A Trojan Horse (named after that of Greek mythology) is a malicious computer program masquerading itself as useful or otherwise non-malicious. Once executed, Trojan Horses often install a backdoor, allowing for remote access of the infected machine. This allows an attacker to perform various criminal tasks including but not limited to: use of the machine as a zombie within a botnet to perform distributed denial-of-service ( DDoS ) attacks, data theft, downloading or installing of additional malware , modification or deletion of files, keylogging, watching the user's screen, crashing the computer, and anonymous internet viewing. They are typically distrubuted vai malspam botnets.
Examples of popular Trojan Horses include: Emotet, Trickbot, Kovter, ZeuS, NanoCore and Redyms