Changes have been made in CVS for this ticket:

More salt improvements - use all base64 characters (not just hex) for crypt,
crypt-des, and crypt-blowfish (Bug #8425).


http://git.horde.org/diff.php/framework/Auth/lib/Horde/Auth.php?rt=horde-git&r1=4ef82a9d67556dda442771964a32ce5d8a6a581d&r2=7a49e649d831346749ac5ddb0a8e4ef16f11d414

More salt improvements - use all base64 characters (not just hex) for crypt,
crypt-des, and crypt-blowfish (Bug #8425).

Added changes for crypt, crypt-des, and crypt-blowfish also. Thanks!

Committed the crypt-md5 change:

http://git.horde.org/diff.php/framework/Auth/lib/Horde/Auth.php?rt=horde-git&r1=83ba16e6c0ec3c989eab0a81fcda06978ddef8a1&r2=e57680006a7a0c33f08a94e05ebf7c69b486d401

A similar thing should be fine -

substr(base64_encode(hash('md5', mt_rand(), true)), 0, 2) for example. 
(It would be best to not use a MD5 at all and just use the random 
numbers directly, but I'm not sure how to do that.) I don't know what 
the salt requirements for crypt-blowfish are.

Also crypt-blowfish

I think the code has changed a bit in the latest version. I've got 
this for the crypt-md5 case:



diff --git a/framework/Auth/lib/Horde/Auth.php 
b/framework/Auth/lib/Horde/Auth.php

index 8a5695a..fce7771 100644

--- a/framework/Auth/lib/Horde/Auth.php

+++ b/framework/Auth/lib/Horde/Auth.php

@@ -266,7 +266,7 @@ class Horde_Auth

          case 'crypt-md5':

              return $seed

                  ? substr(preg_replace('|^{crypt}|i', '', $seed), 0, 12)

-                : '$1$' . substr(hash('md5', mt_rand()), 0, 8) . '$';

+                : '$1$' . base64_encode(hash('md5', 
sprintf('%08X%08X', mt_rand(), mt_rand()), true)) . '$';



          case 'crypt-blowfish':

              return $seed



What would you suggest for crypt and crypt-des? It's currently:



         case 'crypt':

         case 'crypt-des':

             return $seed

                 ? substr(preg_replace('|^{crypt}|i', '', $seed), 0, 2)

                 : substr(hash('md5', mt_rand()), 0, 2);



Thanks!

In lib/Horde/Auth.php, the function getSalt uses a poor algorithm for 
generating salts for crypt-*. crypt allows, at the very least, all 
Base64 characters in the salt, but the current algorithm only 
generates hexadecimal digits. Furthermore, for crypt-md5, 8 bytes of 
salt is permitted, so there are 64^8 = 2^48 possible salt values (if 
we only allow Base64 characters), but on most systems, mt_rand() only 
generates 2^31 different values, so the current algorithm generates at 
most 2^31 different salt values.



A better algorithm would use, for example, 
base64_encode(md5(sprintf('%08X%08X', mt_rand(), mt_rand()), TRUE)) 
instead of just md5(mt_rand()).