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Hello Folks
am a linux admisnistrator "Root", one of my users lost his password and i want to get it back , am using fedora core 3 how can that be done ... am waiting for any kind of help
The second field of /etc/shadow is the encrypted password of the user. If you have a recent backup you can add that password back by getting it out of the old /etc/shadow and pasting it into the current one.
The second field of /etc/shadow is the encrypted password of the user. If you have a recent backup you can add that password back by getting it out of the old /etc/shadow and pasting it into the current one.
Good point---I never backup stuff in /etc so this obvious option did not make it into my brain....
Linux passwords are stored using a one-way encryption system. Whenever the password is typed in, it is encrypted into an encoded format. To verify a user's login, the system just compares the encrypted forms.
There is no reverse algorithm for the encryption. If you want to find out the user's password, then the only way to do it is to try every possible combination until you find a match. If it was possible to easily reverse-engineer the password from its encrypted form, then securing the password would be much harder.
The second field of /etc/shadow is the encrypted password of the user. If you have a recent backup you can add that password back by getting it out of the old /etc/shadow and pasting it into the current one.
But that does not help if the user has lost his/her password......
No, there isn't. A password cracker can't generate the password from the hash. It generates its own hash from its own password and compares the result with the original hash. The direction of the operation isn't reversed at any point.
No, there isn't. A password cracker can't generate the password from the hash. It generates its own hash from its own password and compares the result with the original hash. The direction of the operation isn't reversed at any point.
Exactly. And almost always, that IS the original password. The link I gave shows a good example of that where the user password was "fred123". The ripper found exactly that quickly.
That IS a reversal. A brute force reversal, but a reversal none the less.
That IS a reversal. A brute force reversal, but a reversal none the less.
Any type of password cracking which uses guessing (this includes both brute force and dictionary) is NOT doing anything in reverse. It's the exact same operation which was done when the original password hash was originally created, the difference being that you're doing it a gazillion times and the resulting hash of each guess is compared to see if it matches the original one. It's not reversal, the direction remains the same. You're just doing tons of comparison.
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