E-Mail

E-mail provides quick and easy means to communicate with others. It also provides attackers a quick and easy means to put a malicious application on your computer. E-mail has become a necessity for many people, however by having an e-mail account your computer and information are put at risk. By following some basic guidelines you can better protect yourself from viruses, worms, and other malicious applications spread through e-mail.

Some basic guidelines to follow for safe e-mail use are:

• Do not open unsolicited e-mail from people or e-mail addresses you do not know.
• Do not open file attachments to unsolicited e-mail from people you do know without first confirming the e-mail is authentic.
• Disable the preview pane.
• Install anti-virus software and keep it up to date.

File Attachments

The most common means used to deliver a malicious application is as a file attachment. Often the e-mail will contain a message stating that the attached file is some new game, interesting pictures, or an entertaining story. In reality the attached file is a virus which, once opened, will infect your computer and then copy itself and send it to every e-mail address within the your contact list, putting those people at risk as well.

If you do not know the sender of an e-mail then do not open any attachments to that e-mail.

Malicious applications spread through e-mail will often use fake return e-mail addresses. E-mail from an unknown address should be treated with caution.

Some malicious applications will steal the contact list of the victim's e-mail account and then copy itself to those e-mail addresses. This can result in e-mails from addresses you know to contain malicious applications.

If you receive an unsolicited e-mail from a person you know do not open it until you first confirm it came from the person who sent it.

Some approaches to determining if a file attachment may be opened included looking at the filename extension and the icon associated with the file. (The filename extension is the three letters after the period at the end of a file's name.) These approaches are not recommended as it is possible to hide a filename's real extension and to insert a false icon into a file. These tricks are known to attackers and easy to implement.

Filename extension and icon should not be relied upon to determine the validity of a file attachment.

Window To Problems

Not all malicious applications that spread through e-mail appear as file attachments. Some viruses and worms have been designed to exploit bugs in how certain e-mail clients display the content of an e-mail. It is possible that just by viewing the contents of an e-mail a malicious application may be launched. To protect against this type of attack it's best to not open any e-mails that come from unknown sources.

Disable the preview pane to prevent accidental viewing of e-mails that may have embedded instructions to launch a malicious program.

One feature common among e-mail clients is what's called the preview pane The preview pane is where the contents of an e-mail is displayed as soon as it is selected from a list of e-mails. The problem with the preview pane is that to delete an e-mail requires that it first be selected and that when selected, the e-mail's contents will be displayed. If an e-mail contains an embedded instruction to launch a malicious application and it is selected to be deleted, the malicious application will be launched before it gets deleted.

Be Prepared

Determining which e-mails could be malicious is a guessing game at best. It is inevitable that a malicious program will slip through. The best defense at that point is good anti-virus software that is up to date. Virus and worm outbreaks occur most often within the first few days of being "in the wild". This makes it incredibly important to keep anti-virus software up to date. Anti-virus software that is even a few weeks out-of-date could miss the latest virus or worm as it spreads across the internet and into vulnerable computers

Many anti-virus applications include auto-update features which will download the latest updates to the software as they become available. If you already employ anti-virus software check with the software's documentation on how to enable the auto-update feature.

Bridgewater State College offers free anti-virus software to all faculty, staff and students. The software includes an auto-update to help keep the software current and your computer secure. If not already installed, it is recommended all BSC faculty, staff and students download and install this software on their personal computers. Computers provided by the college already contain anti-virus software and do not need this software to be installed.

Last Modified: May 7, 2008