Molly IRC bot 0.5 allows remote attackers to execute arbitrary commands via shell metacharacters in (1) the $host variable for nslookup.pl, (2) the $to, $from, or $message variables in pop.pl, (3) the $words or $text variables in sms.pl, or (4) the $server or $printer variables in hpled.pl.
http://www.securityfocus.com/bid/6007
http://www.iss.net/security_center/static/10397.php
http://online.securityfocus.com/archive/1/296163
http://archives.neohapsis.com/archives/vulnwatch/2002-q4/0028.html