Fintech & Banking Penetration Testing

This is where fintech tests earn their fee. We test whether a transfer can be replayed, whether a negative amount produces a credit, and whether firing twenty requests at once lets a withdrawal clear more than once before the balance updates. Race conditions and business-logic flaws in payment code rarely show up in a scanner, and they are exactly what an attacker with an account will try.

PSD2 opened your account data and payment initiation to third parties, and the APIs behind that are a rich target. We test consent enforcement, token scope, and whether an access token issued for one customer can read or move another’s money. Broken object-level authorization on an account endpoint is the open-banking equivalent of leaving the vault unlocked.

The app is often the primary product. We test the compiled iOS and Android binaries and the APIs behind them: what secrets ship in the bundle, whether card data or tokens land in local storage, whether certificate pinning can be bypassed, and whether the client-side controls that gate a transaction are actually enforced on the server.

We map the estate with nmap for exposed services and Burp Suite to capture every request the web app, mobile app and partner integrations make. Fintech recon regularly turns up a sandbox API that shares code with production, an old versioned endpoint that skips a newer control, or a staging environment reachable from the internet.

With accounts across each customer and staff role, we work through authentication, authorization and the money logic by hand. Can a standard user reach an admin function? Can one customer read another’s statements by changing an identifier? Does the transaction limit hold if you split a payment or manipulate the currency field? These are questions only a person can ask well.

We demonstrate real impact safely: reading an account we should not see, forcing a transaction the balance should not allow, or escalating from a normal login to back-office access. We never move real customer funds, and any step that could affect availability is agreed with you in advance and run in a controlled way.

You get an executive summary for the board and regulators and a technical report for engineering. Each finding carries a CVSS score, the financial and regulatory impact spelled out, precise reproduction steps, and a fix ranked by priority. After your team remediates, we retest at no charge and confirm the issue is genuinely closed.

The most common serious fintech finding is an insecure direct object reference on an account, statement or card endpoint: change the identifier, get someone else’s data or the ability to act on their account. On an open-banking API this maps straight to real money and is the first thing a competent attacker checks.

Double-spending a balance, bypassing a transfer limit by splitting or reordering steps, or exploiting the gap between a check and the actual debit. These abuse the rules of your product rather than a coding bug, and they are found by someone who thinks like a fraudster, not by a signature.

Strong customer authentication enforced on the website but skippable on the API, one-time codes with no rate limit, or session tokens that survive a password change. We test whether the second factor is truly required on every sensitive action or just on the screens a designer remembered.

Server-side request forgery in a document or logo uploader that reaches internal services and cloud metadata, SQL injection in older reporting features, and APIs that return more fields than the app shows. We check every parameter, including those buried in JSON bodies and webhook handlers.

If you touch card data, PCI DSS 4.0 requirement 11.4 mandates penetration testing of the cardholder data environment, including segmentation checks that prove the in-scope network is isolated. Our report is structured to serve directly as that evidence.

The Digital Operational Resilience Act brings threat-led and regular testing obligations to financial entities across the EU, and PSD2 sets security expectations for payment services and its open-banking APIs. We scope engagements to support both, and reference the relevant requirements in the report.

ISO 27001 control A.12.6 covers technical vulnerability management, and GDPR Article 32 expects regular testing of your security measures given the sensitivity of financial data. The attestation letter maps findings to these so your certification and privacy evidence is covered in one pass.