An IOC is a piece of evidence or artifact left behind after something has happened. An IOA is a series of actions or behaviors that an adversary employs to achieve his goal. The use of IOCs has been the traditional focus of endpoint detection, but modern adversaries have adapted to more easily evade IOC sweeps. In a forensics investigation, IOCs are the evidence that proves a network’s security has been breached. Unfortunately, by the time the IOC is discovered, the network likely has been compromised. Conversely, IOAs reflect a series of actions the attacker must perform in order to be successful. They are a set of actions that are required for any tool or technique to accomplish common attacker behaviors like code execution, persistence, command and control (C&C), and lateral movement. An effective IOA approach not only collects and analyzes exactly what is happening on the organization’s systems and networks, it does so in real time, preventing the malicious activity from being successful.