app/functions_external.php
<?php

/*

bWAPP, or a buggy web application, is a free and open source deliberately insecure web application.
It helps security enthusiasts, developers and students to discover and to prevent web vulnerabilities.
bWAPP covers all major known web vulnerabilities, including all risks from the OWASP Top 10 project!
It is for security-testing and educational purposes only.

Enjoy!

Malik Mesellem
Twitter: @MME_IT

bWAPP is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (http://creativecommons.org/licenses/by-nc-nd/4.0/). Copyright © 2014 MME BVBA. All rights reserved.

*/

function no_check($data)
{    
   
    return $data;
        
}

function email_check_1($data)
{
    
    return preg_match("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$^", $data);
    
}

function email_check_2($data)
{
    
    return filter_var($data, FILTER_VALIDATE_EMAIL);  
     
}

function maili_check_1($data)
{

    // URL decoding %0A -> \n and %0D -> \r
    $input = urldecode($data); 
        
    $input = str_replace("\n", "", $input);
    $input = str_replace("\r", "", $input);
    $input = str_replace("bcc:", "", $input);
    
    return $input;
    
}

function maili_check_2($data)
{

    // URL decoding %0A -> \n and %0D -> \r
    $input = urldecode($data);
    
    $input = filter_var($input, FILTER_SANITIZE_EMAIL);
            
    return $input;
    
}

function url_check_1($data)
{

    // URL decoding %0A -> \n and %0D -> \r
    $input = urldecode($data);
    
    $input = filter_var($input, FILTER_SANITIZE_URL);
            
    return $input;
    
}

function url_check_2($data)
{

    // URL encoding
    $input = urlencode($data);  
            
    return $input;
    
}

function xss_check_1($data)
{
    
    // Converts only "<" and ">" to HTLM entities    
    $input = str_replace("<", "&lt;", $data);
    $input = str_replace(">", "&gt;", $input);
    
    // Failure is an option
    // Bypasses double encoding attacks   
    // <script>alert(0)</script>
    // %3Cscript%3Ealert%280%29%3C%2Fscript%3E
    // %253Cscript%253Ealert%25280%2529%253C%252Fscript%253E
    $input = urldecode($input);
    
    return $input;
    
}

function xss_check_2($data)
{
  
    // htmlentities - converts all applicable characters to HTML entities
    
    return htmlentities($data, ENT_QUOTES);
    
}

function xss_check_3($data, $encoding = "UTF-8")
{

    // htmlspecialchars - converts special characters to HTML entities    
    // '&' (ampersand) becomes '&amp;' 
    // '"' (double quote) becomes '&quot;' when ENT_NOQUOTES is not set
    // "'" (single quote) becomes '&#039;' (or &apos;) only when ENT_QUOTES is set
    // '<' (less than) becomes '&lt;'
    // '>' (greater than) becomes '&gt;'  
    
    return htmlspecialchars($data, ENT_QUOTES, $encoding);
       
}

function xss_check_4($data)
{
  
    // addslashes - returns a string with backslashes before characters that need to be quoted in database queries etc.
    // These characters are single quote ('), double quote ("), backslash (\) and NUL (the NULL byte).
    // Do NOT use this for XSS or HTML validations!!!
    
    return addslashes($data);
    
}

function xmli_check_1($data)
{

    // Replaces dangerous characters: ( ) = ' [ ] : , * / WHITESPACE
    $input = str_replace("(", "", $data);
    $input = str_replace(")", "", $input);
    $input = str_replace("=", "", $input);
    $input = str_replace("'", "", $input);
    $input = str_replace("[", "", $input);
    $input = str_replace("]", "", $input);
    $input = str_replace(":", "", $input);
    $input = str_replace(",", "", $input);
    $input = str_replace("*", "", $input);
    $input = str_replace("/", "", $input);
    $input = str_replace(" ", "", $input);
   
    return $input;
    
}

function ldapi_check_1($data)
{

    // Replaces dangerous characters: ( ) = & | * WHITESPACE
    $input = str_replace("(", "", $data);
    $input = str_replace(")", "", $input);
    $input = str_replace("=", "", $input);
    $input = str_replace("&", "", $input);
    $input = str_replace("|", "", $input);
    $input = str_replace("*", "", $input);
    $input = str_replace(" ", "", $input);
   
    return $input;
    
}

function commandi_check_1($data)
{
    
    $input = str_replace("&", "", $data);
    $input = str_replace(";", "", $input);
    
    return $input;
    
}

function commandi_check_2($data)
{
   
    return escapeshellcmd($data);
    
}

function commandi_check_3($data)
{
    
    $input = str_replace("&", "", $data);
    $input = str_replace(";", "", $input);
    $input = str_replace("|", "", $input);
    
    return $input;
    
}

function sqli_check_1($data)
{
   
    return addslashes($data);
    
}

function sqli_check_2($data)
{
   
    return mysql_real_escape_string($data);
    
}

function sqli_check_3($link, $data)
{
   
    return mysqli_real_escape_string($link, $data);
    
}

function sqli_check_4($data)
{

    // Not bulletproof
    
    // Replaces a single quote (')
    $input = str_replace("'", "''", $data);
   
    return $input;
    
}

function file_upload_check_1($file, $file_extensions  = array("asp", "aspx", "dll", "exe", "jsp", "php"), $directory = "images")
{
    
    $file_error = "";
    
    // Checks if the input field is empty
    if($file["name"] == "")
    {
        
        $file_error = "Please select a file...";
        
        return $file_error;
        
    }
    
    // Checks if there is an error with the file
    switch($file["error"])
    
    // URL: http://php.net/manual/en/features.file-upload.errors.php
    
    {
        
        case 1 : $file_error = "Sorry, the file is too large. Please try again...";
                 break;
             
        case 2 : $file_error = "Sorry, the file is too large. Please try again...";
                 break;
             
        case 3 : $file_error = "Sorry, the file was only partially uploaded. Please try again...";
                 break;
             
        case 6 : $file_error = "Sorry, a temporary folder is missing. Please try again...";
                 break;
             
        case 7 : $file_error = "Sorry, the file could not be written. Please try again...";
                 break;
             
        case 8 : $file_error = "Sorry, a PHP extension stopped the file upload. Please try again...";
                 break;
             
    }
    
    if($file_error)
    {
        
        return $file_error;
        
    }
    
    // Breaks the file in pieces (.) All pieces are put in an array
    $file_array = explode(".", $file["name"]);
    
    // Puts the last part of the array (= the file extension) in a new variabele
    // Converts the characters to lower case
    $file_extension = strtolower($file_array[count($file_array) - 1]);
    
    // Searches if the file extension exists in the 'allowed' file extensions array   
    if(in_array($file_extension, $file_extensions))
    {
        
       $file_error = "Sorry, the file extension is not allowed. The following extensions are blocked: <b>" . join(", ", $file_extensions) . "</b>";
       
       return $file_error;
       
    }
    
    // Checks if the file already exists in the directory
    if(is_file("$directory/" . $file["name"]))
    {
        
        $file_error = "Sorry, the file already exists. Please rename the file...";      
        
    }
    
    return $file_error;
    
}

function file_upload_check_2($file, $file_extensions  = array("jpeg", "jpg", "png", "gif"), $directory = "images")
{
    
    $file_error = "";
    
    // Checks if the input field is empty
    if($file["name"] == "")
    {
        
        $file_error = "Please select a file...";
        
        return $file_error;
        
    }
    
    // Checks if there is an error with the file
    switch($file["error"])
    
    // URL: http://php.net/manual/en/features.file-upload.errors.php
    
    {
        
        case 1 : $file_error = "Sorry, the file is too large. Please try again...";
                 break;
             
        case 2 : $file_error = "Sorry, the file is too large. Please try again...";
                 break;
             
        case 3 : $file_error = "Sorry, the file was only partially uploaded. Please try again...";
                 break;
             
        case 6 : $file_error = "Sorry, a temporary folder is missing. Please try again...";
                 break;
             
        case 7 : $file_error = "Sorry, the file could not be written. Please try again...";
                 break;
             
        case 8 : $file_error = "Sorry, a PHP extension stopped the file upload. Please try again...";
                 break;
             
    }
    
    if($file_error)
    {
        
        return $file_error;
        
    }
    
    // Breaks the file in pieces (.) All pieces are put in an array
    $file_array = explode(".", $file["name"]);
    
    // Puts the last part of the array (= the file extension) in a new variabele
    // Converts the characters to lower case
    $file_extension = strtolower($file_array[count($file_array) - 1]);
    
    // Searches if the file extension exists in the 'allowed' file extensions array   
    if(!in_array($file_extension, $file_extensions))
    {
        
       $file_error = "Sorry, the file extension is not allowed. Only the following extensions are allowed: <b>" . join(", ", $file_extensions) . "</b>";
       
       return $file_error;
       
    }
    
    // Checks if the file already exists in the directory
    if(is_file("$directory/" . $file["name"]))
    {
        
        $file_error = "Sorry, the file already exists. Please rename the file...";      
        
    }
    
    return $file_error;
    
}

function directory_traversal_check_1($data)
{

    // Not bulletproof
    
    $directory_traversal_error = "";  
    
    // Searches for special characters in the GET parameter
    if(strpos($data, "../") !== false ||
       strpos($data, "..\\") !== false ||
       strpos($data, "/..") !== false ||
       strpos($data, "\..") !== false)
            
    {

        $directory_traversal_error = "Directory Traversal detected!";
    
    }
    
    /*
    else
    {
    
        echo "Good path!";
    
    }     
     */
    
    return $directory_traversal_error;

}

function directory_traversal_check_2($data)
{

    // Not bulletproof
    
    $directory_traversal_error = "";  
    
    // Searches for special characters in the GET parameter
    if(strpos($data, "../") !== false ||
       strpos($data, "..\\") !== false ||
       strpos($data, "/..") !== false ||
       strpos($data, "\..") !== false ||
       strpos($data, ".") !== false)
            
    {

        $directory_traversal_error = "Directory Traversal detected!";
    
    }
    
    /*
    else
    {
    
        echo "Good path!";
    
    }     
     */
    
    return $directory_traversal_error;

}

function directory_traversal_check_3($user_path,$base_path = "")
{
    
    $directory_traversal_error = "";
    
    $real_base_path = realpath($base_path);

    // echo "base path: " . $base_path . " real base path: " . $real_base_path . "<br />";

    $real_user_path = realpath($user_path);

    // echo "user path: " . $user_path . " real user path: " . $real_user_path . "<br />";

    // int strpos ( string $haystack , mixed $needle [, int $offset = 0 ] )
    // URL: http://php.net/manual/en/function.strpos.php
    if(strpos($real_user_path, $real_base_path) === false)
    {
    
        $directory_traversal_error = "<font color=\"red\">An error occurred, please try again.</font>";
    
    }

    /*
    else
    {
    
        echo "Good path!";
    
    }     
     */
    
    return $directory_traversal_error;

}

// Detects multiple parameters with same name (HTTP Parameter Pollution)
function hpp_check_1($data)
{

    // Debug
    // echo $data;
   
    $query_string  = explode("&", $data);    

    $i = "";
    $param = array();
    $param_variables = array();

    foreach($query_string as $i)
    {

            $param = explode("=", $i);
            array_push($param_variables, $param[0]);

    }

    $count_unique = count(array_unique($param_variables));
    $count_total = count($param_variables);
    
    $hpp_detected = "";

    // $hpp_detected = ($count_unique < $count_total);
    // echo $hpp_detected;
    
    if($count_unique < $count_total)
    {

        $hpp_detected = "<font color=\"red\">HTTP Parameter Pollution detected!</font>";

    }

    return $hpp_detected;

}

function rlfi_check_1($data)
{

    // Replaces the null-byte character
    $input = str_replace(chr(0), "", $data);

    // Replaces directory traversal characters
    $input = str_replace("../", "", $input);
    $input = str_replace("..\\", "", $input);
    $input = str_replace("/..", "", $input);
    $input = str_replace("\..", "", $input);

    return $input;

}

function random_string()
{
    
    $character_set_array = array();
    
    $character_set_array[] = array("count" => 3, "characters" => "abcdefghijklmnopqrstuvwxyz");
    $character_set_array[] = array("count" => 1, "characters" => "ABCDEFGHIJKLMNOPQRSTUVWXYZ");
    $character_set_array[] = array("count" => 1, "characters" => "0123456789");
    // $character_set_array[] = array("count" => 1, "characters" => "!@#$+-*&?:");
    $character_set_array[] = array("count" => 1, "characters" => "@#$+-?!");
    
    $temp_array = array();
    
    foreach($character_set_array as $character_set)
    {
        
        for($i=0; $i<$character_set["count"]; $i++)
        {
            
            $temp_array[] = $character_set["characters"][rand(0, strlen($character_set["characters"]) - 1)];
            
        }
        
    }
    
    shuffle($temp_array);
    
    return implode('', $temp_array);
}

// Returns the textual SID
function bin_sid_to_text($binsid)
{
    
    $hex_sid = bin2hex($binsid);
    $rev = hexdec(substr($hex_sid, 0, 2));// Gets the revision-part of the SID
    $subcount = hexdec(substr($hex_sid, 2, 2));// Gets count of sub-auth entries
    $auth = hexdec(substr($hex_sid, 4, 12));// SECURITY_NT_AUTHORITY
    $result = "$rev-$auth";
    
    // Retrieves the full SID
    /*
    for($x=0; $x<$subcount; $x++)
    {

        $subauth[$x] = hexdec(little_endian(substr($hex_sid, 16+($x*8), 8)));  // Gets all SECURITY_NT_AUTHORITY
        $result.= "-" . $subauth[$x];

    }
    */ 
    
    // Retrieves only the last part of the SID = '$subcount-1'
    $result = hexdec(little_endian(substr($hex_sid, 16+(($subcount-1)*8), 8)));
        
    return $result;
     
}
 
// Converts a little-endian hex-number to one, that 'hexdec' can convert
function little_endian($hex)
{
     
    for($x = strlen($hex)-2; $x>=0; $x=$x-2)
    {

        $result.= substr($hex, $x, 2);

    }

    return $result;

}

?>