Ontario

Ontario is a family of computer viruses, named after its point of isolation, the Canadian province of Ontario. This family of computer virus consists of Ontario.1024, Ontario.512 and Ontario.2048. The first variant Ontario.512 was discovered in July 1990. Because Ontario.1024 was also discovered in Ontario, it is likely that both viruses originate from within the province. By the Ontario.2048 variant, the author had adopted "Ontario" as the family's name and even included the name "Ontario-3" in the virus code. Ontario.512 Infection Ontario.512 is an encrypting DOS file infector. Upon the execution of an infected .COM, .EXE or .OVL file, Ontario.512 goes memory resident and infects files of these times upon being opened. COMMAND.COM is infected using a special routine. Infected files will increase either 512 bytes (COM files) or between 512 and 1,023 bytes (EXE and OVL files). Some systems with larger file sectors may display increases of greater than 1,023 bytes for infected files of these types. Symptoms Ontario.512 primarily only infects files, so there is no one significant symptom. The two main symptoms are: