The correct answer isObservation of repeated failed logins followed by a successful login from a new location. This scenario represents anIndicator of Attack (IOA)because it reflectsattacker behavior in progress, not confirmed compromise.
IOAs focus onpatterns of malicious intent, such as credential abuse, reconnaissance, or lateral movement, even when no malware or known indicators are present. In this case, the sequence of failed authentication attempts followed by a successful login from an unusual location strongly suggestspassword spraying or credential stuffing, both common initial access techniques.
Options A, B, and D are classicIndicators of Compromise (IOCs). Hashes, domains, and IP addresses are static artifacts that indicate a systemhas already been compromised. These indicators sit low on thePyramid of Painand are easy for attackers to change.
Cisco’sCBRTHD blueprintemphasizes hunting forIOAsbecause they enable:
Earlier detection
Reduced dwell time
Higher attacker cost
Cisco tools such asSecure Network Analytics,Secure Endpoint, and SIEM platforms are designed to correlate behavioral signals like authentication anomalies rather than relying solely on known bad indicators.
Therefore,Option Cis the correct and Cisco-aligned answer.
