Client Background
A high-growth fintech startup preparing to launch a mobile wallet and payment orchestration layer connecting micro-merchants with national financial switches. Handling real customer fiat balances and payment tokens necessitated rigorous compliance audits prior to regulatory licensing.
The Challenge
Before authorizing live public transactions, regulatory authorities and commercial banking partners demanded a verified, independent penetration testing sign-off:
- Automated Scanners Missed Business Logic: Generic SAST/DAST scanner tools repeatedly reported “Green” status despite complex workflow logic flaws buried in multi-step OTP redemption flows.
- Complex Multi-Party APIs: The payment gateway integrated over 148 microservice endpoints across merchant onboarding, QR code checkout, and balance settlements.
- Severe Financial Risk: Any undiscovered authentication flaw or race condition could result in balance manipulation or unauthenticated fund transfers.
Our Solution & Technical Strategy
TheWebSolve conducted a comprehensive grey-box penetration testing engagement spanning two full weeks of active red-team manual testing:
1. Manual Business Logic Testing
We bypassed automated assumptions by systematically testing authorization boundaries:
- IDOR (Insecure Direct Object Reference) testing across merchant transaction ledgers.
- Race condition exploitation on multi-step coupon and wallet recharge webhooks.
- Deep inspection of cryptographic signature validation on webhook callbacks.
2. High-Impact Critical Findings
Our manual testing successfully unmasked:
- Critical IDOR Vulnerability: Allowed an unauthenticated attacker to view transaction receipts and customer phone numbers by incrementing public reference IDs.
- OTP Race Condition Flaw: Allowed multi-threading parallel verification requests to bypass brute-force limits.
- Broken Object Level Authorization (BOLA): In the merchant refund sub-routine.
3. Step-by-Step Remediation & Verified Re-Test
We didn’t just dump a list of CVE numbers. TheWebSolve delivered:
- Proof-of-concept curl commands and video reproductions for each vulnerability.
- Exact code-level remediation blueprints for the client’s engineering team.
- A complete re-test 7 days later confirming that 100% of discovered flaws were mitigated.
Results & Business Impact
- Remediated 4 Critical & High severity flaws before launch, protecting millions of dollars in transaction flows.
- Achieved formal compliance sign-off from commercial banking partners and regulatory auditors.
- Delivered an actionable ongoing security runbook for the internal software development team.
The penetration testing report provided by TheWebSolve was profoundly more comprehensive than our previous vendor's automated PDF scanner. TheWebSolve's offensive security team chain-exploited logic flaws that automated tools completely overlooked, giving our dev team step-by-step reproduction code.