fintech API security

Executive Summary

A Series B fintech startup preparing for its next funding round needed to demonstrate enterprise-grade API security and compliance. CredShields uncovered 23 critical vulnerabilities, implemented an end-to-end remediation program, and guided the client to successful SOC 2 Type II certification all within 3 weeks.

Background

As the startup scaled rapidly, its API ecosystem grew to include:

  • Customer apps
  • Partner integrations
  • Internal microservices
  • Operational dashboards

However, the growth outpaced the team’s ability to standardize security controls, leaving gaps in authorization logic, token handling, and abuse prevention.

The Problem

Key Risks Identified

  1. Broken access control across multiple endpoints
  2. IDOR (Insecure Direct Object Reference) vulnerabilities exposing sensitive user data
  3. Weak token management allowing session persistence
  4. Exposed debug endpoints leaking metadata
  5. Absence of rate limiting, enabling brute-force and enumeration attacks
  6. Insufficient logging and auditability, a direct blocker for SOC 2

Why This Was Critical

The company was entering investor due-diligence, where API security posture is one of the largest deal-breakers in fintech.

CredShields’ Approach

1. Full API Surface Discovery

Mapped every endpoint across staging and production.

2. Manual logic testing

Uncovered business-logic exploits that automated scanners cannot detect.

3. SOC 2 alignment gap analysis

Evaluated system design, monitoring, and access control frameworks.

4. Secure SDLC integration

Implemented new workflows for:

  • Threat modeling
  • Code review standards
  • Access control schemas
  • API governance policies

5. Engineering enablement

Conducted workshops and training for the internal team to ensure long-term compliance.

Technical Breakdown

We identified:

  • 6 IDOR vulnerabilities
  • 5 Broken Authorization cases
  • 3 token lifecycle flaws
  • 2 unsecured admin endpoints
  • Multiple missing validation and sanitization layers

Total Issues Found: 23

Timeline: 3 weeks

Outcome

  • All issues remediated within the engagement period
  • SOC 2 Type II audit passed successfully
  • The company secured its funding round
  • Engineering teams adopted a stable, compliant API architecture framework

Final Status: SOC 2 Certified

Industry Lessons Learned

Scaling APIs without governance leads directly to compliance debt.

Security must be standardized across teams, not implemented piecemeal.

SOC 2 is not just documentation, it requires technical hardening.

Business logic vulnerabilities are the most damaging yet least detectable.

Additional Read

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