The Cybercriminal’s Toolkits 225
A worm can corrupt documents frequently used by users, businesses,
and governments on all hard drives connected to an infected PC. It can even
affect external data storage devices. Worms are propagated through e-mails –
often when attached to messages attracting recipients with subject lines such
as “hot movie” or “Crazy Illegal sex.” Once the recipient opens the attach-
ment, a program disabling the anti-virus software can be launched. The mali-
cious code may not necessarily aim to install backdoor or keystroke loggers.
Instead, it may simply aim to destroy all important les on the computer. In
order to accomplish this feat, the worm injects le deletion instructions onto
servers.
A Trojan horse presents ...