CYBRARY The setting is the vulnerability
Unlike kerberoasting, the attacker needs nothing but the account name. Until pre-authentication is re-enabled, the exposure returns the moment the password is cracked again.
C-343·Cross-platform·35 min
The account with pre-authentication off Start this lab
The domain controller hands back an AS-REP for an account that never required pre-authentication, which is an offline crack waiting to happen. Find the account, prove the setting rather than the alert, and close the exposure without touching the finance user in the same batch.
Mission brief · C-343
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
Why this matters
AS-REP roasting needs no credentials at all: if an account does not require Kerberos pre-authentication, the domain controller hands anyone an encrypted blob to crack offline. It is a configuration exposure that reads like an attack.
Concepts
Reset and re-enable, in that order
A reset with pre-authentication still off just gives the attacker a fresh blob to crack. Both actions together are what closes it.
Batches contain innocents
Alert batches group by time, not by cause. The finance user beside the legacy account is graded: scope the action to the account carrying the setting.
Objectives graded
- Tell AS-REP roasting apart from ordinary Kerberos failures
- Prove the disabled pre-authentication setting on the account
- Close the exposure and reset the credential without harming the peer
Live walkthrough
The reference response, executed by the same engine that grades your attempt. Yours will differ — the rubric reads end state and evidence, not the shape of your workflow.
- 1.Approve consequential actionpromptapproval gateApprove consequential action
- 2.Write case field credentialRefactioncredentialRef → vault/soc-automation
- 3.Attach evidence: case/soar-c-343/evidenceactionThe learner attached at least one linkable piece of evidence to the case.
- 4.Write case field closureNoteactionclosureNote → written
- 5.Write case field roastedAccountactionroastedAccount → svc-legacy
- 6.preauthRequired on usr-svc-legacyactionusr-svc-legacy.preauthRequired → true
- 7.enabled on usr-finance-peeractionusr-finance-peer.enabled → true
Gate approved — 100%
12 of 12 rubric rules hold.
Gate denied — 91%
Refusing the consequential action is a defensible choice with a measured cost; the difference is what the lab is teaching.
- pass behavior · The workflow reached a terminal success state on the graded run.
- pass safety · A consequential action passed through a human approval gate.
- pass efficiency · No non-idempotent operation was retried without an idempotency key.
- pass configuration · Every action node resolves its secret from the vault, never an inline field.
- pass investigation · The learner attached at least one linkable piece of evidence to the case.
- pass explanation · The case carries an analyst closure note explaining the outcome.
- pass behavior · No innocent asset in the alert batch was contained, disabled or revoked.
- pass configuration · The playbook survived the integration faults it met and still finished.
- pass investigation · Nothing was changed in the estate before evidence had been gathered.
- pass investigation · The learner named the account whose pre-authentication was disabled.
- pass behavior · Pre-authentication was turned back on, which closes the exposure itself.
- pass safety · The innocent account in the same alert batch was left working.
MITRE ATT&CK coverage
An account without Kerberos pre-authentication hands out a crackable AS-REP to anyone who asks.
| Technique | Name | Tactic |
|---|---|---|
| T1558.004 | Steal or Forge Kerberos Tickets: AS-REP Roasting | Credential Access |
| T1110.002 | Brute Force: Password Cracking | Credential Access |
| T1078 | Valid Accounts | Defense Evasion |
What each rubric rule proves
The workflow reached a terminal success state on the graded run.
behavior · weight 20
A consequential action passed through a human approval gate.
safety · weight 15
No non-idempotent operation was retried without an idempotency key.
efficiency · weight 10
Every action node resolves its secret from the vault, never an inline field.
configuration · weight 10
The learner attached at least one linkable piece of evidence to the case.
investigation · weight 10
The case carries an analyst closure note explaining the outcome.
explanation · weight 10
No innocent asset in the alert batch was contained, disabled or revoked.
behavior · weight 15
The playbook survived the integration faults it met and still finished.
configuration · weight 15
Nothing was changed in the estate before evidence had been gathered.
investigation · weight 10
The learner named the account whose pre-authentication was disabled.
investigation · weight 20 · T1558.004 Steal or Forge Kerberos Tickets: AS-REP Roasting (Credential Access)
Pre-authentication was turned back on, which closes the exposure itself.
behavior · weight 20 · T1558.004 Steal or Forge Kerberos Tickets: AS-REP Roasting (Credential Access)
The innocent account in the same alert batch was left working.
safety · weight 15 · T1078 Valid Accounts (Defense Evasion)
Common mistakes
- Resetting the password and leaving pre-authentication disabled.
- Acting on every account in the alert batch.
- Confusing AS-REP roasting with ordinary Kerberos pre-authentication failures.
Same idea, three vendors
Vocabulary is generated from the teaching profiles, so it always matches what the consoles render.
| Concept | Cortex Forge | Summit SOAR | Storyline |
|---|---|---|---|
| approval | Manual task | Prompt | Page |
Where does this value come from?
The same reference to an enrichment node's verdict, written three ways:
- Cortex Forge: ${enrich-sender.verdict}
- Summit SOAR: enrich-sender.verdict
- Storyline: <<enrich-sender.verdict>>
The same concepts in shipping products
The consoles you practice in use teaching names. These are the words the real vendors print in their own documentation, so the vocabulary survives the day you sit in front of a production tenant.
| Concept | Cortex XSOARXSOAR 8.x | Splunk SOARSplunk SOAR 6.x (formerly Phantom) | TinesTines (2026 cloud) | Microsoft Sentinel + Logic AppsSentinel (Defender portal, 2026) | Google SecOps SOARSecOps SOAR (formerly Siemplify) | Swimlane TurbineTurbine (2026) | Torq HyperautomationTorq (2026) | IBM QRadar SOARQRadar SOAR (Resilient) 51.x | ServiceNow Security OperationsSecOps (Flow Designer era) |
|---|---|---|---|---|---|---|---|---|---|
| approval | Manual (data collection) task | Prompt block | Page (form) / Send to Chat | Approval action (Teams / email) | Manual action | Task / approval action | Approval step (Torq Chat / Slack) | Manual task / phase gate | Approval activity |
What transfers
The pattern — a permissive setting that makes an attack free — recurs in unconstrained delegation, legacy authentication and anonymous binds.