Recently, the most problematic targeted attack in Korea is the Ammyy remote control backdoor being distributed to companies and the Clop ransomware installed through it. The backdoor file was created using the source of the Ammyy remote control program, which is available online, and is planted on the PC being attacked before accessing the system remotely. The malicious file that the attacker wants to finally execute on the system is the Clop ransomware.