Working with purple team for improvement¶
A blue team in isolation builds defences against the threats it can imagine. Purple teaming gives it the chance to test those defences against techniques chosen by people who think differently, and to learn from the gaps that the testing reveals.
Before purple team exercises¶
Success criteria are defined before the engagement. Which detections are expected to fire? Which response procedures need to execute? What is the expected timeline? Without explicit criteria, the post-exercise reflection becomes a discussion of impressions rather than evidence.
Current capabilities are baselined. What monitoring exists, what alerts are configured, what response playbooks are ready, what is known to work and what has not been tested. The baseline is the reference point against which the exercise findings are interpreted.
Focus areas are identified. A new EDR deployment, an updated detection rule, a recently revised response procedure, each is a candidate for targeted testing. Naming the focus areas before the exercise produces sharper findings than running a generic engagement and seeing what comes up.
During purple team exercises¶
Real-time monitoring watches for alerts, detections, and anomalies as the red team operates. What triggered, what did not, and the timing of each, are documented as they happen.
Operational tempo continues. Pausing normal defensive work for the exercise produces unrealistic conditions; the exercise tests how detection and response work alongside the rest of the daily work, not in place of it.
Observations get communicated. What is being detected, or not, is shared with the purple team facilitator so the red team can adjust pace or tactics if the exercise has stopped producing useful information.
Response procedures are practised, not simulated. When detection fires, the actual procedure runs, with the same handoffs and escalations that would happen in a real incident. Practising the procedure under realistic conditions is what makes it work when an actual incident arrives.
After purple team exercises¶
Gap analysis compares the expected detections against what actually fired. Blind spots, missed alerts, and delayed detections become the priority list.
Detection engineering builds new rules, tunes existing alerts, and improves correlation logic based on the red team’s TTPs. The detail captured during the exercise is what makes this work specific rather than generic.
Playbook updates refine incident response procedures based on the exercise: missing steps added, roles clarified, communication channels improved.
Tool effectiveness is assessed against actual adversary behaviour. Did EDR catch malware? Did SIEM correlate events? Did deception technology work? Validating security investments against real evidence is more useful than relying on vendor claims.
A prioritised improvement backlog comes out of the engagement, with clear owners and timelines, tracked to completion before the next exercise.