METHODOLOGY
PASTA Threat Modelling
We conducted threat modelling using PASTA (Process for Attack Simulation and Threat Analysis). PASTA provides a risk-centric approach across seven stages:
- Define Business Objectives: Critical objectives for 5G network security defined
- Technical Scope: 4G EPC, 5G NSA, 5G SA architecture comparison
- Decomposition: Component-based: Authentication, Core/SBA, Edge/MEC, Slicing
- Threat Analysis: 15 threats identified via the MITRE ATT&CK framework
- Vulnerability Analysis: Vulnerability details and 3GPP references mapped per threat
- Attack Simulation: Attack scenarios modelled across 11 kill chains
- Risk Analysis: 16-factor scoring using the OWASP Risk Rating
Why 4G Threat Models Fall Short
The 4G security architecture relies on 4 fundamental assumptions. 5G SA architecture breaks every one:
OWASP Risk Rating
Each threat is scored across 16 factors, grouped into 4 categories:
Threat Agent
- Skill Level
- Motive
- Opportunity
- Size
Vulnerability
- Ease of Discovery
- Ease of Exploit
- Awareness
- Intrusion Detection
Technical Impact
- Loss of Confidentiality
- Loss of Integrity
- Loss of Availability
- Loss of Accountability
Business Impact
- Financial Damage
- Reputation Damage
- Non-Compliance
- Privacy Violation
Calculation: Likelihood = (TAF + VF) / 2, Impact = (TI + BI) / 2. Severity matrix: CRITICAL (L≥6 and I≥6), HIGH (L≥6 or I≥6), MEDIUM (L≥3 or I≥3), LOW.
Experimental Validation
10 threats have been validated with academic sources. Testing was conducted on 8 COTS UE devices. For each threat: source paper, test method, device count, and validation result are available.
Sensitivity Analysis
Each OWASP factor has been tested with ±1 shift. This measures score robustness. Threats showing large shifts should be evaluated more carefully.