The Pentacrest on the campus of the University of Iowa. (Stephen Mally/The Gazette) The Gazette offers audio versions of articles using Instaread. Some words may be mispronounced. A Trojan Horse is computer malware disguised as a harmless file: when opened it takes over your system, perhaps to steal your financial information. An antivirus Trojan Horse is designed to make you think your computer is infected with a virus, so you’ll panic and click on the file.