11

I think I already know the answer to this question, but I thought I'd ask the experts anyway.

A few months back, I created a password-protected 7-Zip archive which housed the source code of a simple program I was writing at the time. I was using the archive everyday, and so never wrote the password down. I've been racking my brain since finding the archive on my hard drive earlier in the week trying to remember the password, but I'm sure it's long forgotten.

I was wondering if there is any way to brute-force this password, or if it is even possible?

The password is at probably 4-13 chars long, and more than likely alpha-numeric with symbols too. It doesn't contain essential files, but I'd like to recover the code if at all possible.

  • 4 to 13 characters means your range is somewhere between 1-in-14million and 1-in-10^^25. So that's somewhere between easy and totally impossible. – tylerl Feb 20 '14 at 3:04
12

If it's a 4 character password, you can do it. If it's 13, good luck.

Rarcrack, under the GPLv2 license, is one of the few cracking packages that has a mode for 7z files at this time.

  • A tip from MyDigitalLife.info shows that if you start rarcrack once, then stop it, you can edit the abc element of its XML config/status file to limit the character set it searches.

  • If there are any characters you can eliminate, do so; it'll shrink the keyspace significantly.

If you're reading this thread after March 2014, see if there's a version of John the Ripper that lists 7z files; as of today, there is not, it's merely listed for the future (indeterminate).

Edited 2016: oclHashcat now supports 7-zip format as well, and is definitely a superior product.

| improve this answer | |
  • 3
    cRARK is your best bet if you have a decent GPU. – quadruplebucky Feb 20 '14 at 9:06
  • 3
    JTR appears to support 7z now – Marc.2377 Jul 12 '17 at 9:52

Not the answer you're looking for? Browse other questions tagged or ask your own question.