User accounts have gone missing!

Discussion in 'alt.windows7.general' started by Yousuf Khan, Jul 25, 2010.

  1. Yousuf Khan

    Yousuf Khan Guest

    You've never heard that one before? Never heard of a server before? Not
    very experienced are you?

    Yousuf Khan
     
    Yousuf Khan, Aug 1, 2010
    #21
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  2. Yousuf Khan

    Yousuf Khan Guest

    This thread is already ready for the bit-bucket. I got the answer I
    needed. The rest of this is just name-calling.

    God, who'd have thought there was somebody who made Rod Speed look like
    a gentleman? :)

    Don't reply, the thread will have already have been ignored. :)

    Yousuf Khan
     
    Yousuf Khan, Aug 3, 2010
    #22
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  3. These things make me nervous, since neither the NTFS file system nor the SAM
    file format is documented. I wish they'd just read the file and tell me
    what the password is instead of changing it.
     
    Tom Del Rosso, Aug 8, 2010
    #23
  4. Yousuf Khan

    Sunny Bard Guest

    That would require the password itself to be stored *in* the file, which
    it isn't, and you probably don't want to spend hours/days l0phtcracking
    it ...

    Peter's boot CD/USB is fine, as a get out of jail free card.
     
    Sunny Bard, Aug 8, 2010
    #24
  5. Yousuf Khan

    Bob I Guest

    Some security that would be.
     
    Bob I, Aug 8, 2010
    #25
  6. Yousuf Khan

    Parko Guest

    The password files are encrypted. It's called security.



    --
    Where's the cursor?
    Where's the eraser?
    Where's the cursor?
    Where's the eraser?
    G-O-H-O-H-O-9-O
    G-O-H-O-H-O-9-O
    G-O-H-O-H-O-9-O
    H-O-9-O-G-O-H-O
     
    Parko, Aug 8, 2010
    #26
  7. So it puts the new password somewhere else? Where?
     
    Tom Del Rosso, Aug 21, 2010
    #27
  8. Yousuf Khan

    Rod Speed Guest

    Tom Del Rosso wrote
    Nope, it puts it in the same place, but encryption is a completely different process to decryption.

    In fact when checking whether the password has been entered correctly when say logging
    on, the password entered is encrypted and the encrypted form is compared with the stored
    encrypted form of the original password and if they match, the password is correct. Thats
    nothing like decrypting the stored form of the original password.

    In fact it isnt even possible to reverse some forms of encryption at all, they are one way encryptions.
    Same place the original was stored.
     
    Rod Speed, Aug 21, 2010
    #28
  9. Thanks. That's it then. I'm aware that there are non-reversible
    encryptions, but I didn't consider that possible, because years ago I used
    another password cracker (fee-based, from a commercial operation) to recover
    a password from a Win2k system. It required copying the sam file and
    emailing it to them. I guess they did it by brute force, until they found a
    password that created the same encrypted data. I had always assumed they
    decrypted it.
     
    Tom Del Rosso, Aug 21, 2010
    #29
  10. Yousuf Khan

    Bob I Guest

    FWIW, a similar "cracking" method is used against MS Office documents,
    brute force gets you some character string that provides the same
    "hashcode", it opens the file but most likely wasn't the password
    actually used.
     
    Bob I, Aug 26, 2010
    #30
  11. Yousuf Khan

    Arno Guest

    This is possible, BTW, because the people designing this system
    did not have a clue and selected a too short hashcode.

    The whole thing is derived from Unix password handling (which is
    secure and works), but got broken in the process. No surprise when
    looking at who did this....

    Arno
     
    Arno, Aug 26, 2010
    #31
  12. Yousuf Khan

    David Brown Guest

    Yes, these things are done by trial and error. Often such a company
    will have large "rainbow" tables - they take tables of likely passwords
    (such as common kids names, common pet names, misspellings of
    "password", birthdays, etc.), dictionaries, etc., and run each one
    through the password encryption algorithm. Then "cracking" the password
    is as simple as looking it up in this table. If they get a match, they
    have the original password. If not, then they need to run through
    exhaustive searches.



    If you ever have to break into a windows system again, it is a lot
    easier to use a windows password reset live CD. These don't make any
    attempt to identify the old password, but simply replace it with a known
    (blank) one. It's a lot faster and cheaper than an external company.

    If you actually need to recover the password rather than just change it
    to something you know, there are again free tools for that.
     
    David Brown, Aug 26, 2010
    #32
  13. Yousuf Khan

    Arno Guest

    The accepted countermeasure to Rainbow Tables is salting, i.e.
    to add a non-secret random value. This increses the size of the
    Rainbow Table to infesability. As Microsoft is not familiar with
    salting, they do work there.
    I second that. I did this several times with good success and
    very reasonable effort.
    Whether that works depends strongly on the individual password
    scheme. MS is incompetent here (otherwise breaking would not
    work at all for good passwords), but even they made improvements.

    Here is an example illustratiung the "security mind-set" at Microsoft:
    http://catless.ncl.ac.uk/risks/17.12.html
    Scroll down to ''Microsoft "Bob" passwords''

    Arno
     
    Arno, Aug 26, 2010
    #33
  14. Yousuf Khan

    X00btine

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    You can add a new account agin with some free registry editing programs.
     
    X00btine, Jun 12, 2016
    #34
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