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Division of IT: Security
Viruses and Patches
So what exactly is a computer virus? Simply put, a virus is a piece of software that piggybacks onto legitimate programs. Every time the legitimate program runs, the virus also runs.
There are three primary kinds of viruses:
- A Trojan horse is a computer program that claims to do one thing but instead does damage when you run it.
- A worm (or wormable virus) is a small piece of computer software that replicates itself by targeting security holes in other programs. Once the worm is activated on one machine, it scans the network for other machines with the same security vulnerabilities. Once it finds one, it copies itself to the new computer. Then, the replication process starts again. Worms can spread very quickly — for example, the recent Mydoom worm is estimated to have infected a quarter million computers in a single day.
- An e-mail virus is simply a kind of virus that is spread via e-mail messages. Usually, these viruses replicate by automatically sending themselves to people in the infected machine's address book (often without the user's knowledge). For example, the ILOVEYOU virus which appeared on May 4, 2000 contained an attachment that, when clicked on, executed a code that sent copies of the virus to everyone in the victim's address book. One of the most common ways of virus transmittal is via e-mail attachments. Even if the e-mail appears to come from someone you know, you should still be cautious — e-mail addresses can be spoofed, or the sender could have unwittingly sent you a virus.
To protect against viruses of all types, keep your system updated with the latest patches and .
Microsoft Updates
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