The Prolock ransomware targets victims with phishing emails, improperly configured Remote Desktop Protocol (RDP) servers, and remote access connections over RDP with stolen user credentials. In some cases, Qakbot was found as one of ProLock’s means of initial access. The earliest detection of ProLock by Sophos was on a customer’s compromised server, most likely through an exploit of a Remote Desktop Protocol connection. The ProLock actors use their access to conduct some network reconnaissance, as well as to potentially steal data before launching their ransomware attack. They then use the stolen or compromised credentials, built-in Windows tools and scripts to propagate the ransomware across the network.