1. Advertising
    y u no do it?

    Advertising (learn more)

    Advertise virtually anything here, with CPM banner ads, CPM email ads and CPC contextual links. You can target relevant areas of the site and show ads based on geographical location of the user if you wish.

    Starts at just $1 per CPM or $0.10 per CPC.

Hacking a password-protected .zip file

Discussion in 'Programming' started by AHA7, Dec 15, 2007.

  1. #1
    Hello,

    I have a password-protected .zip file which I've lost its password during a system crash (the password was stored in a text file).
    The problem is that the password (as I do remember) was a random alphanumeric string with a length of 10+ chars (can't really be exact on this but I'm pretty sure it's 10+), so a brute password hack may take months :(

    Is there any efficient way I can crack this password?
     
    AHA7, Dec 15, 2007 IP
  2. ARonald

    ARonald Peon

    Messages:
    909
    Likes Received:
    35
    Best Answers:
    0
    Trophy Points:
    0
    #2
    I do not see any option other than bruteforce. But you could go the other way round and recover the txt file containing the password using a data recovery tool. That would be much easier than cracking a password. Do backup files regularly as it helps in data disasters.
     
    ARonald, Dec 15, 2007 IP
  3. AHA7

    AHA7 Peon

    Messages:
    445
    Likes Received:
    5
    Best Answers:
    0
    Trophy Points:
    0
    #3
    Thanks for the tip but I couldn't recover that file as (apparently) it got overwritten when new OS was installed.

    As to brute force hacks: what do you know about the rate (speed) of the best free brute force cracker software?
     
    AHA7, Dec 15, 2007 IP
  4. AstarothSolutions

    AstarothSolutions Peon

    Messages:
    2,682
    Likes Received:
    77
    Best Answers:
    0
    Trophy Points:
    0
    #4
    given that it is random there wont be much difference in speed of programs and the speed of your PC will be the key
     
    AstarothSolutions, Dec 15, 2007 IP
  5. theone2003a

    theone2003a Member

    Messages:
    45
    Likes Received:
    1
    Best Answers:
    0
    Trophy Points:
    43
    #5
    Just Brute Force it (Takes average a month or so)
     
    theone2003a, Dec 15, 2007 IP
  6. joebert

    joebert Well-Known Member

    Messages:
    2,152
    Likes Received:
    88
    Best Answers:
    0
    Trophy Points:
    145
    #6
    The password has to be stored in the file somewhere. If it wasn't then how would the reader know you're entering a valid password ?

    If you're going to do somthing, figure out where that somewhere is & work on that.
     
    joebert, Dec 15, 2007 IP
  7. AHA7

    AHA7 Peon

    Messages:
    445
    Likes Received:
    5
    Best Answers:
    0
    Trophy Points:
    0
    #7
    But won't it be one-way encrypted?
     
    AHA7, Dec 15, 2007 IP
  8. joebert

    joebert Well-Known Member

    Messages:
    2,152
    Likes Received:
    88
    Best Answers:
    0
    Trophy Points:
    145
    #8
    I don't know. :)
     
    joebert, Dec 15, 2007 IP
  9. Barti1987

    Barti1987 Well-Known Member

    Messages:
    2,617
    Likes Received:
    101
    Best Answers:
    0
    Trophy Points:
    105
    #9
    The only way is brute force.

    How long it takes depending on how long the actual password is.

    If the password length is 5 characters, then you are looking at 94 factorial limit 5: 6,586,922,160 tries.

    Peace,
     
    Barti1987, Dec 15, 2007 IP
  10. picobello

    picobello Active Member

    Messages:
    572
    Likes Received:
    17
    Best Answers:
    0
    Trophy Points:
    60
    #10
    The brute force attack does support full parallelism in this case so, if you can use 10 computers you will divide the total time by 10.
     
    picobello, Dec 16, 2007 IP
  11. Kaizoku

    Kaizoku Well-Known Member

    Messages:
    1,261
    Likes Received:
    20
    Best Answers:
    1
    Trophy Points:
    105
    #11
    There is a program called ollydbg, you can use it reverse-engineer the zip file.
     
    Kaizoku, Dec 16, 2007 IP
  12. aliasx

    aliasx Guest

    Messages:
    258
    Likes Received:
    3
    Best Answers:
    0
    Trophy Points:
    0
    #12
    I'm trying to crack a .zip to which I forgot the password.. I know some specs though, pretty sure it was under 8 char. I'm using fcrackzip under linux and ultimate zip cracker on windows. Time consuming, yes. But worth it.
     
    aliasx, Dec 17, 2007 IP