Mean Time to Detect Explained: MTTD, MTTR, MTBF and MTTF for CySA+
Mean time to detect (MTTD) is the average time between a security incident beginning and the organization noticing it. It is one of the few security metrics that maps directly onto damage, because almost everything an attacker achieves happens during that window. Every hour an intrusion goes undetected is an hour the attacker spends moving laterally, escalating privileges, and locating your data. The uncomfortable truth behind the metric is that industry-wide dwell times have historically been measured in weeks and months rather than hours. They have improved markedly — partly through better tooling, and partly because ransomware announces itself, which drags the average down for reasons nobody should celebrate. The Family of Metrics MTTD sits in a sequence, and exams test the whole set together. Metric Measures Clock starts Clock stops MTTD — mean time to detect Detection speed Incident begins Someone notices MTTA — mean time to acknowledge Triage responsiveness Alert ...