Mr.

Mr. Smith is a lead incident responder of a small financial enterprise having few

branches in Australia. Recently, the company suffered a massive attack losing USD 5

million through an inter-banking system. After in-depth investigation on the case, it was

found out that the incident occurred because 6 months ago the attackers penetrated the

network through a minor vulnerability and maintained the access without any user

being aware of it. Then, he tried to delete users’ fingerprints and performed a lateral

movement to the computer of a person with privileges in the inter-banking system.

Finally, the attacker gained access and did fraudulent transactions.

Based on the above scenario, identify the most accurate kind of attack.