Late in 2004, viruses took a turn for the worse, intensifying interest in network and host security. The Scob Trojan (aka Download.ject) and the various Sasser（Figure 1） worm variants are more sophisticated than previous viruses, while Scob's payload is especially dangerous.

《圖一: Sasser worm infected》

Outbreaks of the Scob Trojan（Figure 2） have serious implications for both businesses and individuals. Scob is a keystroke logger that records whatever the user types into his or her computer, and sends it over the Internet to a hacker. Information such as an online banking login, user name and password, PIN (Personal Identification Number), even a network login name and password are no longer secure and confidential.

《圖二: Scob Trojan locates the System folder and copies itself to that location.》

Such keystroke loggers have disturbing implications for businesses. When banking data gets compromised and customers lose money through these malicious attacks, who bears the liability? If the infected PC or laptop was operating behind a company firewall, should the company bear part of the blame - and the liability?
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