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05 — RESPOND

Objective

Contain, eradicate, and communicate during incidents — including meeting EU statutory reporting deadlines, which are among the strictest in the world.

Core capabilities

ID Capability Description
RS-1 Incident response plan Approved IR plan: definitions, severity classification, roles, escalation, decision authority (who may disconnect production?), out-of-band communications.
RS-2 Playbooks Scenario-specific runbooks for the most likely incident types (phishing/BEC, ransomware, credential compromise, data breach, DDoS, supplier compromise).
RS-3 Incident analysis & forensics Evidence collection and preservation (chain of custody), forensic imaging capability (in-house or retained), root-cause analysis (CSF 2.0 RS.AN).
RS-4 Containment & eradication Technical ability to isolate hosts, disable accounts, block indicators, and revoke sessions — with pre-agreed authority.
RS-5 Incident reporting & communication Internal escalation matrix plus external statutory reporting: national CSIRT/competent authority (NIS2), data protection authority (GDPR), sector regulators (DORA), affected data subjects, law enforcement.
RS-6 Crisis management interface Escalation path from security incident to organisational crisis; link to business continuity structures.
RS-7 Exercises Tabletop and technical exercises at least annually, including management (NIS2 training obligation) and statutory-reporting drills.

EU statutory reporting timelines (build these into playbooks)

Regime Trigger Deadline Recipient
NIS2 Art. 23 Significant incident Early warning ≤ 24 h; incident notification ≤ 72 h; final report ≤ 1 month National CSIRT / competent authority
GDPR Art. 33 Personal data breach (risk to individuals) ≤ 72 h from awareness Data protection authority
GDPR Art. 34 High risk to individuals Without undue delay Affected data subjects
DORA Art. 19 Major ICT-related incident (financial entities) Initial ≤ 4 h from classification / ≤ 24 h from awareness; intermediate ≤ 72 h; final ≤ 1 month Competent financial authority

Member-state transpositions of NIS2 may add national specifics — maintain a country annex for each jurisdiction you operate in. Community contributions of national annexes are welcome (see CONTRIBUTING).

Case closure taxonomy

Standardise how every case closes — it is the foundation of honest metrics, tuning feedback and comparable statistics: true positive with impact (a CIA attribute was breached → incident; reporting duties assessed), true positive without impact (malicious intent, no harm done), indeterminate, or false positive (→ tuning loop, doc 13). For incident-type classification, the open VERIS vocabulary (malware, hacking, social, misuse, error, physical, environmental) keeps year-over-year and peer statistics comparable.

CIA mapping

Capability C I A Rationale
RS-2 Playbooks Ransomware playbooks defend A/I; breach playbooks defend C.
RS-3 Forensics Evidence integrity (hashing, chain of custody) is an Integrity discipline.
RS-4 Containment Containment trades short-term Availability for protection of C and I — the decision authority for that trade-off must be pre-agreed (GOVERN).

Roles & staffing

  • Incident manager/commander — coordinates; distinct from technical lead in larger incidents.
  • Technical responders — often the same analysts as DETECT.
  • Legal/DPO and communications — mandatory members of the extended IR team.
  • Retainers — consider external DFIR retainer at Level 2+ if in-house forensics is not viable.

Maturity criteria

Level Criteria
1 — Initial Ad-hoc response by IT; no approved plan; reporting duties not mapped.
2 — Managed Approved IR plan; playbooks for top 3–5 scenarios; statutory reporting contacts and templates prepared; annual tabletop.
3 — Established Containment actions pre-authorised and technically automatable; forensic capability (in-house or retained); exercises include management and reporting drills; post-incident reviews feed improvements.
4 — Optimising Response metrics (MTTC/MTTR) trended; cross-functional crisis exercises with suppliers; automation of enrichment and containment with human approval gates; lessons systematically drive PROTECT/DETECT changes.

EU regulatory hooks

  • NIS2 Art. 21(2)(b) incident handling; Art. 23 reporting (see table above).
  • GDPR Art. 33/34 — breach notification; document all breaches internally, even those not notified (Art. 33(5)).
  • DORA Art. 17–19 — ICT incident management, classification and reporting for financial entities.
  • ENISA / national CSIRT good practice — align severity taxonomies with your national CSIRT's scheme where one exists to ease reporting.

External dependencies

Dependency Party Type Agree up front
Containment beyond pre-mandated scope (crown jewels) Service owner / executive per charter §4 [GATE] Decision criteria + deputy; drill it — this gate at 03:00 is the whole point of the charter
Execution of containment and restoration actions IT operations [HARD] 24/7 reachability; actions from the containment catalogue rehearsed
Notification decisions (GDPR/NIS2/press) Legal / DPO / communications [GATE] Draft templates pre-approved; who can be woken
External statements and customer communication Communications [HARD] Holding statements ready; single spokesperson rule
Insider-related cases HR + legal [GATE] Process agreed before the first case, incl. evidence handling
Forensics beyond in-house capability External DFIR retainer [HARD] Retainer signed, response time, onboarding pack ready

Sources

  • NIST SP 800-61 Rev. 3, Incident Response Recommendations and Considerations for Cybersecurity Risk Management (2025). https://doi.org/10.6028/NIST.SP.800-61r3
  • NIST CSF 2.0 (CSWP 29), RESPOND function.
  • FIRST, Computer Security Incident Response Team (CSIRT) Services Framework v2.1. https://www.first.org/standards/frameworks/csirts/csirt_services_framework_v2.1
  • Directive (EU) 2022/2555 (NIS2) Art. 23; GDPR Art. 33–34; Regulation (EU) 2022/2554 (DORA) Art. 17–19.
  • VERIS — Vocabulary for Event Recording and Incident Sharing. http://veriscommunity.net
  • Microsoft incident response playbooks (baseline runbooks; adapt to your environment). https://learn.microsoft.com/security/operations/incident-response-playbooks
  • CISA, Federal Government Cybersecurity Incident and Vulnerability Response Playbooks (2021). https://www.cisa.gov

Open CDC Framework (OCDF) — CC BY 4.0. Credits: 19-references.md.