Key takeaways
- A purple team day is one loop repeated per technique: execute, compare what each side saw, record a verdict, tune, re-run. Plan the day around how many times that loop can close, not around how many techniques can be executed.
- Four roles have to be in the room. Without write access to the detection platform, every miss becomes a ticket instead of a rule.
- Record three verdicts: it alerted, it was logged and nothing fired, or it was never collected. The second is detection engineering and often closes the same day; the third is a platform work item with a lead time.
- Re-run each new rule against a varied procedure before calling it a pass. A rule keyed on the operator's binary name is a signature for one afternoon.
- What leaves the room is rule content in your own syntax and version control, the verdict record, the tuning notes, the collection work items and the entries the day did not reach.
A purple team day is one loop, repeated
A purple team session is not a demonstration followed by a report. It is one loop, run against each entry on the technique list: the operator executes the procedure, your analysts say what their own console showed, the entry is given a verdict, a rule is written or a collection gap is recorded, and the procedure is run again to see whether the change worked. Everything else in the day is scheduling around that loop.
The loop is why the exercise is announced. Both sides watch the same action at the same moment, so the distance between what was done and what was seen closes in minutes rather than in a document three weeks later. On a purple team engagement the deliverable is the detection content those iterations produce, which is why a session that never reaches a second pass on any entry has produced a coverage survey and called it a build.
Plan the day around how many times the loop can close. Execution is the cheapest step in it. The expensive steps are the analysts reconstructing what they saw, the argument about whether a raw log counts as a detection, and the rule being written in front of everyone.
Who has to be in the room for the loop to close
Four roles have to be present, and the loop stalls at a different point when each is missing. The operator runs the procedure. An analyst watches the live console and reports what appeared, without being told what to look for. A detection engineer with write access turns a miss into a rule in the same hour. Somebody who owns collection can switch a log source on, or say plainly that it needs a change request and six weeks.
The last of those is the one most often left out, and leaving it out converts half the findings into a list of things to raise later. A missing log source found at ten in the morning can sometimes be fixed by lunchtime if the person who owns the agent policy is sitting there. If not, every entry resting on that source returns the same verdict for the rest of the day. The dependencies are worth checking before you book anything, and what has to exist before an exercise can measure something is the same list seen from the buying side.
| Role | What they do in the loop | Where the loop stalls without them |
|---|---|---|
| Operator | Runs the agreed procedure and states exactly what was executed and when | There is nothing to observe and the day becomes a workshop |
| Analyst on the live console | Reports what appeared, without being told what to look for | The provider grades its own work from its own tooling |
| Detection engineer with write access | Turns a miss into a rule in the same hour and deploys it for the re-run | Every miss becomes a ticket instead of a detection |
| Owner of collection | Enables a missing log source, or states what enabling it would take | Entries resting on that source return one verdict all day |
| Someone who can authorise a change | Approves a rule going live during the session rather than after it | Rules get written and none of them are running when you leave |
Three verdicts, written down while the screen is still open
Each entry ends in one of three states, and recording which one at the moment it happens is what turns a day of activity into evidence. It alerted: a rule fired and reached a person. It was logged and nothing fired: the telemetry is there, the detection is not. It was never collected: no record of the action exists anywhere you can query.
Here is an illustrative record line, written generically rather than taken from any engagement. Entry: scheduled task registered on a member server by a process whose parent is a remote execution service. Executed 10:42. Analyst console: nothing. Query against the process table at 10:51: parent and child both present, event retained. Verdict: logged, no rule. Rule drafted 11:05, entry re-run 11:20, alert raised four minutes later. That line is worth more at an audit than a coloured square, because it names the procedure, the time and the outcome.
The difference between the second and third verdict decides who does the work next. A logged miss is a detection engineering task and can often be closed before the session ends. A collection miss is a platform task with a cost and a lead time, and it belongs in a different queue. Entries written as procedures rather than as headings are what make the distinction possible at all, which is how the technique list gets built.
| Verdict | What it means | What happens next |
|---|---|---|
| Alerted | A rule fired and the alert reached a person who acted on it | Record the rule and the time to alert, then move on |
| Logged, nothing fired | The telemetry exists and can be queried, but no detection covers it | Detection engineering, usually closable inside the session |
| Not collected | No record of the action exists anywhere you can query | A platform work item with an owner, a cost and a lead time |
Writing the rule without tuning it to the test
The rule written in the room is the point of the day and the easiest thing to get wrong. Under time pressure a rule keys on whatever was most visible in the execution just watched: the name of the binary the operator used, the directory it ran from, the account it happened to run as. It fires on the re-run, everybody records a pass, and it will not fire again on anything done slightly differently.
The test is whether the rule survives a varied procedure. MITRE ATT&CK lists several procedures under one technique identifier for exactly this reason, and asking the operator to run a second one straight after tuning is a five minute check that separates a detection from a signature for one afternoon. Rename the binary, move it to another path, run it as a different account. If the rule goes quiet, it was keyed on the artefact rather than on the behaviour.
Write down what the rule keys on, in one line, next to the rule. Six months later that line is what tells the next engineer whether a product update has invalidated it. It is also what stops a pass being read as coverage of a whole technique when it covers one procedure, which is the freedom a Red Team engagement has and an announced session deliberately gives up.
What actually stalls a day, and what to settle beforehand
Sessions rarely run out of techniques. They run out of the ability to act on them. The blockers that recur are access, change control and attention: no write access to the detection platform on the day, a change freeze that forbids deploying anything, and analysts who are also carrying the live queue and leave the room whenever it fills.
Two more are cheap to settle in the pre-session call. Clocks first: if the operator's timestamps and the platform's sit in different zones or drift apart, reconciling them eats the morning. Then boundaries: agree in writing what may not be run, on which hosts, and who can call a stop. Published testing guidance treats the rules of engagement as a phase of the work rather than as paperwork attached to it, which is the structure NIST SP 800-115 sets out.
Where the constraint is that the estate cannot tolerate the early stages of an intrusion being run against it at all, an assumed breach exercise starts from a foothold you grant and spends the day on the part you wanted watched.
What leaves the room at the end of the day
Five things, and none of them is a slide deck. The rule content itself, in your platform's syntax and in your version control rather than in a vendor appendix. The verdict record. The tuning notes, saying what each rule keys on and what noise it produced during the session. The collection work items, with named owners. And the entries the day did not reach, carried into the next session rather than quietly dropped.
Ownership is the part to insist on in the contract. Detection built during a session and left inside the provider's tooling stops being yours the moment the engagement ends, and it is the one output that keeps working without them. The detect function of the NIST Cybersecurity Framework treats detection as a capability held over time, and a capability you cannot edit is not one you hold.
A session that finishes its list early has not failed. Re-running the same entries next quarter is how detection decay gets found, and a record in the shape above is what makes that comparison mean anything. If the open question is instead whether anyone would notice without being told, that is a different exercise, and which one answers your question is worth settling before you book either.
What the verdict record has to evidence in Abu Dhabi and Dubai
What a UAE supervisor can use is the verdict record, not the fact that a session took place. Four regimes here name security testing. The Central Bank of the UAE binds licensed financial institutions wherever in the country they are established. The Dubai Electronic Security Center binds Dubai government entities and the suppliers that serve them. ADHICS applies to healthcare providers in Abu Dhabi, and the UAE Information Assurance Standard published by NESA sits federally over critical national infrastructure. Each asks in some form whether monitoring works, and a dated line naming a procedure, a verdict and the rule that came out of it answers that far better than an attendance record.
That changes what you ask for on the day rather than how the day runs. A supplier to a Dubai government entity should have the verdict record structured so it maps onto the control it evidences, because the record is the evidence. A healthcare provider in Abu Dhabi under ADHICS gets more from entries chosen against its own control set than from breadth across a matrix. A free zone entity selling into both emirates is often answering to a client's regulator rather than to its own, which is worth establishing before the technique list is signed off. Where the driver is a named threat actor rather than a control, adversary simulation starts from intelligence and ends in the same kind of record.
Frequently asked questions
How long does a purple team session take?
It is sized by the technique list rather than by the calendar. Every entry has to be executed, observed, given a verdict, and then tuned and re-run where nothing fired, so the entries that teach you the most are also the slowest. Agree the list first and let the hours follow from it. Ordering the entries by the questions you most need answered matters more than fitting all of them in.
Do we need a SIEM before a purple team session is worth running?
You need telemetry you can query and somebody who can write and deploy a detection against it. The product name matters less than those two properties. Without queryable telemetry the day produces collection work items rather than rules, which is useful information but a poor use of the room. Settle both before booking, because neither can be fixed on the morning.
Should the SOC be told the session is happening?
Yes. An announced session is the definition of the exercise: both sides watch the same action so the gap between execution and observation closes immediately. If you want to know whether your team would notice without being warned, you are asking a different question, and an unannounced engagement answers it. Running one exercise while hoping it answers the other question wastes both.
Who writes the detection rules, us or the provider?
Draft them together in the room and land them in your platform, in your syntax, under your version control. The provider knows what the procedure leaves behind and your engineers know what your data looks like and what will generate noise at three in the morning. A rule that lives only in the provider's tooling stops being yours when the engagement ends.
