Re: simple password

[olet@ifi.uio.no (Ole J. Tetlie)]

*-Phillip Neumann <filsin@bigfoot.com>
|
| I would like to try security. I have create an account here for user
| `secure'. For the password i have insert a word of 8 word-character. Now, how
| can i login as secure?? How can i guess the password ??

I hope noone flogs me for this, but those already in the know
will gain nothing from this info, and those not will not be
made into crackers just by reading this:

The simplest approach: Get the encrypted password from
/etc/passwd or /etc/shadow. (If you use shadow you shan't be
able to read it without being root - a good thing).
Then you just start generating all combinations of legal
passwords, crypt'ing them and checking against the
encrypted password. You will probably not be able to do
this in a reasonable amount of time if the password is eight
characters, not even with a C program. If you use a password
with for example four characters it shouldn't take much more than
a couple of minutes (rough estimate).

It is also smart (though not in your case) to check for common
things such as dictionary words, words followed by a digit and
such.

Note that if you use shadow passwords, ordinary users can not get
the encrypted password, and will therefore have to try to log in
with each password to try it. This is immensely slower than just
crypting the word and checking against the real encrypted password.

PS: The algoritm used for crypting is oneway only. There is no
way to reverse the function and make it generate the cleartext
from the encrypted word.

PPS: If you want to try this, do it only on your personal
computer. You should also be careful if your computer is
connected to a network.

-- 
Eschew obfuscation    (go on; look them both up)
                                   (Brian White)
olet@ifi.uio.no   [-: .elOle. :-]   olet@debian.org