Non-exit on Failed Initialization

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

The following code intends to limit certain operations to the administrator only.

$username = GetCurrentUser();
$state = GetStateData($username);
if (defined($state)) {
  $uid = ExtractUserID($state);
}

# do stuff
if ($uid == 0) {
  DoAdminThings();
}

If the application is unable to extract the state information - say, due to a database timeout - then the $uid variable will not be explicitly set by the programmer. This will cause $uid to be regarded as equivalent to "0" in the conditional, allowing the original user to perform administrator actions. Even if the attacker cannot directly influence the state data, unexpected errors could cause incorrect privileges to be assigned to a user just by accident.

See Also