UnlockSec

Sample Assessment Report

Redacted for confidentiality

Q2 2025

Architecture Review

Security Architecture Assessment

Client

Confidential Client — FinTech Startup (Series B)

Scope

AWS-hosted microservices architecture (14 services), API gateway, authentication service, data processing pipeline, third-party integrations (3 payment providers, 2 identity providers)

Duration

7 business days

Standard

STRIDE Threat Modelling

Executive Summary

UnlockSec performed a threat-model-driven architecture review of the client's cloud-native financial platform. The review identified fundamental trust boundary weaknesses between microservices, an absence of secrets management leading to credentials stored in environment variables, and a data flow design that routes raw PII through a logging service without field-level filtering.

Methodology

STRIDE Threat ModellingPASTA MethodologyAWS Well-Architected Security PillarNIST Cybersecurity Framework

Sample Findings

ARCH-001

PII Data Flow — Unfiltered Logging of Financial Records

Critical

Description

The centralised logging pipeline ingests raw API request and response payloads without field-level filtering. This causes customer PAN, CVV, bank account numbers, and SSN values to be stored in plaintext in CloudWatch Logs, accessible to any principal with CloudWatch read permissions (currently 47 IAM users).

Recommendation

Implement field-level filtering in the logging pipeline to redact sensitive fields before ingestion. Apply data classification tagging to all data flows. Conduct a GDPR/PCI-DSS data flow mapping exercise.

ARCH-002

Microservice Trust — No Service-to-Service Authentication

High

Description

Internal microservice communication is unauthenticated — any service within the VPC can call any other service's internal API endpoints without presenting credentials. Compromise of any single microservice provides unrestricted access to all internal APIs.

Recommendation

Implement mutual TLS (mTLS) for all service-to-service communication. Use AWS IAM service accounts with instance profile roles. Consider a service mesh (AWS App Mesh) for certificate management and policy enforcement.

ARCH-003

Secrets Management — Credentials in Lambda Environment Variables

High

Description

Database passwords, third-party API keys, and JWT signing secrets are stored as Lambda function environment variables in plaintext. These are visible to any IAM principal with lambda:GetFunctionConfiguration permission and are logged in CloudTrail.

Recommendation

Migrate all secrets to AWS Secrets Manager or Parameter Store (SecureString). Rotate all currently exposed credentials. Restrict lambda:GetFunctionConfiguration to the deployment pipeline role only.

ARCH-004

Missing Egress Controls — Data Exfiltration Path

High

Description

All VPC subnets have unrestricted internet egress via a NAT gateway with no network-level filtering. A compromised Lambda function or container can exfiltrate data to any internet destination without detection or blocking.

Recommendation

Implement VPC endpoint policies to restrict AWS service access. Add an egress firewall (AWS Network Firewall) with domain allowlist filtering. Instrument all outbound connections with VPC Flow Logs and CloudWatch alarms.

* Showing 4 of 33 total findings. Full report provided upon engagement.

Risk Summary

Critical1
High7
Medium12
Low8
Info5
Total Findings33

Deliverables Included

  • STRIDE threat model with attack surface diagram
  • Data flow security analysis with PII mapping
  • Trust boundary assessment per microservice
  • Secure architecture target state recommendations
  • Risk-ranked remediation roadmap (30/60/90-day plan)

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