The first 10 years of the Trojan Horse defence

A trojan is a type of malicious software (globally known as malware) that is either packaged along with a useful piece of software or pretends to be a piece of useful software itself. Once a trojan is activated, which usually goes unnoticed by the user, it releases a payload such as a virus or a backdoor that may allow a remote user to gain access to the system.2,3 A popular means of infection is for online downloads to be packaged with a trojan, resulting in an infection when the user runs the downloaded application. The more complex trojans – those that capture typed keyboard characters or permit a remote user access to the system – can be used to create a credible legal defence. This is in contrast to simple trojans, which act as a nuisance by deleting files and changing user settings. The THD is believed to have been first used in 2003, when it appeared in the Charles Schofield case.4 After a literature review of relevant publications over the past decade, this article discusses court cases where the THD has been used.