Advisory

Yorick Koster, September 2019

Authorization bypass in QRadar Forensics web application

Abstract

It was found that any authenticated user can access & use the QRadar Forensics web application, regardless whether they are granted permission to use the Forensics application. This bypass only requires that the user manually sets a cookie named QRIF with the same value as the user's session cookie.

See also

CVE-2020-4274
6189705 - IBM QRadar SIEM is vulenrable to Authorization bypass (CVE-2020-4274)

Tested versions

This issue was successfully verified on QRadar Community Edition version 7.3.1.6 (7.3.1 Build 20180723171558).

Fix

IBM has released the following versions of QRader in which this issue has been resolved:

- QRadar / QRM / QVM / QNI 7.4.0 GA (SFS)
- QRadar / QRM / QVM / QRIF / QNI 7.3.3 Patch 3 (SFS)
- QRadar / QRM / QVM / QRIF / QNI 7.3.2 Patch 7 (SFS)
- QRadar Incident Forensics 7.4.0 (ISO)
- QRadar Incident Forensics 7.4.0 (SFS)

Introduction

QRadar is IBM's enterprise SIEM solution. A free version of QRadar is available that is known as QRadar Community Edition. This version is limited to 50 events per second and 5,000 network flows a minute, supports apps, but is based on a smaller footprint for non-enterprise use.

The QRadar Forensics web application is normally only accessible for users that are granted permission to use this application. A centralized control that checks if the user has permission is implemented in an include file that is included in most pages. This check can be bypassed by sending a QRIF cookie to the application. If this cookie is present and has the same value as the SEC cookie, the permission check is not performed. Consequently, any authenticated user can access & use the Forensics web application.

Details

Most PHP pages of the Forensics application (directly or indirectly) include the PHP file includes/functions.inc.php. A number of checks have been implemented in this file, including a check to validate the user's session, a check to detect Cross-Site Request Forgery attacks, and a permission check to validate if the user has permission to use the Forensics application. This last check is implemented in the LoginUser() method of the QRadarHelper class.

/opt/ibm/forensics/html/DejaVu/qradar_helper.php:
public function LoginUser($sessionToken, &$errorInfo)
{
   global $s, $u, $QR_HELPER_CODES;
[...]
   $qrUserHasForensicsAccess = $this->GetQRuserHasForensics($qr_user_info['username']);

The call to LoginUser() is executed from the LoginCurrentUser() method, which in turn is called form the functions.inc.php include file.

/opt/ibm/forensics/html/includes/functions.inc.php:
require_once('DejaVu/qradar_helper.php');
   
if (!isset($qrh))
{
   $qrh = new QRadarHelper();
   
[...]
   $errorMessage = "";
   $userLoggedIn = $qrh->LoginCurrentUser(true, $errorMessage);

Before the call to LoginUser() is made, the LoginCurrentUser() method first checks if it has received a QRIF cookie. If the cookie is present and it has the same value of the SEC cookie (the session cookie) the call to LoginUser() is not made. Not calling LoginUser() also means that no check is made to validate of the user has permission to use the Forensics application.

/opt/ibm/forensics/html/DejaVu/qradar_helper.php:
public function LoginCurrentUser ($remember, &$errorInfo)
{
[...]
   if(isset($_COOKIE['QRIF']))
   {
      //if the current cookie is the same as the session token that means user hasn't changed
      //just update the expiry time
      if ($_COOKIE['QRIF'] === $this->session_token)
      {
         //if cookie is available that means it hasn't expired yet so we need to update it's expiry time
         //if cookie expiry time is set to 0 (expire with browser) then we don't update it
         if($cookieExpiryTime > 0)
         {
            unset($_COOKIE['QRIF']);
            setcookie("QRIF", $this->session_token, $cookieExpiryTime, "/", $_SERVER['HTTP_HOST'], true, true);
         }
         return true;
      }
      else
      {
         unset($_COOKIE['QRIF']);
      }
   }
   //first time through, login the user and set the cookie
   $loginSuccess = $this->LoginUser($this->session_token, $errorInfo);
   if ($loginSuccess && $remember) {
      setcookie("QRIF", $this->session_token, $cookieExpiryTime, "/", $_SERVER['HTTP_HOST'], true, true);
   }
   return $loginSuccess;
}

By manually setting a QRIF cookie, it is possible for an authenticated user without Forensics permissions to access and use most parts of the Forensics application. It should be noted that after passing the LoginCurrentUser() method, another method is called that checks if the user's session is still valid. Meaning that this bypass effectively only bypasses the Forensics permission check.

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