The most important thing you can do to protect yourself from computer viruses is to make sure you have up-to-date antivirus software running on your computer. Use this software to scan every file you receive from any source, including friends, family, and co-workers! Cornell provides all students, faculty, and staff with Symantec Anti-Virus (also known as Norton Anti-Virus). Please visit our Norton Anti-Virus page for complete details.

Eudora for Macintosh does not have most of the vulnerabilities of certain Windows e-mail clients. It provides at least partial protection against the two main methods e-mail viruses attack: HTML code and attachments.

Executables in HTML

It's possible to embed code in HTML that will cause your computer to run a program when the HTML code is displayed. While Eudora uses HTML code in incoming e-mail to display styled text, it does not allow executable programs within HTML. It uses its own rendering engine (unlike the Windows version of Eudora, which can optionally use the Microsoft web-page viewer built into Windows).

Attachments

Of more concern is the possibility that a virus might travel in a file that's attached to an e-mail message. That's how most of the recent viruses in the news have gotten around. In general, if you aren't sure what a file is, don't open it without checking with the sender. The old warning about only opening files sent by people you know doesn't help, since most of the recent viruses send themselves as messages that seem to come from someone you know.

All attached files received by one of Cornell's newer e-mail servers are automatically scanned for all known viruses using PureMessage. If your full email address includes "postofficeX.mail.cornell.edu" (where "X" is 6, 7, 8, 9, or 10) then your attachments are being checked; some units have their own mail servers; check with your technical support provider if you are unsure.

The two main types of troublesome files are applications or scripts that contain viruses, or documents (especially Word and Excel documents) that contain malicious macros.

Eudora provides an extra level of protection against applications that might contain malicious code. When you receive an application or other executable (such as an AppleScript) by mail, Eudora leaves it in a "packed" state. If you try to open the program, Eudora warns you that you are about to run a program, and says, "If you are sure it is a legitimate copy, I will unpack it and launch it." This makes sure you're aware that you're about to open (and run) a program, and not a document. Only if you are absolutely certain that the program is legitimate should you allow Eudora to launch it directly. A safer approach is to let Eudora unpack the program first, and you can then scan it with Norton Antivirus.

Word and Excel documents are susceptible to macro viruses, which take advantage of Microsoft's macro feature, which allows documents to contain programming scripts. Users who don't use these features in Word and Excel can safely turn them off. Even so, it's a good idea to scan incoming files using your antivirus software to be on the safe side.