How Do Trojans Work?
- A Trojan is a computer virus that is packaged to appear as something benevolent, commonly an antivirus tool, email attachment or instant message. Once the Trojan has entered the computer system, it may then tap into private files to acquire passwords, credit card data and other personal information. Many people don't even know that their computers are infected until performance turns sluggish, with programs suddenly becoming nonresponsive. The more insidious Trojans will even raid address books for contact information, emailing itself under the guise of a familiar message to friends and colleagues. Eventually, the Trojan will cause a catastrophic crash.
- Trojan protection begins with careful web use. Avoid opening email attachments from unfamiliar senders, and always note the file name suffix. Anything mysterious downloaded with an .exe on the end is bad news, and is a program that will damage a computer system. Only download executable files from trusted, known sources.
Be careful when utilizing chat programs such as IRC, AIM or MSN Messenger, or Internet telephony programs like Skype. In the latter, the Warezov Trojan horse infects computers through a chat message that says "Check up this." The link contains an .exe that introduces a Trojan powerful enough to steal address book contacts for self-propagation. - Antivirus and firewall programs do much to combat the spread of a Trojan. A good antivirus setup will catch the offending program before the page can even load, while a firewall will block Internet connections between unauthorized hosts. Since Trojans can hide where the user least expects them, these programs offer the best protection possible for the casual Internet user.
Good shields costs nothing. Several good, free programs with proven track records exist. However, many computer manufacturers and broadband Internet providers supply Norton or McAfee antivirus suites for free. These programs are fast to load, and will keep your computer and network safe from the most common Trojan horse viruses.
