Strategy and Solutions
Our client was a fast-growing FinTech preparing to launch a mobile payments platform supporting peer-to-peer transfers, digital wallets, and merchant APIs. The product roadmap targeted rapid expansion into card-present and card-not-present flows with issuer tokenization and instant settlement. Because the platform processes cardholder data and authorization tokens, PCI DSS compliance and a demonstrably secure application were non-negotiable prerequisites for partnerships with acquirers, card brands, and banking allies.
The company’s go-to-market was anchored to a funding milestone and a national launch. Security failure would jeopardize onboarding agreements with the acquiring bank and stall investor confidence. The brief to Zymr was direct: perform full-stack security testing, map findings to PCI DSS, drive remediation to closure, and enable a secure launch without slipping the date.
In short, the client needed verifiable assurance that its app, APIs, and payment back end were hardened to withstand real-world attacks and that PCI DSS evidence was complete before the go-live gate.
The engagement began against tight timelines and visible risks across the application and payments stack.
Agile development velocity outpaced formal security testing. Critical flows—device registration, MFA challenges, JWT issuance/refresh, and money-movement APIs—had not undergone structured pen testing aligned to OWASP MASVS and API Top 10. Staging mirrored production in function, not in hardening.
Encryption was in place but not consistently validated. Cardholder data environment (CDE) boundaries were ambiguously documented. Segregation between CDE microservices and general app services was weak, and key management procedures were not captured in auditable SOPs.
Static and SCA scans flagged vulnerable dependencies (e.g., outdated JWT libs), permissive CORS rules, and session timeouts that exceeded policy. Password reset flows leaked reset token lifetime via verbose errors; rate-limiting policies were inconsistent across endpoints.
The funding round and partner marketing were tied to launch. Any PCI DSS failure or critical finding late in the cycle would push the date, risking both capital and market momentum.
Summed up, the client needed to close concrete vulnerabilities, clarify PCI scope and controls, and prove that security would remain intact as the product iterated—without missing a fixed launch window.
Zymr turned security and PCI DSS from a late-stage obstacle into a launch accelerator. The client shipped on schedule, passed audits cleanly, and earned trust with acquirers, card brands, and customers. Security became a product quality signal and a negotiation advantage with partners and investors.
Bottom line: fewer surprises, faster deals, and a security baseline that scales with growth rather than constraining it.
The platform entered the market with verified resilience and clean PCI credentials, enabling partnerships and customer adoption from day one.
Beyond the immediate launch, the company gained a repeatable security posture—controls that run automatically, evidence that stands up to scrutiny, and teams that build securely by default.
Zymr executed a phased, evidence-driven program that combined deep testing, PCI DSS validation, and DevSecOps enablement.
We performed black-box and gray-box penetration testing across mobile apps (iOS/Android), web console, APIs, and payments back end. Techniques included credential stuffing simulations, OAuth/JWT tampering, IDOR mapping, API fuzzing, SSRF exploration against metadata endpoints, and stored/DOM XSS probes in merchant dashboards. We validated device binding and certificate pinning, reviewed jailbreak/root detection, and confirmed secure keystore/Keychain usage for token storage.
Results were triaged by exploitability and business impact. Critical issues included an API endpoint that accepted unsigned JWT on refresh, session fixation via non-rotating auth cookies, and a verbose error revealing partial PAN in a rare recovery path. We issued a remediation plan linking every finding to a PCI DSS control ID, owner, fix pattern, test steps, and acceptance criteria. “Now,” “Next,” and “Later” swim-lanes balanced risk reduction with sprint capacity.
Control Implementation Support (PCI DSS)
We embedded SAST, SCA, and container image scanning into CI/CD; added IaC scanning for Terraform; introduced signed artifacts and SBOM generation. Merge gates blocked builds with critical CVEs; dependency update cadences were automated. A security test harness replayed exploit POCs on every build until fixed.
We built an evidence register mapping artifacts to PCI DSS requirements (policies, diagrams, key ceremonies, access attestations). Mock QSA sessions prepped engineering and operations for auditor interviews. We trained teams on secure coding patterns (e.g., JWT audience/issuer checks, CSRF defenses, rate-limiting with circuit breakers).
Collectively, the solution closed exploitable paths, established durable PCI DSS evidence, and embedded continuous security checks so the product could scale without reintroducing risk.
The platform entered the market with verified resilience and clean PCI credentials, enabling partnerships and customer adoption from day one.
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