September 2006
How to outsmart computer viruses
You might think you're safe opening an e-mail from Microsoft telling you about the latest security threats. But apparently
even Microsoft is not immune to spoofing, which uses e-mail to send virus-spreading messages from a fake site imitating a
real one. The company recently reported that a worm known as the Swen worm was distributed using e-mails emulating a security
bulletin from Microsoft.
Worms and viruses are able to spread widely when malicious software is disguised as innocent-looking e-mail attachments or links. How can you avoid falling victim to tomorrow's computer viruses and worms? Using antivirus, antispyware, and antispam software and updating regularly is essential. If you have a broadband Internet connection, such as cable modem or DSL, always keep an active software or hardware firewall between your computer and the Internet.
But not even security software is foolproof. Add an extra measure of protection by practicing good e-mail hygiene: Never open an attachment or click on a link, no matter how innocent or legitimate it appears, unless you know exactly what it is.
Reviewing the tricks other highly contagious viruses and worms have used can help you fend off future attacks.
Stupid virus tricks: What to look for
Most malevolent software won't infect your machine unless you open an e-mail attachment. So virus distributors use various tricks, which experts call "social engineering," to con you into clicking. A common way to draw you in is to have the e-mail come from a family member or friend.
These illustrations show other basic types of tricks that have been used by well-known viruses and worms. Antidotes were developed for all of them. If you receive messages like these, delete them and run a virus check before doing anything else with the computer.
THE INFECTED DOCUMENT
Here, the subject line includes the name of the sender, probably someone you know. The message itself tempts you to open the attached Microsoft Word document ("don't show to anyone else"). The attachment is a legitimate Word file--but infected with a macro, an invisible, embedded program that runs when Word opens the document.
THE MISLEADING FILE NAME
If you aren't familiar with the way Windows names files, you can easily mistake the attachment's name, "LOVE-LETTER-FOR-YOU.TXT.vbs," for that of a harmless text file. In fact, the file's "vbs" suffix is the real one, which identifies it as a type of program known as a Windows script--a rudimentary computer program that an intruder writes to run on your Windows operating system. The suffix may be hidden entirely on your computer, thus appearing to be a type of file you'd willingly open, such as a JPEG image, MP3 music, or PDF document.
THE OFFER YOU CAN'T REFUSE
This example relies on a message so compelling--an offer to rid your computer of a virus--that it doesn't need to disguise the fact that the attachment is a program. Unfortunately, the program is a worm that sends itself to e-mail addresses it finds on your computer.
THE FAKE WEB LINK
This example uses several tricks. The subject and message suggest that opening the attachment will take you to a web page containing party photos. The attachment's name resembles a web address, but there's no web site involved. This is actually a program that sends itself to your friends and colleagues. This particular intrusion was designed to tie up your e-mail; it could easily have been designed to destroy data.
Worms and viruses are able to spread widely when malicious software is disguised as innocent-looking e-mail attachments or links. How can you avoid falling victim to tomorrow's computer viruses and worms? Using antivirus, antispyware, and antispam software and updating regularly is essential. If you have a broadband Internet connection, such as cable modem or DSL, always keep an active software or hardware firewall between your computer and the Internet.
But not even security software is foolproof. Add an extra measure of protection by practicing good e-mail hygiene: Never open an attachment or click on a link, no matter how innocent or legitimate it appears, unless you know exactly what it is.
Reviewing the tricks other highly contagious viruses and worms have used can help you fend off future attacks.
Stupid virus tricks: What to look for
Most malevolent software won't infect your machine unless you open an e-mail attachment. So virus distributors use various tricks, which experts call "social engineering," to con you into clicking. A common way to draw you in is to have the e-mail come from a family member or friend.
These illustrations show other basic types of tricks that have been used by well-known viruses and worms. Antidotes were developed for all of them. If you receive messages like these, delete them and run a virus check before doing anything else with the computer.
THE INFECTED DOCUMENT
 |
Here, the subject line includes the name of the sender, probably someone you know. The message itself tempts you to open the attached Microsoft Word document ("don't show to anyone else"). The attachment is a legitimate Word file--but infected with a macro, an invisible, embedded program that runs when Word opens the document.
THE MISLEADING FILE NAME
 |
If you aren't familiar with the way Windows names files, you can easily mistake the attachment's name, "LOVE-LETTER-FOR-YOU.TXT.vbs," for that of a harmless text file. In fact, the file's "vbs" suffix is the real one, which identifies it as a type of program known as a Windows script--a rudimentary computer program that an intruder writes to run on your Windows operating system. The suffix may be hidden entirely on your computer, thus appearing to be a type of file you'd willingly open, such as a JPEG image, MP3 music, or PDF document.
THE OFFER YOU CAN'T REFUSE
 |
This example relies on a message so compelling--an offer to rid your computer of a virus--that it doesn't need to disguise the fact that the attachment is a program. Unfortunately, the program is a worm that sends itself to e-mail addresses it finds on your computer.
THE FAKE WEB LINK
 |
This example uses several tricks. The subject and message suggest that opening the attachment will take you to a web page containing party photos. The attachment's name resembles a web address, but there's no web site involved. This is actually a program that sends itself to your friends and colleagues. This particular intrusion was designed to tie up your e-mail; it could easily have been designed to destroy data.
