file, and attempt to crack them. There are four different modes you may use to best crack password. The example username and hashes provided in the pass.txt file to john. Incremental – Brute force attack. ”John the Ripper” – is a fast password cracker. Its primary purpose is to detect weak Unix passwords. Most likely you do not need to install “John the Ripper” system-wide. Instead, after you extract the distribution archive and possibly compile the source code (see below), you may simply enter the “run” directory and invoke John. After locating the folder of john the ripper select john.exe, it will be like this: Now that both are connected to each other you can start hacking passwords with the GUI interface. For this demo tutorial, we will be using the DEFCON challenge list which is a listed of hashed passwords we need to crack.
The password for the rar file is 'test1234' and the password for the zip file is 'test4321'.
Crack Htpasswd John The Ripper No Password Hashes Loaded
In the 'run' folder of John the Ripper community version (I am using John-1.7.9-jumbo-7), there are two programs called 'zip2john' and 'rar2john'. Run them against their respective file types to extract the password hashes:
This will give you files that contain the password hashes to be cracked... something like this:
After, that you can run John the Ripper directly on the password hash files:
You should get a message like:
Loaded 1 password hash (PKZIP [32/64])Crack Htpasswd John The Ripper No Password Reset
. By using John with no options it will use its default order of cracking modes. See the examples page for more information on modes.Notice, in this case we are not using explicit dictionaries. You could potentially speed the cracking process up if you have an idea what the password may be. If you look at your processor usage, if only one is maxed out, then you did not enable OpenMP when building. If you have a multi-processor system, it will greatly speed up the cracking process.
Now sit back and wait for the cracking to finish. On a 64bit quad-core i7 system, without using GPU, and while doing some other CPU-intensive tasks, the password was cracked in 6.5 hours.
Now if you want to see the cracked passwords give john the following arguments:
It should output something like:
Note: the hash file should have the same type of hashes. For example, we cannot put the rar AND zip hashes in the same file. But this means you could try to crack more than one zip/rar file at a time.
For the rar file it did not take nearly as long since the password was relatively common. If you take a look at john.conf in the run directory, it has a list of the patterns it checks (in order). The pattern 12345 is much more likely than 54321, so it is checked first resulting in a quick crack.