Containment Playbooks

Overview

The first thirty minutes after an incident is confirmed determine whether it stays a single-endpoint or single-mailbox event or becomes a portfolio-wide one. This skill is the first-response sequence for the incident classes an MSP sees most often. It is deliberately ordered — containment before eradication, eradication before recovery, recovery before notification — because doing these out of order (for example, resetting a compromised password before revoking active sessions) leaves an attacker's live session valid even after the "fix."

This skill does not replace a full incident response plan or a client's own IR contract terms. It is the playbook for the first response actions a technician or agent takes the moment an incident class is identified, before a deeper investigation or a formal incident report is built (see Incident Timeline Builder for that phase).

Anti-triggers

• Executing the action in one vendor — approving a Huntress remediation, isolating a SentinelOne endpoint, or disabling a CIPP user is that connector's surface; use huntress-incidents, sentinelone-alerts, threatlocker-computers, or cipp-users. This skill supplies the ordering and the tool-family map, not the call.
• Investigating a detection rather than stopping it — drill-down across assets, detections, and vulnerabilities is blackpoint-incident-response or sentinelone-threat-hunting.

Step Zero: Confirm What's Connected

Call conduit__search_tools before assuming which tool handles which step below. A client with Datto RMM but no CIPP connection can still isolate a device but cannot revoke M365 sessions through this pack — that step must be flagged as unavailable and handed to whatever manual/console process the MSP uses instead. Never silently skip a containment step; if the connector for it isn't present, say so explicitly and name the fallback (manual console action, PSA ticket note, or escalation).

Playbook: Compromised Account

Order	Action	Tool family
1	Revoke all active sessions/refresh tokens for the account	CIPP / Entra (session revocation)
2	Disable the account (do not delete — preserves forensic state)	CIPP / Entra
3	Review and remove any inbox rules, forwarding rules, or delegate access created during the compromise window	CIPP / M365 mailbox rules
4	Reset the account password to a fresh, non-reused value	CIPP / Entra
5	Force MFA re-enrollment, invalidating any attacker-registered MFA method	CIPP / Entra
6	Check for lateral movement — other accounts with new sign-ins from the same source IP/ASN in the compromise window	CIPP audit logs / SIEM
7	Re-enable the account only after 1–5 are confirmed complete	CIPP / Entra
8	Document the timeline and notify the affected user and any downstream recipients of attacker-sent mail	PSA / documentation

Order matters: reset the password (step 4) only after revoking sessions (step 1) — a password reset alone does not invalidate an already-issued session token.

Playbook: Malware / Ransomware Detection

Order	Action	Tool family
1	Isolate the affected device from the network (network isolation, not shutdown — shutdown destroys volatile forensic evidence)	EDR (SentinelOne/Huntress) or RMM
2	Confirm isolation succeeded — device shows isolated/quarantined in the console	EDR
3	Check for the same file hash / indicator on other endpoints in the same tenant	EDR
4	If ransomware behavior is confirmed: check backup job status and last-known-good restore point immediately — do not wait for full eradication to check this	RMM / backup platform
5	Identify patient zero and initial access vector (phishing, exposed RDP, exploited service) where evidence allows	EDR / RMM / documentation
6	Run the EDR's remediation/rollback action if available; otherwise scope for reimage	EDR
7	Re-image or reissue credentials for any accounts that were active on the device during the infection window	RMM + CIPP/Entra
8	Hold the device off the network until a clean scan and patch baseline are confirmed	EDR / RMM

Never skip step 4 for ransomware-classified events, even if eradication looks straightforward — backup viability is the single fact that most changes the client conversation, and it degrades the longer it's unchecked (some ransomware families delay backup-target encryption).

Playbook: Business Email Compromise (BEC)

See BEC Response for the full detection and response sequence. In summary, the containment order is: revoke sessions → audit and remove forwarding/inbox rules → reset password → force MFA re-enrollment → identify and notify any recipients of attacker-sent financial-fraud email before the client's own outreach does.

Playbook: Exposed Credential

Order	Action	Tool family
1	Determine scope — is this a single account's password, or a shared/service account credential that touches multiple systems?	Documentation (IT Glue/Hudu) / PSA
2	Revoke active sessions for the affected account(s)	CIPP / Entra, or the relevant vendor console for non-M365 credentials
3	Rotate the credential everywhere it is used — check documentation for every system referencing it before declaring rotation complete	Documentation / CIPP / relevant vendor
4	If the credential had elevated or admin scope, review recent activity for signs of misuse before rotation (rotation can end an active session but won't retroactively reveal what already happened)	Audit logs (CIPP / EDR / SIEM)
5	Force MFA re-enrollment if the credential belongs to an MFA-protected account	CIPP / Entra
6	Update the credential's record in documentation and note the rotation date/reason	Documentation platform

A credential found in a public breach dump or paste site should be treated as exposed even with no confirmed misuse — rotate on discovery, don't wait for evidence of use.

Common Principles Across All Playbooks

1. Contain before you investigate deeply. Stopping the bleeding comes before root-cause analysis. A device can stay isolated while forensics continues.
2. Preserve evidence. Prefer network isolation over shutdown, disable over delete, and log every action taken with a timestamp — this becomes the incident timeline.
3. Notify only after containment is underway, not before — a premature notification without a stated containment status creates client anxiety without giving them anything actionable.

Related Skills

• Alert Severity Normalization — how to decide whether an incident warrants this playbook's urgency.
• BEC Response — the detailed BEC-specific sequence.