Indicators of CompromiseAlthough it is commonly thought that adversaries can cleanup after themselves, it is almost impossible to remove all evidence. A good security operations team has the potential to find even the most advanced adversaries. Evidence is always left behind. Indicators of Compromise (IOCs) are artifacts (bits of information) that identify or describe threat actions. An IOC can be anything used to identify
a threat action including, but not limited to:
Unusual
network trafficUnusual user activity
Geographic-specific connections
Increased network traffic
Increased database reads
Unusual file changes or modifications
Registry changes or modifications
Specific
naming or usage conventionsIdentifying actions or action attempts
Signs of DOS/DDOS
Most security organizations rely on some trigger to take action. Systems such as network sensors,
security sensors, or even end-users typically trigger an investigation of "strange" behavior. When a security team responds to a trigger, they are challenged to test their ability
to leverage IOCs to identify, contain, and eradicate a threat. This play between Red and Blue generating and identifying
IOCs is at the heart of Red Teaming. In order to replicate a malicious actor, a Red Team must understand a threat's TTPs. These TTPs are emulated by controlling the "when" and "how, as well as the type of IOC generated or left behind. Given this concept, Red Team Operators must know what indicators are made by a tool or action.
If those IOCs are acceptable, they can proceed. If the IOCs are not acceptable, and the action is performed, there is a significant risk of exposing the Red Team before planned expectations. Not only is the management of an IOC necessary for threat emulation,
but an IOC can get you caught when the timing is not appropriate and may also put an entire engagement at risk if not controlled and managed.
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