Just an additonal note, the people who run
nohack.net (#Nohack on DALnet) have started recommending
this script (direct download) to find and help clean many mIRC-related infections. An AOp of the channel made it and it includes the Matrix2 and script.ini backdoors.
Also, it's best not to place infected URLs in posts, even if you state it's infected - curiosity gets the best of a lot of people, or people may click it before they see your warning simply because of the less "virus like" URL (i.e. it's not a free hosting URL).
Regards,
