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Frequently Asked Questions About the Melissa Virus
Last Updated: May 24, 1999
We received reports on May 24, 1999 that the Melissa virus is spreading as RTF files. Files that are true RTF format do not contain macros. Because macros are not in true RTF files anti-virus scanning tools do not scan the files for macro viruses by default. This is being taken advantage of by simply renaming a Word document containing the Melissa macro virus to end in the .RTF extension.
We have first-hand reports of more than 300 organizations affected, covering more than 100,000 individual hosts.
No. Under some circumstances, confidential documents can be leaked without the user's knowledge. These circumstances include the use of a single template file by more than one user, and the transmission of an infected document to another user who has not previously been infected. Additionally, if you fail to clean up the virus correctly and completely (for example, by not cleaning the normal.dot file) you may expose confidential information at a later time.
We have received reports of other variants of Melissa, including one named Papa. At the present time, we have not received a significant number of reports of Papa outbreaks. If you practice antivirus precautions on a regular basis, you can protect yourself against Papa and other variants of Melissa.
No. According to the Department of Energy's Computer Incident Advisory Capability (CIAC), macro viruses for Microsoft Word appeared as early as 1995, with over 1000 variants for Word and other products by 1998. See http://www.ciac.org/ciac/bulletins/i-023.shtml for more information.
Melissa was different from other macro viruses because of the speed at which it spread. The first confirmed reports of Melissa were received on Friday, March 26, 1999. By Monday, March 29, it had reached more than 100,000 computers. Some sites had to take their mail systems off-line. One site reported receiving 32,000 copies of mail messages containing Melissa on their systems within 45 minutes.
No. Macro viruses can affect other products, including other products from Microsoft such as Excel and Powerpoint. The Papa virus, for instance, is reported to be spread via Excel.
Melissa requires user interaction to propagate, therefore we do not consider it a worm. However, Melissa can propagate quickly from one computer to another with minimal interaction required by the user.
The Melissa virus can infect files stored on and shared with MacOS-based systems running Word 98. However, when the virus runs on MacOS systems, it is not able to send electronic mail, and its propagation will be slower on MacOS systems.
At best, marking the normal.dot file read only is a stop-gap protection. On Windows 98/95 systems and on MacOS, viruses can circumvent the read-only protection. Instead, we recommend setting Word to prompt the user before making any changes to the normal.dot file if you are concerned about changes to that file.
Disable macros by default. Use caution when operating any product when macros are enabled. Keep your antivirus products up-to-date. Be leery of unsolicited documents or executable programs received in electronic mail. Beware of software that comes from untrusted sources.
The CERT Coordination Center is a technical organization. We concentrate on the technical aspects of computer security problems. We have no legal authority and we do not "catch the bad guys."
If it is installed, Outlook is used by the virus to send mail. Otherwise, Melissa behaves like a normal virus: you can infect others by carelessly sharing files.
The mailer you use to read mail doesn't matter. The virus will use Outlook, if Outlook is installed, to send copies of itself. How you receive it doesn't matter.
Systems that rely solely on pattern matching to recognize the virus can be used as a stop gap measure to prevent the spread of a particular virus, but will fail as soon as the virus mutates so that it no longer matches the pattern. This can be very effective as a short-term fix, but will not provide long-term protection.
Melissa was relatively non-destructive and easily detected. Variants could be significantly more destructive or stealthy. We strongly encourage you to be aware of the risks posed by viruses and other computer security concerns at all times.
Outlook 98 and Outlook 2000 for Windows platforms can be used to propagate the virus. Microsoft Word 97 and Word 2000 for Windows and Word 98 for Macintosh can be used by the virus to infect other documents. Earlier versions of Word, including Word 95, cannot be used to infect other documents, nor can Outlook Express on any platform be used to propagate the virus via email.
It was named Melissa by the antivirus software vendors.
Yes. To be affected by Melissa and other, similar macro viruses, you must open the attachment and permit macros to run. You cannot be affected by Melissa or similar viruses merely by receiving the email.
Yes. We encourage you to notify them. More information about dealing with incidents can be found in our Incident Reporting Guidelines at
If this option is checked, Word will give you a warning any time you open a document that has macros embedded in it. The warning will give you the opportunity to prevent any macros from running.
No. While Melissa is a macro virus, Happy99.exe is a Trojan horse program. For more information about Happy99.exe, please see Incident Note IN-99-02 Happy99.exe Trojan Horse at
This document is available from: http://www.cert.org/tech_tips/Melissa_FAQ.html
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Copyright 1999 Carnegie Mellon University.