A trojan virus is a small program that runs hidden on an infected computer. The trojan gives hackers access to get stored passwords from your computer, read your personal documents, delete files and break your computer, display pictures, and/or show messages on your screen.
How did I get infected?
Trojans are executable programs, which means that when you open the file, it will perform some action(s). In Windows, executable programs have file extensions like “exe”, “vbs”, “com”, “bat”, etc. Some actual trojan filenames include: “dmsetup.exe” and “LOVE-LETTER-FOR-YOU.TXT.vbs” (when there are multiple extensions, only the last one counts, be sure to unhide your extension so that you see it).
Trojans can be spread in the guise of literally ANYTHING people find desirable, such as a free game, movie, song, etc. Victims typically downloaded the trojan from a WWW or FTP archive, got it via peer to peer file exchange using IRC/instant messaging/Kazaa etc., or just carelessly opened some email attachment. Trojans usually do their damage silently. The first sign of trouble is often when others tell you that you are attacking them or trying to infect them!
How do I avoid getting infected in the future?
You must be certain of BOTH the source AND content of each file you download! In other words, you need to be sure that you trust not only the person or file server that gave you the file, but also the contents of the file itself.
Here are some practical tips to avoid getting infected:
• NEVER download blindly from people or sites which you aren’t 100% sure about. In other words, as the old saying goes, don’t accept candy from strangers. If you do a lot of file downloading, it’s often just a matter of time before you fall victim to a trojan.
• Even if the file comes from a friend, you still must be sure what the file is before opening it, because many trojans will automatically try to spread themselves to friends in an email address book or on an IRC channel. There is seldom reason for a friend to send you a file that you didn’t ask for. When in doubt, ask them first, and scan the attachment with a fully updated anti-virus program.
• Beware of hidden file extensions! Windows by default hides the last extension of a file, so that innocuous-looking “susie.jpg” might really be “susie.jpg.exe” – an executable trojan! To reduce the chances of being tricked, unhide those pesky extensions.
• NEVER use features in your programs that automatically get or preview files. Those features may seem convenient, but they let anybody send you anything which is extremely reckless. For example, never turn on “auto DCC get” in mIRC, instead ALWAYS screen every single file you get manually. Likewise, disable the preview mode in Outlook and other email programs.
• Never blindly type commands that others tell you to type, or go to web addresses mentioned by strangers, or run pre-fabricated programs or scripts (not even popular ones). If you do so, you are potentially trusting a stranger with control over your computer, which can lead to trojan infection or other serious harm.
• Don’t be lured into a false sense of security just because you run anti-virus programs. Those do not protect perfectly against many viruses and trojans, even when fully up to date. Anti-virus programs should not be your front line of security, but instead they serve as a backup in case something sneaks onto your computer.
How do I get rid of trojans?
Here are your many options, none of them are perfect. I strongly suggest you read through all of them before rushing out and trying to run some program blindly. Remember – that’s how you got in this trouble in the first place. Good luck!
Clean Re-installation: Although arduous, this will always be the only sure way to eradicate a trojan or virus. Back up your entire hard disk, reformat the disk, re-install the operating system and all your applications from original CDs, and finally, if you’re certain they are not infected, restore your user files from the backup. If you are not up to the task, you can pay for a professional repair service to do it.
Anti-Virus Software: Some of these can handle most of the well known trojans, but none are perfect, no matter what their advertising claims. You absolutely MUST make sure you have the very latest update files for your programs, or else they will miss the latest trojans. Compared to traditional viruses, today’s trojans evolve much quicker and come in many seemingly innocuous forms, so anti-virus software is always going to be playing catch up. Also, if they fail to find every trojan, anti-virus software can give you a false sense of security, such that you go about your business not realizing that you are still dangerously compromised. There are many products to choose from, but the following are generally effective: AVP,PC-cillin, and McAfee VirusScan. All are available for immediate downloading typically with a 30 day free trial. Anti-Trojan Programs: These programs specialize in trojans instead of general viruses. For the same reasons, some of these programs are effective against most trojans, but none of them will ever be effective against all trojans.