CODEWITHSUNDEEP
hashhexmd5shadow
Dzsek
Dzsek

Reputation: 33

Hashing a password for unix shadow file

So, I have this entry in a linux shadow file

google.:$1$8KdNUQ4R$ZYyUXVGhvLgVNpfqus.GX/::1:0:1:1:::

The password for this user is com

As I understand the $1$ means it is hashed using md5; 8KdNUQ4R is the salt; and ZYyUXVGhvLgVNpfqus.GX/ is the hashed password itself.

What confuses me is that md5 generators I found online produce a hex value that is 32 characters long, but the hashed password in this case is only 22 chars long, and definitely not a hex.

What steps do I have to go through to get from com to ZYyUXVGhvLgVNpfqus.GX/ using the given salt ?

Edit

So, I found my answer. My problem was that I should have used md5crypt instead of md5.

Upvotes: 3

Views: 2576

Answers (1)

Slava
Slava

Reputation: 44238

If you need to calculate hash for particular password use crypt(3):

#include <iostream>
#include <unistd.h>

int main()
{
   std::cout << crypt( "com", "$1$8KdNUQ4R" ) << std::endl;
   return 0;
}

If you want to know how to get it - result of md5 hash of salt + password is converted to string by base64.

slava@bird:~$ g++ crypt.cpp -lcrypt -o crypt_com
slava@bird:~$ ./crypt_com 
$1$8KdNUQ4R$ZYyUXVGhvLgVNpfqus.GX/

Upvotes: 5

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