The subject of this department in March was vandalware: malicious programs that replicate themselves and do damage to benign software. The plague of such computer “viruses” and “worms” continues. Rumors of a new virus that attacks spread-sheet programs have been circulating for more than a year, but now they have been confirmed. Virus expert Harold J. Highland, who edits the journal Computers and Security, calls the new infection a macrovirus, because it consists of special commands called macros.

Reports of the macrovirus are difficult to track down, apparently because it has struck corporations that are reluctant to release details to the public. One version of the virus appears to be spreading on Lotus 1-2-3 software. Every time a user runs an infected program, the virus calls up a work sheet from memory at random, alters the numerical content of a single cell by a small amount and puts the altered work sheet back in memory. The damage the virus can do is potentially great, since small changes in data can go unnoticed for months, significantly affecting the results of the spread-sheet calculations.

In spite of such evidence, Tom Pittman of Spreckels, Calif., thinks the March column was an overreaction on my part. According to Pittman, one must be careful to distinguish between useful and destructive viruses. The difference may be semantic. There are certainly useful programs that lead a viral or even wormlike existence. They have jobs that range from file compression to input scanning, but they are not normally called viruses or worms.

Edwin B. Heinlein of Mill Valley, Calif., would press for the establishment of a Center for Computer Disease Control modeled after the Centers for (Human) Disease Control in Atlanta. Such a center would be part of a broader effort for studying and categorizing viruses and for drawing up new laws pertaining to the reporting of incidents and the punishment of offenders. The research undertaken in such an effort might also yield new filters and virus-detection schemes.