Rarcrack cracks compressed file’s passwords

Well, obviously :-P . It is a very useful application for those of you who want to feel more elite than you already are (and this is for Linux only, so you have to be at least minimally elite already) or have a file you received/ torrent you downloaded but can’t get the password anywhere, you may want to check this out.

It can crack up to 12 combos of either letters, numbers or both. It starts off by trying all the two letter combinations and then moves it’s way up until the final 12. It can take a while to move up from three to four to five etcetera combinations, but you can specify a starting number of characters to try which can save considerable amounts of time.

My friend David sent me a file with special characters which couldn’t be deciphered by Rarcrack thus rendering it useless for files as such. It at the moment (or from what I’ve noticed from it’s probing feedback) doesn’t try things such as the underscore which could also render it pointless with certain files.

It is run from the command line and I like the output it relays to you so you can see it’s progress and will give you the final correct password after it finds it under the words “GOOD” :-D . It creates an .xml file with a little bit of info on Rarcrack and the encrypted file that it broke through.

To install Rarcrack, you’ll need to head on over to it’s page at Sourceforge which I’ll add at the end of this paragraph. You just need to grab the g-zipped file right here and extract it to wherever (I’d suggest putting it in the home folder as you need to keep the folder) and then run the following instructions:
http://sourceforge.net/projects/rarcrack/

Once done, open up a terminal window and change your directory to it’s containment then run make. It will compile and possibly output a “warning”, but you can ignore that. After that just install it with sudo make install.

To get a feel of what it feels like to watch a file get decrypted, just test out one of the three file types it can decrypt (.rar, .zip, .7z) by running something like the example I’ll provide below in the directory the file is in:
rarcrack something.rar

You can add certain subcommands which can be found by typing rarcack –help, my favorite being threads which specifies the starting number of characters to work up on greatly saving time.

Well, I do hope you enjoy this and play around although a few features limit how well and much you’ll be using it and for what. The current release is 0.2 so expect a lot more coming up soon as the developer upgrades this.

Enjoy!
nikoPSK

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~ by nikopsk on April 16, 2008.

5 Responses to “Rarcrack cracks compressed file’s passwords”

  1. Hi Niko.. I enjoy reading your informative blogs. :) As you discovered, Rarcrack does take a while to crack nine character passwords like “alligator”. :P Did you ever get that test file I sent you cracked? :o

  2. Sounds interesting.
    This is another good reason why to encrypt your files / archives with your GPG Public key ;)

    It is a shame you couldn’t specify a wordlist for cracking (or can you? ;) ). It would drastically cut down on cracking time. John the Ripper uses wordlists too, and I have several of them to aid me along :)

  3. I believe you can add the the .xml it creates as it outputs all the default characters; but I haven’t yet tested. And Tom, yes I did. :-D

  4. Hello, I just found out about rarcrack, but i feel i might be doing something wrong. . .when i use it i get “Segmentation fault “. Any ideas? Can you help?

  5. This is a known bug. Provide type:

    rarcrack whatever.rar –threads 4 –type rar

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