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: attacker@blah.com
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.
____________________ __ _ ~FluRDoInG flur@flurnet.org http://www.flurnet.org KEY ID 0x8C2C37C4 (pgp.mit.edu) RSA-CAST 2048/2048 1876 B762 F909 91EB 0C02 C06B 83FF E6C5 8C2C 37C4
