The remote web server uses a version of PHP that is affected by a security bypass vulnerability.
Versions of PHP 5.3.x prior to 5.3.7 contains a bug in the crypt() function when generating salted MD5 hashes. The function only returns the salt rather than the salt and hash. Any authentication mechanism that uses crypt() could authorize all authentication attempts due to this bug.
Upgrade to PHP version 5.3.8 or later.