CWE-453: Insecure Default Variable Initialization
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Edit Custom FilterThe product, by default, initializes an internal variable with an insecure or less secure value than is possible.
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![]() Languages PHP (Sometimes Prevalent) Class: Not Language-Specific (Undetermined Prevalence) Example 1 This code attempts to login a user using credentials from a POST request: (bad code)
Example Language: PHP
// $user and $pass automatically set from POST request if (login_user($user,$pass)) { $authorized = true; }... if ($authorized) { generatePage(); }Because the $authorized variable is never initialized, PHP will automatically set $authorized to any value included in the POST request if register_globals is enabled. An attacker can send a POST request with an unexpected third value 'authorized' set to 'true' and gain authorized status without supplying valid credentials. Here is a fixed version: (good code)
Example Language: PHP
$user = $_POST['user'];
$pass = $_POST['pass']; $authorized = false; if (login_user($user,$pass)) { $authorized = true; }... This code avoids the issue by initializing the $authorized variable to false and explicitly retrieving the login credentials from the $_POST variable. Regardless, register_globals should never be enabled and is disabled by default in current versions of PHP.
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