Unverified Password Change

Description

This could be used by an attacker to change passwords for another user, thus gaining the privileges associated with that user.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

This code changes a user's password.

$user = $_GET['user'];
$pass = $_GET['pass'];
$checkpass = $_GET['checkpass'];
if ($pass == $checkpass) {
  SetUserPassword($user, $pass);
}

While the code confirms that the requesting user typed the same new password twice, it does not confirm that the user requesting the password change is the same user whose password will be changed. An attacker can request a change of another user's password and gain control of the victim's account.

See Also