Bugtraq mailing list archives

Re: IE / Outlook / MS SHLWAPI Render - more trivial crash

From: "Berend-Jan Wever" <SkyLined () edup tudelft nl>
Date: Wed, 23 Apr 2003 14:54:06 +0200

Technical details:

IE tries to compare the type of the input field to "HIDDEN", to see if it
should be rendered. When there is no type string, a null-pointer is used.

mshtml.dll calls shlwapi.dll#158 @ 0x636f0037 with a pointer to a static
unicode string "HIDDEN" and a null-pointer.
shlwapi.dll#158 does a case-insensitive comparison of two unicode strings:
it reads from address 0x0 because of the null-pointer and thus causes an
exception.
This is not exploitable, other then a DoS because there is no memory mapped
@ 0x0 and even if you could load something there, you could only compare it
to "HIDDEN" which gets you nowhere.

Berend-Jan Wever

----- Original Message -----
From: "Gervaize Maquard" <freestyler () tiscali fr>
To: <bugtraq () securityfocus com>
Sent: Tuesday, April 22, 2003 22:29
Subject: RE : IE / Outlook / MS SHLWAPI Render - more trivial crash

Original message :

Hola:
Well, as it seems that is the Microsoft Crash mounth, let see another

one:

---------------------------------
<html>
<form>
<input type crash>
</form>
</html>
---------------------------------
This will crash IE with the following error:
"Unhandled exception in iexplore.exe (SHLWAPI.DLL): 0xC0000005: Access
Violation"
It's a null pointer overwrite, so it's not easly exploitable...

This HTML also crash Outlook, Frontpage, and all the Microsoft programs

that >use the shlwapi.dll library to render web code.

Plain HTML is a dangerous language :)


Added :

It also seems to crash explorer.exe when the .html file containing the
code is copied into any folder !!
It may work since windows is trying to create a view in Windows
explorer. Indeed, it doesn't work when the file is copied in the
desktop.

Tested on Windows XP with Office XP.

Current thread:

IE 6.0 - trivial crash - part II Adam [ckkl] (Apr 19)
- IE / Outlook / MS SHLWAPI Render - more trivial crash Ramon Pinuaga Cascales (Apr 22)
  - RE : IE / Outlook / MS SHLWAPI Render - more trivial crash Gervaize Maquard (Apr 22)
    - Re: IE / Outlook / MS SHLWAPI Render - more trivial crash Berend-Jan Wever (Apr 23)
    - RE: RE : IE / Outlook / MS SHLWAPI Render - more trivial crash kajbaf (Apr 29)