Mission brief · N-405

Tier 3 analyst on the incident response bench

Tier 3 — deep host and forensics

Business important

Track default

You are acting as

the break-glass IR account `svc-ir`, checked out of the vault for this incident — never the compromised identity

How you got here

The detection fired in the EDR console. You opened a live-response session from that detection, so your shell rides the EDR agent channel — containing the host will *not* cut you off, which is exactly why you contain from here rather than over SSH.

Your access

EDR console (detections + live response)
Endpoint detection & response
- Read the detection and process tree
- Look up host criticality, owner and VIP flags
- Open a live-response session on the host
- Contain the host over the agent channel
- Not yours: Disable user accounts (that's the identity team)
- Not yours: Delete evidence
Live-response shell on the affected host
Host shell session
- Read the filesystem, logs and running state
- Collect a triage package
- Not yours: Reboot or reimage without owner approval

What's at stake

The affected host

Owner: The system's business owner, named on the asset record

Containing a host you haven't identified can stop revenue. Check criticality and owner before you isolate anything.

Rules of engagement

You may act alone

Investigate from the live-response session
Collect evidence and triage packages
Contain a standard-criticality host

Ask a human first

Containing a mission-critical host — asset owner and on-call manager first
Disabling a user identity — identity team, and HR/legal if it looks like an insider

How much help do you want?

Objectives stay open and every step explains why it matters before it tells you what to run. Hints are free.

Graded case walkthrough

Open a lab as a live case and advance it one node at a time. The score beside each step is the lab rubric re-evaluated against what the engine actually did.

Lab

Dispatch say the yard crawls and the cabling record is four years stale. Sit at the yard seat, ping each segment, walk the path hop by hop and read the physical layer off the kit: what each leg is made of, how far it runs and what it negotiated. Then say which of the two faults the yard actually feels.

Range guide

Guided

Every step explains why it matters before it tells you what to do. Reasoning is free in guided mode.

Prove it

1. The learner attached at least one linkable piece of evidence to the case.
Why this step: The learner attached at least one linkable piece of evidence to the case. It carries 10 points on the investigation dimension.
2. Nothing was changed in the estate before evidence had been gathered.
Why this step: Nothing was changed in the estate before evidence had been gathered. It carries 10 points on the investigation dimension.
3. The path was measured from the yard seat rather than described from the ticket.
Why this step: The path was measured from the yard seat rather than described from the ticket. It carries 15 points on the investigation dimension.
4. The seat's own access medium was identified before anything upstream was blamed.
Why this step: The seat's own access medium was identified before anything upstream was blamed. It carries 10 points on the investigation dimension.
5. The longest leg on the path back to head office was named from the path view.
Why this step: The longest leg on the path back to head office was named from the path view. It carries 10 points on the investigation dimension.
6. The length of that leg was read off the model rather than estimated.
Why this step: The length of that leg was read off the model rather than estimated. It carries 10 points on the investigation dimension.
7. The routed hops on the path were counted from a real traceroute.
Why this step: The routed hops on the path were counted from a real traceroute. It carries 10 points on the investigation dimension.

Decide and act

1. The workflow reached a terminal success state on the graded run.
Why this step: The workflow reached a terminal success state on the graded run. It carries 20 points on the behavior dimension.
2. A reversible action passed through a human approval gate.
Why this step: A reversible action passed through a human approval gate. It carries 15 points on the safety dimension.
3. No non-idempotent operation was retried without an idempotency key.
Why this step: No non-idempotent operation was retried without an idempotency key. It carries 10 points on the efficiency dimension.
4. Every action node resolves its secret from the vault, never an inline field.
Why this step: Every action node resolves its secret from the vault, never an inline field. It carries 10 points on the configuration dimension.
5. No innocent asset in the alert batch was contained, disabled or revoked.
Why this step: No innocent asset in the alert batch was contained, disabled or revoked. It carries 15 points on the behavior dimension.
6. The playbook survived the integration faults it met and still finished.
Why this step: The playbook survived the integration faults it met and still finished. It carries 15 points on the configuration dimension.
7. The speed the over-length run actually negotiated was recorded.
Why this step: The speed the over-length run actually negotiated was recorded. It carries 10 points on the configuration dimension.
8. Nothing in the estate was contained or disabled over a performance ticket.
Why this step: Nothing in the estate was contained or disabled over a performance ticket. It carries 10 points on the safety dimension.

Write it up

1. The case carries an analyst closure note explaining the outcome.
Why this step: The case carries an analyst closure note explaining the outcome. It carries 10 points on the explanation dimension.

Your cases

No cases opened yet.