How to Use Fcrackzip to Crack Zip Passwords in Kali Linux
Fcrackzip is a tool that can be used to decrypt zip files and determine their passwords. The brute-force method is used in this tool. Fcrackzip is a fast password cracker partly written in assembler and available for Kali Linux. It is able to crack password-protected zip files with brute force or dictionary-based attacks allowing you to unzip files even with most hard passwords.
Fcrackzip Kali Linux
Installation
Fcrackzip is already installed in Kali Linux by default. To verify the installation, you can open the terminal and type fcrackzip --help and the toolÃÂÂs help command will run. If you don't have fcrackzip installed, you can install it with the following commands:
sudo apt update
sudo apt-get install fcrackzip
Usage
To use fcrackzip, you need to specify the zip file that you want to crack and the options that you want to use. The basic syntax of fcrackzip is:
fcrackzip [options] file.zip
The most common options are:
-b: use brute force algorithm
-D: use a dictionary
-c: use characters from charset
-l: check password with length min-max
-u: use unzip to weed out wrong passwords
-v: be more verbose
-p: use string as initial password/file
Examples
Let's see some examples of how to use fcrackzip to crack zip passwords in Kali Linux.
Cracking a zip password with brute force and numeric charset
If you know that the zip password consists of only numbers, you can use the -c '1' option to specify the numeric charset. For example, to crack a zip file named file.zip with brute force and numeric charset, you can use the following command:
fcrackzip -b -c '1' -u file.zip
The -u option will use unzip to test the passwords and show only the correct one. The output will look something like this:
PASSWORD FOUND!!!!: pw == 1234
fcrackzip: trying 0 passwords per second (3 cpus)
Cracking a zip password with dictionary attack
If you have a wordlist or a dictionary file that contains possible passwords, you can use the -D option to specify it. For example, to crack a zip file named file.zip with a dictionary attack using a wordlist named wordlist.txt, you can use the following command:
fcrackzip -D -p wordlist.txt -u file.zip
The output will look something like this:
PASSWORD FOUND!!!!: pw == secret
fcrackzip: trying 0 passwords per second (3 cpus)
Cracking a zip password of a certain length with verbose mode
If you know the length of the zip password, you can use the -l min-max option to specify it. For example, to crack a zip password of length 4 with verbose mode, you can use the following command:
fcrackzip -b -v -l 4-4 -u file.zip
The verbose mode will show more information about the cracking process, such as the file name, size, and the current password combination. The output will look something like this:
fcrackzip: testing luv.txt (size 5 bytes)
trying pw 0000
trying pw 0001
trying pw 0002
...
trying pw 1234
PASSWORD FOUND!!!!: pw == 1234
fcrackzip:
c8f7815bcf