VERY IMPORTANT

The ransomware we’re calling Matrix is another example of what SophosLabs has been observing as a growing trend within the criminal community to engage in active, targeted attacks against victim networks with the goal of delivering malware inside the victim’s network. This threat vector has been gaining prominence since the widely publicized SamSam ransomware began to capitalize on it. The malware is delivered, in most cases, by means of the attackers performing an active brute-force attack against the passwords for Windows machines accessible through a firewall that have the Remote Desktop Protocol (RDP) enabled.