<P> Lock - screens, or screen lockers is a type of "cyber police" ransomware that blocks screens on Windows or Android devices with a false accusation in harvesting illegal content, trying to scare the victims into paying up a fee . Jisut and SLocker impact Android devices more than other lock - screens, with Jisut making up nearly 60 percent of all Android ransomware detections . </P> <P> A Trojan horse is a malicious computer program which misrepresents itself to appear useful, routine, or interesting in order to persuade a victim to install it . The term is derived from the Ancient Greek story of the Trojan horse used to invade the city of Troy by stealth . </P> <P> Trojan horses are generally spread by some form of social engineering, for example where a user is duped into executing an e-mail attachment disguised to be unsuspicious, (e.g., a routine form to be filled in), or by drive - by download . Although their payload can be anything, many modern forms act as a backdoor, contacting a controller which can then have unauthorized access to the affected computer . While Trojan horses and backdoors are not easily detectable by themselves, computers may appear to run slower due to heavy processor or network usage . </P> <P> Unlike computer viruses and worms, Trojan horses generally do not attempt to inject themselves into other files or otherwise propagate themselves . </P>

Malware that essentially is a form of social engineering