Viruses or Trojan Horses may cause anomalies on individual PCs and throughout the entire network.

  • Viruses can delete files, format disks, and even delete the BIOS from a PC.
  • A Trojan Horse may look like a gift or legitimate product (hence the name), but it hides in the background and picks up logins, passwords, system names, directories, etc.
  • Trojans like Netbus or Back Orifice 2000 may give an attacker complete access to a host or network.
  • ActiveX or JavaScript code from an attacker can cause damage to a host by rebooting the system, taking over the Web browser, or transferring money out of an online banking account.