source: http://www.securityfocus.com/bid/2443/info

KICQ is an ICQ-compatible interactive messaging client for Unix. Versions of KICQ are vulnerable to remote execution of arbitrary commands embedded in URLs.

A maliciously-composed URL containing shell metacharacters and shell commands can be sent in an instant message by an attacker.

When the KICQ user clicks this link, the hostile code contained in the URL will execute with the privilege level of the user running KICQ. 

* Attacker composes malicious URL, ie:

http://www.attack.com/index.html'&xterm&'truehttp://www.attack.com </external/http://www.attack.com/index.html'&xterm&'truehttp://www.attack.com>..............................................................

('.' characters = spaces)

* To the target user, the above URL appears to be:

"http://www.attack.com/" </external/http://www.attack.com/>

* When the target user opens the URL, the shell commands contained within it (ie 'xterm') will be executed, potentially without warning to the user.