docker-vulnerable-dvwa/dvwa/vulnerabilities/brute/source/impossible.php

<?php

if( isset( $_POST[ 'Login' ] ) && isset ($_POST['username']) && isset ($_POST['password']) ) {
	// Check Anti-CSRF token
	checkToken( $_REQUEST[ 'user_token' ], $_SESSION[ 'session_token' ], 'index.php' );

	// Sanitise username input
	$user = $_POST[ 'username' ];
	$user = stripslashes( $user );
	$user = ((isset($GLOBALS["___mysqli_ston"]) && is_object($GLOBALS["___mysqli_ston"])) ? mysqli_real_escape_string($GLOBALS["___mysqli_ston"],  $user ) : ((trigger_error("[MySQLConverterToo] Fix the mysql_escape_string() call! This code does not work.", E_USER_ERROR)) ? "" : ""));

	// Sanitise password input
	$pass = $_POST[ 'password' ];
	$pass = stripslashes( $pass );
	$pass = ((isset($GLOBALS["___mysqli_ston"]) && is_object($GLOBALS["___mysqli_ston"])) ? mysqli_real_escape_string($GLOBALS["___mysqli_ston"],  $pass ) : ((trigger_error("[MySQLConverterToo] Fix the mysql_escape_string() call! This code does not work.", E_USER_ERROR)) ? "" : ""));
	$pass = md5( $pass );

	// Default values
	$total_failed_login = 3;
	$lockout_time       = 15;
	$account_locked     = false;

	// Check the database (Check user information)
	$data = $db->prepare( 'SELECT failed_login, last_login FROM users WHERE user = (:user) LIMIT 1;' );
	$data->bindParam( ':user', $user, PDO::PARAM_STR );
	$data->execute();
	$row = $data->fetch();

	// Check to see if the user has been locked out.
	if( ( $data->rowCount() == 1 ) && ( $row[ 'failed_login' ] >= $total_failed_login ) )  {
		// User locked out.  Note, using this method would allow for user enumeration!
		//$html .= "<pre><br />This account has been locked due to too many incorrect logins.</pre>";

		// Calculate when the user would be allowed to login again
		$last_login = strtotime( $row[ 'last_login' ] );
		$timeout    = $last_login + ($lockout_time * 60);
		$timenow    = time();

		/*
		print "The last login was: " . date ("h:i:s", $last_login) . "<br />";
		print "The timenow is: " . date ("h:i:s", $timenow) . "<br />";
		print "The timeout is: " . date ("h:i:s", $timeout) . "<br />";
		*/

		// Check to see if enough time has passed, if it hasn't locked the account
		if( $timenow < $timeout ) {
			$account_locked = true;
			// print "The account is locked<br />";
		}
	}

	// Check the database (if username matches the password)
	$data = $db->prepare( 'SELECT * FROM users WHERE user = (:user) AND password = (:password) LIMIT 1;' );
	$data->bindParam( ':user', $user, PDO::PARAM_STR);
	$data->bindParam( ':password', $pass, PDO::PARAM_STR );
	$data->execute();
	$row = $data->fetch();

	// If its a valid login...
	if( ( $data->rowCount() == 1 ) && ( $account_locked == false ) ) {
		// Get users details
		$avatar       = $row[ 'avatar' ];
		$failed_login = $row[ 'failed_login' ];
		$last_login   = $row[ 'last_login' ];

		// Login successful
		$html .= "<p>Welcome to the password protected area <em>{$user}</em></p>";
		$html .= "<img src=\"{$avatar}\" />";

		// Had the account been locked out since last login?
		if( $failed_login >= $total_failed_login ) {
			$html .= "<p><em>Warning</em>: Someone might of been brute forcing your account.</p>";
			$html .= "<p>Number of login attempts: <em>{$failed_login}</em>.<br />Last login attempt was at: <em>${last_login}</em>.</p>";
		}

		// Reset bad login count
		$data = $db->prepare( 'UPDATE users SET failed_login = "0" WHERE user = (:user) LIMIT 1;' );
		$data->bindParam( ':user', $user, PDO::PARAM_STR );
		$data->execute();
	} else {
		// Login failed
		sleep( rand( 2, 4 ) );

		// Give the user some feedback
		$html .= "<pre><br />Username and/or password incorrect.<br /><br/>Alternative, the account has been locked because of too many failed logins.<br />If this is the case, <em>please try again in {$lockout_time} minutes</em>.</pre>";

		// Update bad login count
		$data = $db->prepare( 'UPDATE users SET failed_login = (failed_login + 1) WHERE user = (:user) LIMIT 1;' );
		$data->bindParam( ':user', $user, PDO::PARAM_STR );
		$data->execute();
	}

	// Set the last login time
	$data = $db->prepare( 'UPDATE users SET last_login = now() WHERE user = (:user) LIMIT 1;' );
	$data->bindParam( ':user', $user, PDO::PARAM_STR );
	$data->execute();
}

// Generate Anti-CSRF token
generateSessionToken();

?>