Absolute PC Security and Privacy.pdf

Running E-Mail Attachments
The most popular means of transmitting a virus is via e-mail. Virus writers (and sometimes
the virus programs themselves) attach innocent-looking files to e-mail messages, and then
send them out to thousands of users. You receive the e-mail message, along with the
attachments. If you ignore the attachments, no harm is done. But if you open the attachment—
thinking that it’s a picture or a Word document or a text file—you launch an executable
program that contains the virus, and your system gets infected.
You can reduce your risk by not opening file attachments—even if they come from someone
you know. Unfortunately, too many users open any and all attachments without thinking, and
contribute to today’s huge virus infection rates.
Accepting Files While Chatting and Messaging
Exchanging text messages with other users is a relatively safe activity. The activity becomes
dangerous when you start receiving files from the people you talk to, or unsolicited files from
other system users. Download and open one of these files, and you run the risk of infection.
Ignore the file and you stay safe.
The key is to ignore requests to send you files, no matter where they come from, or what they
propose to offer. Maybe it’s a picture of someone you’ve been chatting with in a “personals”
room. Maybe it’s a hot new utility you can use to automate your chat session. It doesn’t
matter. The file might be exactly what it claims to be—or it could be a deadly virus.
It doesn’t even matter if you can see the extension of the file. You know JPG files are safe to
download, so you don’t think twice about accepting the file mypicture.jpg from one of your
chat buddies. But what if a malicious "buddy" actually sent you a file with a name like this
mypicture.jpg
.exe
That’s right, it’s the old double-dot/double-extension spoof, but with a lot of spaces between
the main name and the .exe extension. The filename is so long, in fact, that the extension
doesn’t show in the message window; all you see is the first part of the filename,
mypicture.jpg. Download what you think is a picture file, and you get an infected program file
instead.
The lesson here is that if you accept files when chatting or messaging, you run a very real risk
of your system becoming infected.
Assessing Your Risk Potential
Given the particular way you use your computer, how likely is it that you’ll catch a computer
virus Compare your computer use with the activities listed in Table 2.2 to determine how at
risk you are for a virus infection.
Table 2.2: Virus Risk Potential for Common Computer Activities
Activity Risk Comments
Using commercial Very Low Probably the safest activity you can engage in.