EU Cyber Regulation Will Fail Without a Common Threat Taxonomy (Enter TLCTC)

Date: 2025/09/28 | Framework: Top Level Cyber Threat Clusters (TLCTC)

Thesis: The EU’s flagship cyber regulations (NIS2, the Cybersecurity Act, and the Cyber Resilience Act) will under-deliver on actual cyber risk reduction because they lack a shared, cause-based understanding and categorization of cyber threats. They would materially benefit from adopting the Top Level Cyber Threat Clusters (TLCTC) as a unifying taxonomy.

TL;DR

Compliance is surging, risk is not dropping accordingly. The gap? Europe regulates outcomes and process well (incidents, reporting, assurance, lifecycle), but does not standardize causes—the initial threats that open the door. TLCTC fills that gap with a simple, universal, cause‑oriented threat taxonomy (10 clusters) and an attack‑path notation that makes reporting, prioritization, and controls consistent across sectors.

Why this matters now

Across the EU, NIS2 broadens who must manage cyber risk and how to report it. The Cybersecurity Act enables EU‑wide certification schemes. The new Cyber Resilience Act (CRA) forces manufacturers to build and maintain secure products and report severe incidents and actively exploited vulnerabilities. These are big wins for governance and accountability.

But boards, regulators, CSIRTs, and vendors still struggle to speak the same threat language. Reports arrive framed as effects ("ransomware outage", "data breach"), not as causes (the initial abuse path). Without a shared threat vocabulary, three problems persist:

Inconsistent reporting & metrics – Two identical attacks get classified differently by sector/authority. Apples-to-oranges data cripples EU‑level situational awareness.
Misaligned controls – Controls are selected for symptoms ("stop ransomware") instead of the initial threats (e.g., #9 Social Engineering or #4 Identity Theft), wasting budget.
Fragmented supply‑chain risk – CRA and NIS2 demand supplier assurance, yet buyers and vendors lack a common threat model to contract against.

Reframing EU cyber through TLCTC

Within the TLCTC framework, every compromise begins when an attacker exploits a generic vulnerability via one of ten Top Level Cyber Threat Clusters. We treat threats as causes (not effects), and we track multi‑stage attacks with a compact attack‑path notation.

The 10 TLCTC clusters (strategic layer)

#1 Abuse of Functions – Misuse of a legitimate feature/logic.
#2 Exploiting Server – Flaws in server‑side code (e.g., injection, overflow).
#3 Exploiting Client – Flaws in client‑side code (browser, reader, agent).
#4 Identity Theft – Credentials/tokens/keys acquired or misused.
#5 Man‑in‑the‑Middle – Attacker abuses position on the path.
#6 Flooding Attack – Capacity exhaustion/DoS (network, API, CPU, quotas).
#7 Malware – Execution of foreign code/LOLBAS.
#8 Physical Attack – Unauthorized physical interaction/interference.
#9 Social Engineering – Human manipulation (purely psychological).
#10 Supply Chain Attack – Compromise via trusted third‑party components or services.

Axioms that matter for regulators: threats are causes (not events), credentials are control elements (not just data), every attack path is a sequence of these clusters, and the model is generic (works for OT/IT/IoT alike).

Attack‑path notation (operational layer)

We describe an attack end‑to‑end as a sequence of clusters. Example common case:

Ransomware reality: #9 → #7 → #4 → (#1 + #7)

#9 Social Engineering (phish gets user to run macro)
#7 Malware (loader/beacon executes)
#4 Identity Theft (token theft or credential replay)
#1 Abuse of Functions (legit admin tools abused) + #7 Malware (encryptor deployed)

This notation cleanly separates cause from effect and is compact enough for incident forms, dashboards, and supplier attestations.

Where EU law is strong—and where it’s silent

Strong:

Clear incident stages & deadlines (early warning → 72h notification → final report).
Risk‑management baselines (policies, incident handling, supply‑chain security, secure development, MFA, etc.).
Coordinated vulnerability disclosure and a European vulnerability database.
CRA‑driven secure product lifecycle and single reporting platform for vulnerabilities/incidents.

Silent (or inconsistent):

No mandated cause‑based threat taxonomy across sectors.
Incident templates ask for the "type of threat/root cause" but don't define a standard dictionary—leading to heterogeneous labels ("APT", "phishing", "ransomware"), which mix actor, vector, and effect.
Supply‑chain due diligence lacks a unified threat‑to‑control mapping that buyers and vendors can both adopt.

Bottom line: EU law sets the process (who, when, how) but not the language of causes (what, exactly, happened at the start).

How TLCTC plugs in—without changing the law

Think of TLCTC as the Rosetta Stone that sits underneath existing requirements:

NIS2 reporting: Standardize the "type of threat or root cause" field with TLCTC. Every notification carries an attack‑path string, e.g., #9 → #7 → #4 …. Aggregate across sectors with clean, comparable metrics (e.g., 38% of significant incidents begin with #4 Identity Theft this quarter).
CRA manufacturer duties: Tie vulnerability classes and severe incidents to the initiating TLCTC cluster(s). E.g., an auth‑bypass is #1 Abuse of Functions, a deserialization bug is #2 Exploiting Server. SBOM risk triage can then prioritize suppliers with high exposure to #10 Supply Chain Attack.
Cybersecurity Act (certification): Map certification controls to clusters (10×5 matrix vs. NIST CSF functions) so schemes prove coverage against causes, not just generic capability.

This is a non‑disruptive add-on: regulators can recommend or require a TLCTC field in templates and supervisory guidance; entities adopt it in policies, SOC playbooks, and supplier questionnaires.

Example: Same incident, clearer insight

Before (effect‑oriented): "We suffered ransomware from a phishing email."

After (cause‑oriented with TLCTC): #9 → #7 → #4 → (#1 + #7)

Control mapping: #9 (awareness, phishing-resistant auth), #7 (app allow‑listing, EDR/containment), #4 (FIDO, PAM, vaulting), #1 (admin tiering, just‑in‑time privileges).
Metrics: First‑stage distribution shows #9 leading 62% of starts this quarter → invest in controls that cut initial paths, not just recovery.
Supervision: CSIRTs can cross‑compare sectors on causal patterns and publish targeted advisories (e.g., spike in #5 MitM on API traffic).

What would change on Day 1 of TLCTC adoption

Incident forms gain one mandatory line: Attack Path (TLCTC).
Dashboards show start‑of‑attack distributions by sector, Member State, supplier class.
Supplier due diligence uses a short TLCTC questionnaire: exposure, controls, and recent incidents by cluster.
Board risk reports track quarter‑over‑quarter shifts in initiating clusters and control efficacy per cluster.

Quick reference: the TLCTC clusters (with control intent)

#1 Abuse of Functions → harden business logic, constrain scope, least privilege.
#2 Exploiting Server → secure SDLC, SAST/DAST, memory‑safe patterns, patch SLAs.
#3 Exploiting Client → browser isolation, rapid patching, hardening of clients/agents.
#4 Identity Theft → phishing‑resistant MFA, key management, PAM, device‑bound tokens.
#5 MitM → strong TLS, certificate pinning, secure routing, DNSSEC where feasible.
#6 Flooding Attack → capacity planning, rate limiting, scrubbing, auto‑scale fail‑safes.
#7 Malware → application allow‑listing, EDR, egress controls, scripted tool restrictions.
#8 Physical Attack → tamper protection, secure facilities, media control.
#9 Social Engineering → training, simulation, protected workflows (no‑bypass approvals).
#10 Supply Chain Attack → supplier assurance, code signing, update hygiene, SBOM.

Objections & answers

“Isn’t ‘ransomware’ already a category?”

No—ransomware is an effect. TLCTC insists on causes (#9, #7, #4, #1, etc.). This prevents actor/effect/control confusion and makes data comparable.

“Won’t this create reporting burden?”

Minimal. One short line per incident, plus a cheat‑sheet. The payoff in analytics and targeted guidance is large.

“Does this replace NIST, MITRE, or ISO?”

No. TLCTC is the strategic cause layer. You still use NIST CSF for control governance and MITRE ATT&CK for technique detail—both mapped back to the 10 clusters.

Call to action (for regulators, CSIRTs, and entities)

Add TLCTC to templates – Make “Attack Path (TLCTC)” a required field in incident/vulnerability forms.
Publish cluster stats – CSIRTs should release quarterly causal distributions and advisories by cluster.
Procure by cluster – Mandate supplier attestations of controls per TLCTC cluster; align CRA conformity claims to causes.
Train leaders – Board‑level training: causes vs. effects, and how budget tracks to initial attack paths.

Notes & references (for readers)

This article discusses the EU’s NIS2 Directive (general cybersecurity obligations, incident reporting and CSIRT roles), the Cybersecurity Act (ENISA and EU‑wide certification), and the Cyber Resilience Act (security requirements and reporting for products with digital elements). It proposes TLCTC as a neutral, cross‑framework taxonomy to standardize the cause side of incidents and vulnerabilities across sectors and Member States.

TLCTC Blog - 2025/09/28