PHP Australia Conference 2015

crack_check

(PECL crack >= 0.1)

crack_checkPerforms an obscure check with the given password

Description

bool crack_check ( resource $dictionary , string $password )
bool crack_check ( string $password )

Performs an obscure check with the given password on the specified dictionary.

Warning

This function is EXPERIMENTAL. The behaviour of this function, its name, and surrounding documentation may change without notice in a future release of PHP. This function should be used at your own risk.

Parameters

dictionary

The crack lib dictionary. If not specified, the last opened dictionary is used.

password

The tested password.

Return Values

Returns TRUE if password is strong, or FALSE otherwise.

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User Contributed Notes 2 notes

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Anonymous
4 years ago
In addition to the usual checks crack can also check for similarities between the password and a username and gecos field (the gecos field normally contains the person's full name on unix systems).

There is a third format for the function call which supplies these additional parameters:

bool crack_check (string $password, string $username, string $gecos, resource $dictionary)

This is true of PECL crack version 0.4, I'm not sure about earlier versions.
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-1
vkontakte at mralston dot com
4 years ago
If you need to test a password with cracklib but don't have the necessary module available in PHP, you can use a function like this.
It requires the command line cracklib-check binary in /usr/sbin, but changing its location is trivial.
The $message variable will contain cracklib's complaint (if there is one)
You'll want to wrap your invocation of this function in a try...catch block.

<?php
function cracklibCheck($password, &$message)
{
   
// Clean up password
   
$password=str_replace("\r", "", $password);
   
$password=str_replace("\n", "", $password);

   
// Run password through cracklib-check
   
exec("echo ".escapeshellarg($password)." | /usr/sbin/cracklib-check 2>/dev/null", $output, $return_var);
   
   
// Check it ran properly
   
if($return_var==0)
    {
        if(
preg_match("/^.*\: ([^:]+)$/", $output[0], $matches))
        {
           
// Check response
           
if(strtoupper($matches[1])=="OK")
            {
               
// Password is strong
               
$message="";
                return(
true);
            }
            else
            {
               
// Cracklib doesn't like it
               
$message=$matches[1];
                return(
false);
            }
        }
        else
        {
           
// Badly formatted response from cracklib-check.
           
throw new Exception("Didn't understand cracklib-check response.");
        }
    }
    else
    {
       
// Some sort of execution error
       
throw new Exception("Failed to run cracklib-check.");
    }
}
?>
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