The real cost of a broken login
Authentication is the front door of your fintech application. If the front door is weak, all the complex internal security controls—database encryption, VPC isolation, strict API routing—are completely useless. If an attacker can log into your application as a legitimate user, your backend will gladly process their fraudulent transactions.
Developers often treat authentication as a solved problem. They pull a generic library from GitHub, wire it up to a database, and assume it works. But fintech authentication is not generic. You are dealing with biometric device binding, One-Time Passwords (OTPs) sent via SMS, multi-factor authentication (MFA) fallback paths, and strict regulatory rules around session expiration.
If you make one mistake in the state machine of a password reset flow, an attacker will hijack thousands of customer accounts. We perform deep, manual reviews of your entire authentication and session lifecycle to ensure your front door is bulletproof.
How strong is your authentication chain, really? Book a manual security audit today.
Book an Auth Security AuditWhat we review
Authentication links registration, verification, session creation, token refresh, recovery, and logout. We test the full chain and show the exact step that lets an unauthorised user through.
Login & registration
Credential validation, account enumeration, brute-force protection, and the registration flow that determines what identity claims your system trusts from the start.
Password recovery
The most dangerous flow in any fintech app. We test reset token generation, delivery channel security, token expiration, and whether recovery can be chained into session upgrade or email change.
OTP & 2FA
OTP brute-force resistance, code reuse, timing attacks, delivery fallback paths, and whether 2FA can be bypassed through alternative authentication flows.
Token lifecycle
JWT signing, access token expiration, refresh token rotation, and what happens when a session should be dead but the token is still alive.
Session management
Concurrent session handling, session fixation, privilege changes during active sessions, and whether logout actually invalidates everything it should.
Permission boundaries
Role transitions, privilege escalation paths, and the gap between what the UI shows a user and what the API lets them do.
Our methodology for destroying auth flows
We build a complete state machine of your authentication logic. We map every state a user can be in: Unauthenticated, Partially Authenticated, Fully Authenticated, Password Resetting, Account Locked. Then we actively force the system into illegal states.
1. Brute forcing and enumeration
We test if your API reveals which email addresses or phone numbers are registered in your database. This is called account enumeration. We check if your login endpoints and OTP verification endpoints enforce strict rate limiting. If you allow us to guess a 4-digit OTP 10,000 times without locking the account, your MFA is effectively useless.
2. Chaining recovery flows
Password recovery is notoriously hard to build securely. We request a password reset link. We use it. But before we submit the new password, we check if the server already issued us an active session token. We check if the reset token can be reused. We check if requesting a second reset token invalidates the first one. We chain these small logic errors together to force a full account takeover.
3. Token tampering
If you use JSON Web Tokens (JWT), we manipulate them. We change the algorithm header to `None`. We attempt to sign the token with your public key instead of your private key. We modify the user ID inside the token payload to see if your backend blindly trusts it. We steal the token, send it from a different IP address, and verify if you implement strict session binding.
Session upgrade via password recovery
Password recovery flow issued a fully authenticated session token - without requiring the new password to be set first. An attacker with access to the recovery link could skip password creation entirely and land in the account with full privileges.
Does your application handle biometric logins safely? Find out before it costs you.
Book a Security ReviewWhat to prepare for an authentication review
Provide accounts for each role, identity provider details, token formats, session rules, and a map of registration, login, MFA, recovery, device change, and logout. Include support and admin paths that can reset access or act on a customer account.
The review tests account access and session control. It does not replace full application authorization testing. If users can access records, approve transfers, or act across tenants after login, add web application testing or API security testing.
Evidence your engineers receive
Each confirmed issue includes the affected flow, exact account state required to trigger it, request and response evidence, and direct business impact. We provide exact fixes tied to the control that failed.
Each confirmed issue includes the affected flow, the exact account state required to trigger it, request and response evidence, and the direct business impact. We provide exact fixes tied to the control that failed. If your JWT implementation is flawed, we provide the correct library configuration for your specific framework (Node.js, Django, Spring Boot).
The report separates pure login flaws (handled by identity teams) from authorization flaws (handled by product teams) so the right engineers can take immediate ownership of the fixes.
Why auth reviews need fintech-specific expertise
Generic auth testing checks for OWASP basics. In fintech, the stakes are different. A broken session in a blog platform is an inconvenience. A broken session in a payments app is a direct financial loss - for your users and for your company.
We test with the context of how Nigerian fintech products actually work: BVN-linked identity, mobile-first auth flows, OTP-heavy verification, and the regulatory requirement to protect customer funds and personal data. We understand the edge cases when users change devices, lose their SIM cards, or attempt to bind multiple accounts to a single identity.
Secure your users. Secure your transactions. Secure your business.
Get a Quick Security CheckRelated services and resources
Authentication security is tightly connected to API security testing (where authorization enforcement is validated at the endpoint level) and broader penetration testing. For a developer-oriented reference, our fintech security checklist covers OTP rate limiting, session expiration, and recovery flow best practices.
Frequently asked questions
Do you test biometric authentication?
We test the software path around biometric authentication: device binding, enrolment, fallback, recovery, session creation, and server-side approval. Hardware assurance comes from the device and biometric platform vendor.
What about third-party auth providers?
We review how your application integrates with identity providers - Google, Apple, BVN verification services. The handoff between your app and the provider is where configuration mistakes create exploitable gaps.
We use JWTs. Is that enough?
JWTs are a format, not a security guarantee. We check signing algorithm enforcement, token expiration handling, claim validation, and whether your backend actually verifies tokens on every request - not just at login.
How do you test OTP security?
We test OTP generation strength, delivery channel security, brute-force protection, timing attacks, code reuse, and the fallback paths when OTP delivery fails. We also check if OTP can be bypassed entirely through alternative flows.