Indicators of compromise
There are many events that would take place on a busy network. Events can be recorded in logs (where an event is unusual) or coupled with another event that itself appears unusual. This could be an indicator of compromise (IOC). Another example of an IOC could be several unsuccessful attempts to connect using SSH to a core network appliance, followed by a successful authentication attempt from an unusual or gray-listed IP address. It is important for the security operation center to be able to identify attacks or threats. To identify IOCs, we need inputs in the form of logs and captured network traffic.
Packet capture
Packet capture (PCAP) files use a standard log format. They allow us to capture real-time data. Captured data can be analyzed using Wireshark, tcpdump, or tshark. See Wireshark capture in Figure 5.7:
The PCAP format allows logs to be analyzed using different vendor tools and platforms...