Cross-account access to transactions and statements
An ID in a request that isn't checked against the caller's account or tenant, exposing balances, payees or statements of other customers.
Industries
Penetration Testing for Fintech
In fintech, a broken authorization check doesn't just leak data. It moves money. We test the logic, the APIs and the integrations your partners rely on.
Why it's different
Security testing for fintech products
Fintech products sit between your customers’ money and the institutions that hold it. That changes what a security flaw costs. A missing authorization check in most SaaS products exposes data. In a payments or lending platform, the same flaw can let one customer move another customer’s funds, approve their own loan or settle a payment that never happened.
Fintech also carries more scrutiny than most software. Sponsor banks, card programme managers, payment processors and enterprise customers all review your security before they sign, and regulators expect regulated firms to manage the risk in their suppliers. A clear penetration test report is one of the documents you will be asked for most often.
Where fintech testing differs
The highest-impact issues are rarely exotic. They come from how money flows through the product:
- Authorization on every financial object. Accounts, cards, payees, transactions, statements and documents each need checking against the caller on every request.
- Business rules enforced on the server. Limits, approvals, fees and eligibility must hold even when someone edits the request directly.
- Concurrency. Balances and limits must stay correct when the same action arrives many times at once.
- Trust in third parties. Callbacks from processors and banks, and data from KYC vendors, must be verified, not assumed.
We test these by hand, with accounts for every role and test data from your providers’ sandboxes. Automated scanners help with coverage, but they can’t tell that a transfer should have needed a second approval.
Common findings
What attackers go after
The issues we look for first in fintech products. Typical severity shown; real ratings depend on your system.
Payment and transfer logic abuse
Negative amounts, currency or rounding manipulation, skipped approval steps, or limits enforced only in the client.
Race conditions on balances and limits
Parallel requests that spend the same balance twice, exceed a daily limit or redeem a reward more than once.
Weak verification of provider callbacks
Webhooks from payment processors, banks or KYC vendors accepted without signature checks, so an attacker can mark payments as settled.
Account takeover through recovery flows
Password reset, device enrolment and SIM-change flows that bypass the strong authentication used at login.
Over-trusted partner and open banking integrations
API keys with broad scopes, missing per-partner authorization, and sensitive data returned to partners who don't need it.
Sensitive data in KYC uploads and exports
Identity documents stored at guessable URLs, or reports and exports generated without checking who asked for them.
Scope
Recommended scope
Where we usually start. We'll confirm the right scope with you on a scoping call.
Web Application Penetration Testing
Customer dashboards, admin and back-office tools, with every role and approval flow tested.
API Penetration Testing
Public, partner and mobile-backend APIs, including payment, transfer and webhook endpoints.
Mobile App Penetration Testing (iOS & Android)
Banking and wallet apps, including local data storage, authentication and device binding.
Cloud Security Testing (AWS, Azure, GCP)
The cloud accounts that hold cardholder data, keys and production databases.
FAQ
Fintech testing questions
Do you test against live payment systems?
We prefer a staging environment with test cards and sandbox accounts from your payment providers. If production testing is needed, we agree rules of engagement first, avoid moving real money, and coordinate anything that could trigger fraud controls.
Can your report be used for PCI DSS?
Yes. Our reports document scope, methodology, dates, findings and retest results, which is what a QSA or your internal assessor looks for under Requirement 11.4. Confirm with your assessor what they need for your validation type.
We are an ICT provider to EU banks. What does DORA mean for us?
Your financial-entity customers must manage ICT third-party risk, and contracts for critical or important functions must include participation in their threat-led penetration testing. Many also ask suppliers for their own recent test evidence. We can test your platform and provide a report and attestation letter you can share under NDA.
Do you test business logic or only technical vulnerabilities?
Both. In fintech the most serious issues are often logic flaws, such as approving your own transfer or exceeding a limit with parallel requests. Testers work through each workflow by hand with test accounts for every role.
Need a pentest for an audit, a customer, or peace of mind?
Tell us what you need tested. You’ll get a fixed-fee proposal with tester-days and timeline stated, usually within a few days of the scoping call.