Re: Trillian Remote DoS

From: Erik Jacobson (uhlumeat_private)
Date: Tue Jul 08 2003 - 05:19:18 PDT

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Maybe in reply to: flur: "Trillian Remote DoS"
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Did you even bother notifying the vendor?  Or crediting the person who 
originally discovered this?  Unless you happen to be him, although it 
doesn't appear so from your site.

Anyway, this bug has been known about for a while, and is fixed in the next 
version.  Unfortunately they aren't releasing a patch before then.

----Original Message Follows----
From: flur <flurat_private>
To: bugtraq Security List <bugtraqat_private>
Subject: Trillian Remote DoS
Date: Fri, 04 Jul 2003 18:09:55 -0400

Application:    Trillian
Developer(s):   Cerulean Studios (http://www.trillian.cc)
Scope:          Remote DoS & Possible Exploit
Tested on:      Trillian 1.0 Pro, 0.74 Freeware

It is possible to crash Trillian by sending a corrupt 'TypingUser' message. 
Replacing any of the characters in 'TypingUser' will cause Trillian to 
crash. If more then 10 characters are used, or if the colon is omitted, 
Trillian will not crash. The crash occurs due to a function within msn.dll 
for both Trillian 1 and 0.74. This may be exploitable further.

In order to exploit this condition, no code is necessary- simply hex edit a  
messenger client, replacing the string 'TypingUser' with any other string of 
the same length (or simply changing a letter or two). However this method of 
exploitation does break Microsoft's EULA/TOS, and you are not encouraged to 
utilize a broken client in this way except in an educational context. This 
'hack' also prevents other non-trillian Messenger clients from detecting 
when a user is typing.

Crash Summary:

MOV ECX,DWORD PTR DS:[EDX]  ; EDX is uninitialized

The crash looks something like this:

Instruction at 0x####8826 referenced memory at 0x00000000

Sample TCP session to crash Trillian:

MIME-Version: 1.0
Content-Type: text/x-msmsgscontrol
TypingXxxx: attackerat_private

Our preliminary tests showed that memory was not manipulable, and thus this 
bug is not exploitable further then DoS. Please make further research public 
if you discover otherwise.

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Next message: XNUXER RESEARCH: "WDAV exploit without netcat and with pretty magic number"
Previous message: Paul Szabo: "Re: [Full-Disclosure] Re: [sec-labs] Adobe Acrobat Reader <=5.0.7 Buffer Overflow Vulnerability + PoC code"
Maybe in reply to: flur: "Trillian Remote DoS"
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