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I have written this Active Directory password changer script. Comments and testing is appreciated for things I may have overlooked, since this is my first AD Script.

There are two parts: PHP and PowerShell.

This is being run on an IIS Server with PHP 5.4.x with Fast CGI and PowerShell 2.x.

The IIS_IUSRS is a manager of a group of all people who can change their own password with this method (as I exclude any account with access to the server).

If IIS_IUSRS is not a manager of a group of people you will get "Access Denied" in the log.

My goal with this script is to change passwords of people that cannot locally access domain computers. While I want this script as secure as possible, limiting those that can change their password and not allowing those with elevated permissions to change password. I was unable to find an escape character function and had to make my own.

Feel free to test this script beyond breaking point and comment, as I would like to see how well I have done in scripting something for Active Directory.

Can anyone confirm that I don't need to escape if possible? Post results if you do break it, please.

Here is the PHP script:

<?php setlocale(LC_CTYPE, "en_US.UTF-8"); ?>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>Pw Changer</title>
<link rel="stylesheet" href="style.css">
</head>
<body>
<?php
/*
* Note: Errorstate var is changeable client side and should not be trusted
*/

$psScriptPath = ".\Bin\Non-Auth\adpwchange2014.ps1";// Path to the PowerShell script.
$logfile = './Logging/Phpruntime.txt';
$date = date('D, d M Y H:i:s');

if(!empty($_GET["successstate"])){//Achievement Get: PW Changer
    echo '<div class="successstate">'. $_GET["successstate"] .'</div>';
    exit(header('refresh:5; ../index.php'));
    }

if(!isset($_POST["submit"])){
    if(!empty($_GET["errorstate"])){echo '<div class="errorstate">' . $_GET["errorstate"] . '</div><br /><br />';}
    // if there was no submit variable passed to the 
    // script (i.e. user has visited the page without clicking submit), display the form:
    echo '<form name="testForm" class="formbox" id="testForm" action="index.php" method="post" />
    Username: <input type="text" name="username" id="username"/><br />
    Old Password: <input type="password" name="old_password"><br />
    New Password: <input type="password" name="new_password"><br />
    Confirm New Password: <input type="password" name="confirm"><br />
    <input type="submit" name="submit" id="submit" value="submit" />
    </form>';

}elseif(!empty($_POST["username"]) && !empty($_POST["old_password"]) && !empty($_POST["new_password"]) && !empty($_POST["confirm"])){// Else if submit was pressed, check if all of the required variables have a value and then Use PHP to check for risks such as Username in password or useing old password
    $errorstate = '';
    if($_POST["new_password"] != $_POST["confirm"]){
        $errorstate .= 'New Password and Confirm do not match</br>';
        }

    $username = utf8_decode($_POST["username"]);
    $old_password = utf8_decode($_POST["old_password"]);
    $new_password = utf8_decode($_POST["new_password"]);
    $confirm = utf8_decode($_POST["confirm"]);

    if(strlen($new_password) <= 8){//Length Check equal or greater then
        $errorstate .= 'Eight or more charictors needed</br>';
        }

    if(strpos($new_password,$old_password) !== false){//New Password Matches username or old password
        $errorstate .= 'Can not contain your old password</br>';
        }

    if(strpos($new_password, $username) !== false){
        $errorstate .= 'Can not contain your Username</br>';
        }

    $operator = array('\\','#','+','<','>',';','\"','=',',');//Operators that need to be escaped with
    $replace = array('\\\\','\\#','\\+','\\<','\\>','\\;','\\"','\\=','\,');//replacement

    $username = str_replace ($operator, $replace, $username);
    #$new_password = str_replace ($operator, $replace, $new_password);
    #$old_password = str_replace ($operator, $replace, $old_password);

    $check_upper = 0;
    $check_lower = 0;
    $check_digit = 0;
    $check_punct = 0;

    foreach(count_chars($new_password, 1) as $key => $value){//Strength Test Results can be derived from $value
        if(!ctype_upper(chr($key))){$check_upper=1;}//if Upper-case
        if(!ctype_lower(chr($key))){$check_lower=1;}//if Lower-case
        if(!ctype_digit(chr($key))){$check_digit=1;}//if Numeric
        if(!ctype_punct(chr($key))){$check_punct=1;}//if Symbol
        if($check_upper + $check_lower + $check_digit + $check_punct>= 3){}//Save us from checking the entire string
        }

    if($check_upper + $check_lower + $check_digit + $check_punct<= 2){
        $errorstate .= 'Password needs to contain at least 3 of the following criteria: Upper-case, Lower-case, Numeric and/or Symbol</br>';
        }

    if(!empty($errorstate)){//EXIT if error state is set. Do not pass go, do not collect $200.
        exit(header('Location: .?errorstate='.$errorstate));
        }

    $user = $username;
    $username = base64_encode($username); //Transport Layer Base64
    $new_password = base64_encode($new_password); //Transport Layer Base64
    $old_password = base64_encode($old_password); //Transport Layer Base64

    /*
    * The danger happens here as it is sent to powershell.
    */
    $query = shell_exec('powershell.exe -ExecutionPolicy ByPass -command "' . $psScriptPath . '" < NUL -base64_username "' . $username . '" < NUL -base64_oldpassword "' . $old_password . '" < NUL -base64_newpassword "' . $new_password . '" < NUL');// Execute the PowerShell script, passing the parameters
    /*
    *Log the query result
    */

    if(stristr($query, 'Success:') !== false){ //Return True
        $logstr = '========================================'."\r\n";
        $logstr .= '    ' . $date . ' - Success'."\r\n";
        $logstr .= '========================================'."\r\n";
        $logstr .= $_SERVER['REMOTE_ADDR'] . ' - ' . $user .": Attempted Password Change result \r\n";
        $logstr .= $query . "\r\n";
        $logstr .= "\r\n";
        file_put_contents($logfile, $logstr, FILE_APPEND | LOCK_EX);
        $errorstate = '</br>Success: Password was changed</br>';
        exit(header('Location: ./index.php?successstate='.$errorstate));

    }elseif(stristr($query, 'Failed:') !== false){ //Return False
        $logstr = '========================================'."\r\n";
        $logstr .= '    ' . $date . ' - Failed'."\r\n";
        $logstr .= '========================================'."\r\n";
        $logstr .= $_SERVER['REMOTE_ADDR'] . ' - ' . $user .": Attempted Password Change result \r\n";
        $logstr .= $query . "\r\n";
        $logstr .= "\r\n";
        file_put_contents($logfile, $logstr, FILE_APPEND | LOCK_EX);
        $errorstate = '</br>Failed: Password was not changed</br>';
        exit(header('Location: .?errorstate='.$errorstate));

    }else{//someone broke something not that we tell them but we log the entry
        $logstr = '========================================'."\r\n";
        $logstr .= '            ' . $date . ' - Error Warning'."\r\n";
        $logstr .= '========================================'."\r\n";
        $logstr .= $_SERVER['REMOTE_ADDR'] . ' - ' . $user .": Attempted Password Change result \r\n";
        $logstr .= 'powershell.exe -ExecutionPolicy ByPass -command "' . $psScriptPath . '" < NUL -username "' . $username . '" < NUL -oldpassword "' . $old_password . '" < NUL -newpassword "' . $new_password . '" < NUL' . "\r\n";
        $logstr .= $query . "\r\n";
        $logstr .= 'Username: ' .$username . "\r\n";
        $logstr .= 'Old Password: ' .$old_password . "\r\n";
        $logstr .= 'New Password: ' .$new_password . "\r\n";
        $logstr .= "\r\n";
        file_put_contents($logfile, $logstr, FILE_APPEND | LOCK_EX);
        //You could go one step further and ban IP for X time // you could also send an email to yourself
        $errorstate = '</br>Failed: Password was not changed</br>';
        exit(header('Location: .?errorstate='.$errorstate));
        }

}else{// Else the user hit submit without all required fields being filled out:
    $errorstate = 'Please Complete all fields</br>';
    exit(header('Location: .?errorstate='.$errorstate));
    }
?>

</body>
</html>

And here is the PowerShell:

#*=============================================================================
#* Script Name: adpwchange2014.ps1
#* Created: 2014-10-07
#* Author:
#* Purpose: This is a simple script that queries AD users.
#* Reference Website: http://theboywonder.co.uk/2012/07/29/executing-powershell-using-php-and-iis/
#* 
#*=============================================================================

#*=============================================================================
#* PARAMETER DECLARATION
#*=============================================================================
param(
[string]$base64_username,
[string]$base64_newpassword,
[string]$base64_oldpassword
)

#*=============================================================================
#* IMPORT LIBRARIES
#*=============================================================================

if ((Get-Module | where {$_.Name -match "ActiveDirectory"}) -eq $null)
{
#Loading module
Write-Host "Loading module AcitveDirectory..."
Import-Module ActiveDirectory
}
#*=============================================================================
#* PARAMETERS
#*=============================================================================
$username = [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($base64_username))
$newpassword = [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($base64_newpassword))
$oldpassword = [System.Text.Encoding]::UTF8.GetString([System.Convert]::FromBase64String($base64_oldpassword))

#*=============================================================================
#* INITIALISE VARIABLES
#*=============================================================================
# Increase buffer width/height to avoid PowerShell from wrapping the text before
# sending it back to PHP (this results in weird spaces).
$pshost = Get-Host
$pswindow = $pshost.ui.rawui
$newsize = $pswindow.buffersize
$newsize.height = 1000
$newsize.width = 300
$pswindow.buffersize = $newsize

#*=============================================================================
#* EXCEPTION HANDLER
#*=============================================================================

#*=============================================================================
#* FUNCTION LISTINGS
#*=============================================================================

    Function Test-ADAuthentication  {
        Param($Auth_User, $Auth_Pass)
        $domain = $env:USERDOMAIN

        Add-Type -AssemblyName System.DirectoryServices.AccountManagement
        $ct = [System.DirectoryServices.AccountManagement.ContextType]::Domain
        $pc = New-Object System.DirectoryServices.AccountManagement.PrincipalContext($ct, $domain)
        $pc.ValidateCredentials($Auth_User, $Auth_Pass).ToString()
        }

    Function Set-ADAuthentication{
        Param($Auth_User,$Auth_OldPass, $Auth_NewPass)
        $domain = $env:USERDOMAIN
        $Auth_NewPass = ConvertTo-SecureString $Auth_NewPass -AsPlainText -Force
        $Auth_OldPass = ConvertTo-SecureString $Auth_OldPass -AsPlainText -Force
        #Running -whatif to simulate results
        #Therefore we expect "Failed: Password change" as it was not changed
        Set-ADAccountPassword -Identity $Auth_User -NewPassword $Auth_NewPass -OldPassword $Auth_OldPass -PassThru
        $authentication = Test-ADAuthentication $username $newpassword
        if ($authentication -eq $TRUE) {
            Write-Output "Success: Password Changed"
            }elseif ($authentication -eq $FALSE) {
            Write-Output "Failed: Password Change"
            }else {
                Write-Output "Error: EOS"
                EXIT
                NUL
                Stop-Process -processname powershell*
                }
        }

#*=============================================================================
#* Function: function1
#* Purpose: This function does X Y Z
#* =============================================================================

#*=============================================================================
#* END OF FUNCTION LISTINGS
#*=============================================================================

#*=============================================================================
#* SCRIPT BODY
#*=============================================================================
Write-Output $PSVersionTable
Write-Output "  "
$authentication = Test-ADAuthentication "$username" "$oldpassword"
if ($authentication -eq $TRUE) {
    Set-ADAuthentication $username $oldpassword $newpassword
    }elseif ($authentication -eq $FALSE) {
    Write-Output "Failed: Validation"
    }else {Write-Output "Error: EOS"
    EXIT
    NUL
    Stop-Process -processname powershell*
    }

#*=============================================================================
#* SCRIPT Exit
#*=============================================================================
EXIT
NUL
Stop-Process -processname powershell*
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  • \$\begingroup\$ I had to resort to making this piece because i couldn't find anything like it before. Exchange use to provide such a service but stopped when Windows server 2008 came out unfortunately. And i hope i get constructive criticism so i can improve. \$\endgroup\$ – Werezwolf Nov 20 '14 at 2:06
  • \$\begingroup\$ Perhaps the escapeshellarg function is worth a look \$\endgroup\$ – Elias Van Ootegem Nov 20 '14 at 12:41
  • \$\begingroup\$ Ive tryed that but its suited to command line and not AD thus leaves artifacts in passwords. Thus not helpfull in computer enviroments \$\endgroup\$ – Werezwolf Nov 20 '14 at 12:57
  • \$\begingroup\$ Rewrote had a small problem that wasent returning properly - also made it live this will change the password. \$\endgroup\$ – Werezwolf Nov 21 '14 at 3:51
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I don't really know anything about powershell, so I will only look at your PHP script.

XSS

echo '<div class="successstate">'. $_GET["successstate"] .'</div>';

This is vulnerable to reflected XSS, with which an attacker could execute arbitrary Javascript on a victims computer (and thus steal cookies, deface the website, display a phishing form, etc). Use htmlspecialchars to prevent this (same with errorstate).

Functions

Your code isn't all that long, but for 150 lines, I would extract some code to functions to structure it. For example, displayPasswordChangeForm and processPasswordChangeForm, and checkPasswordStrength.

I would also add a logQueryResult function to avoid duplicate code:

function logQueryResult($queryString, $date, $result, $redirect, $additional) {
    $logstr = '========================================'."\r\n";
    $logstr .= '    ' . $date . ' - ' . $result . ."\r\n";
    $logstr .= '========================================'."\r\n";
    $logstr .= $_SERVER['REMOTE_ADDR'] . ' - ' . $user .": Attempted Password Change result \r\n";
    $logstr .= $query . "\r\n";
    $logstr .= $additional;
    $logstr .= "\r\n";
    file_put_contents($logfile, $logstr, FILE_APPEND | LOCK_EX);
    $errorstate = '</br>' . $result . ': Password was changed</br>';
    exit(header('Location: ' $redirect));
}

// use like this:
logQueryResult($query, $date, 'Success', './index.php?successstate='.$errorstate, '');
logQueryResult($query, $date, 'Failed', '.?errorstate='.$errorstate, '');

$plainUserPass = 'Username: ' .$username . "\r\n";
$plainUserPass .= 'Old Password: ' .$old_password . "\r\n";
$plainUserPass .= 'New Password: ' .$new_password . "\r\n";
logQueryResult($query, $date, 'Error Warning', '.?errorstate='.$errorstate, $plainUserPass);

Misc

  • when building a string, either use all double or all single quote. Code Like $var = 'foo' . $test . "'bar'" . '\n' for example is hard to read.
  • always close your curly brackets at the same time (I would close it where the opening line began, it's easier to see which block it closes that way).
  • personally, I would use more spaces (before {, after } and ,, around ., etc.)
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  • \$\begingroup\$ I think I'll have to find another method of displaying the results nicely to the user. The log query Result I am working on to make it into a function is a hard one because the result comes from the query string and I don't think date is a necessary item because its basically when it happens. I'll update the changes based on your recommendation thank you. \$\endgroup\$ – Werezwolf Nov 24 '14 at 22:35
  • \$\begingroup\$ I'm not sure making functions would help with this as its all to do with sanitizing for Active Directory i barely repeat something more then twice. But i did manage to compress my logging thanks to your recommendation. And i should of fixed the XSS with Session values. \$\endgroup\$ – Werezwolf Nov 25 '14 at 2:18

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