QQLan QQlan@yandex.ru reported vulnerability in multiple versions of ICQ 
Inc.'  ICQ instant messenger client in a way it interacts with Microsoft
Internet Explorer.

Author: QQlan  
Title:                  ICQ Client Cross-Application Scripting (XAS)
Vendor:                 ICQ Inc.
Application:            ICQ
Versions:               up to and including 5.04 build 2321
Vulnerability class:    man-in-the-middle, against client
Vulnerability type:     cross application scripting (My Computer zone)
Risk level:             low (high, if unsecured shared network is used)

Intro:

ICQ is probably most popular instant messaging application by ICQ Inc.

Description:

Under some conditions, ICQ client is vulnerable to remote script injection into
My Computer Security Zone of Internet Explorer component used to display
advertisement banners.

Detailed description:

src=http://www.security.nnov.ru/Jdocument327.html> 
Cross  application  scripting  (XAS)  is  possible  when  an application
executes  data in a security context different from the original content
(presumably  one  with less security restrictions). For example the data
may  be obtained from an un-trusted source (a remote web server) that is
sent  unfiltered  into a trusted application such as when web content is
downloaded  from  a  remote  server,  and then re-displayed on the local
host.  Any  application  that  downloads  and  then  later  displays and
executes web content (such as JavaScript) may be vulnerable to XAS.


ICQ Client has very annoying advertising function. Banners are displayed
inside  Internet Explorer COM object embedded into main window, =93Welcome
Screen=94  and  every  =93Message  Session=94  dialogs.  Under  some condition
attacker  can  replace  HTML content in this forms with malicious script
which  will  be  executed  in  My  Computer  security  zone  of Internet
Explorer.

Technical information will be published (three months maybe years later)
after vendor provide a patch.

Workaround:

1. Press Ctrl+Shift+Esc
2. In File/Run menu type cmd.exe
3. In cmd.exe console type
echo 127.0.0.1  ar.atwola.com  >> %SystemRoot%\system32\drivers\etc\hosts

Disclosure timeline:

5/2005 Vulnerability discovered
4/2006 Last attempt to contact vendor
5/2006 Public disclosure

-- 
/3APA3A
http://www.security.nnov.ru/