On March 2, a message of peace appeared on as many as 350,000 Macintosh computer screens in North America and Europe. The message became the first known contamination of an off-the-shelf program when it cropped up in FreeHand, Aldus Corp’s latest software. The peace virus originally got into many Macs disguised as part of a listing of new Apple products on bulletin boards. As viruses go, this one is pretty harmless – it is simply set to display a message of peace. But the potential for harm, and the fact that it’s now showing up on a major commercial product, has people in a tizzy. Viruses are small, secret programs insidiously inserted into other programs, often as a joke or act of vandalism. They spread from computer to computer as operators share contaminated software. At their most benign, viruses will cause only a message to pop up on a computer screen, as apparently happened here, but at worst they can destroy all the information stored in a computer’s memory or on disk. Richard Brandow of the Canadian computer magazine MacMag told Associated Press that he wrote the virus, but intended only to highlight the dangers of software piracy. Marc Cantor, president of Chicago based MacroMind Inc, is the person accused of letting the virus into copies of Aldus’ drawing program. Cantor created the training disks for Freehand but discovered too late that they had been infected by the MacMag virus. The virus then migrated from the training disk to actual commercial copies of Freehand. Though it was a very benign incident Aldus officials were not amused: We are talking with our attorneys to find out what our legal rights are in this instance, said the Seattle-based company. Aldus also pledged to beef up diskette security and has taken steps to ensure that this doesn’t happen again. The incident shook the industry because Microsoft Corp, Ashton-Tate Corp and Lotus Development Corp are all clients of MacroMind Inc. Ashton-Tate declined to comment, but officials at Microsoft and Lotus said none of their software was infected. In response to the panic caused by the MacMag virus a New Jersey based CD-ROM publishing company, Lasertrieve Inc, has revealed a program which it claims inoculates computers against such viruses. Aimed at large corporate users and software manufacturers the Viralarm program sits on top of a program and uses sophisticated error checking routines to make sure the software has not been tampered with or infected since last used. If the program detects changes, it sends a warning message and will not allow the infected software to run.