During a red team simulation at a bank in Chicago, Illinois, the SOC team suspects...

Packet Filtering

TCP Flow Control Method

IP Identification Number (IPID) Monitoring

Direct TTL Probes

BThe analyst is using the TCP Flow Control Method because the scenario focuses on monitoring TCP sequence values for irregularities. In TCP communications, sequence (and acknowledgment) numbers are fundamental to flow control and reliability. A legitimate TCP stream follows predictable rules: sequence numbers progress according to the amount of data transmitted, acknowledgments align with received bytes, and the relationship between seq/ack values is consistent for each direction of the session. When traffic is spoofed—especially if an attacker injects packets without fully participating in the legitimate TCP state—those packets often contain sequence numbers that do not match the expected window for the established connection. This can create anomalies such as out-of-window sequence values, incorrect acknowledgments, or resets triggered by the endpoints.By monitoring sequence-related behavior, defenders can spot signs of forged or injected packets that were not produced by the true endpoint. This technique is particularly relevant when dealing with suspected TCP session spoofing or injection, where attackers attempt to insert data or disrupt sessions by guessing or stealing sequence numbers.Why the other options don’t match the “sequence values” clue:Packet Filtering (A) is a preventive control (blocking by rules), not a detection method based on analyzing sequence progression.IPID Monitoring (C) focuses on the IP Identification field behavior patterns to infer spoofing (often OS-specific IPID increments), but the scenario is clearly about TCP sequence values, not IP header ID patterns.Direct TTL Probes (D) examine TTL characteristics (hop count anomalies) to infer spoofing or path differences; again, not sequence-number analysis.Therefore, the spoofing detection technique described is B. TCP Flow Control Method.