Juan Cadima

Application Security Engineer | Backend Systems & Infrastructure

 Core Competencies

  • Vulnerability Analysis
  • IDOR, SSRF, XSS
  • Deserialization
  • Type Juggling
  • Docker escape
  • Threat Modeling (STRIDE / DFD)
  • SAST / DAST / SCA Integration
  • CI/CD & Container Security
  • Linux/Infrastructure Hardening

 Work Experience

March 2024 - Present
DirectDeals/U2Connect

Application Security Engineer | Backend Systems & Infrastructure

  • Led end-to-end incident response for a live production compromise on a self-managed Linux VPS, containing an active cryptominer and PHP web shell. Conducted root-cause analysis (RCA) and implemented permanent hardening (disable_functions, fail2ban, file integrity monitoring) with zero client downtime, producing a full PICERL-based incident writeup.
  • Set up automated security scanning (SAST, SCA, DAST) as part of the CI pipeline, consolidating fragmented security findings into a single developer dashboard.
  • Proactively hardened the infrastructure attack surface across multiple client-facing Laravel deployments (nginx, PHP-FPM, fail2ban), including nginx location-block precedence flaws and overly permissive Redis access that exposed unauthenticated data paths.
  • Designed and implemented secure RESTful APIs and background workers, enforcing strict input validation, parameterized querying, and rate-limiting to mitigate OWASP API Top 10 risks.
  • Engineered internal administrative dashboards with Firebase-integrated authentication with role-based access control and audit logging embedded at the data layer.
  • Leveraged generative AI to accelerate secure code review cycles, translating CVE descriptions into actionable remediation steps and automating the refactoring of vulnerable legacy PHP patterns (e.g., SQLi, XSS) into OWASP-compliant equivalents, reducing manual review effort by ~30%.
Oct 2022 - February 2024
Contractor

Full Stack Developer

  • Built a multilingual custom CMS (Laravel, Livewire) with role-based access control and input validation across all admin-facing forms, reducing admin time by over 30%.
  • Audited and hardened invoice and payment-adjacent workflows during a financial operations overhaul, reducing manual adjustment errors.
  • Maintained and secured multiple e-commerce platforms, addressing performance bottlenecks and mobile responsiveness alongside routine dependency and patch upkeep.
  • Diagnosed and resolved high-priority bugs in a ticketing system, including logic flaws affecting data integrity, improving platform stability.
Oct 2021 - Oct 2022
Ideal Image

Senior Backend Engineer

  • Architected RESTful APIs and Dockerized background workers in a microservices environment with a focus on service isolation, reducing deployment errors and improving development-to-production consistency.
  • Integrated React and Laravel into a cohesive stack, applying secure API contract design (auth boundaries, input schemas) to launch a full-featured application ahead of schedule.
  • Engineered and maintained APIs supporting thousands of daily transactions, enforcing validation and access control at every third-party integration point.
  • Optimized SQL queries and restructured schema to eliminate injection-prone dynamic query patterns while improving data access performance.
Aug 2020 - Oct 2021
NIA Auto Design

Full Stack Developer/Admin

  • Refactored a Laravel application's codebase to modern design patterns, reducing technical debt and shrinking the surface area for logic-layer bugs.
  • Applied security patches on a regular cadence and wrote Python/Bash automation for server backups, building early operational security habits.
  • Automated core e-commerce business logic (invoicing, inventory) and managed payment gateway integrations, handling sensitive transaction data end to end.
  • Deployed and maintained production Linux servers with an ongoing focus on performance and security posture.
June 2018 - July 2020
C&I Studios

Full Stack Developer

  • Designed and developed custom web applications (PHP/Laravel/WordPress, MySQL) with a focus on performance, scalability, and maintainable architecture.
  • Built internal CMS and registration tooling for admin store operations, automating manual data entry and reducing processing errors.
  • Refactored legacy code to modern object-oriented patterns, improving readability and reducing latent bugs.
Feb 2015 - June 2018
Pop Creative Group

Web Developer

  • Developed custom full stack applications (WordPress, Laravel) integrating third-party APIs (YouTube, Stripe, Authorize.net), handling payment data securely.
  • Refactored legacy code to modern object-oriented techniques and led a Magento v2 migration.
  • Managed project timelines and stakeholder requirements while maintaining documentation for existing and new applications.

 Education

  • Florida International University

 Languages

  • English
  • Spanish