Staff Application Security Engineer

OverviewStaff Application Security Engineer at LEDN. Ledn is a global financial services company built for digital assets, helping Bitcoin holders and supporting the future of wealth. LEDN offers lending, savings and trading products to digital asset holders in over 150 countries. LEDN values integrity, owning responsibilities, progress, and empathy, and aims to democratize access to the global economy through its products and services. ResponsibilitiesApplication Security: Lead secure design and code reviews across engineering teams. Define and enforce secure coding practices for JavaScript/TypeScript services. Automate vulnerability detection (SAST, SCA, DAST) within CI/CD. Conduct threat modeling and risk assessments for new features. Partner with engineers to remediate vulnerabilities and improve secure development practices. Authentication & Identity: Own the roadmap for authentication and identity across customer and internal applications. Enhance Cognito-based identity architecture with stronger, phishing-resistant MFA solutions (e.g., WebAuthn, passkeys, hardware tokens). Collaborate with Product to align usability, compliance, and security in authentication flows. Define secure approaches to session management, device trust, and account recovery. Confidential Computing (AWS Nitro Enclaves): Design enclave-based architectures to isolate and protect sensitive workloads. Integrate Nitro Enclaves with KMS and secure APIs. Migrate high-value operations (e.g., cryptographic and financial processes) into enclave environments. Ensure compliance, auditability, and resilience of enclave workloads. Additional Security Domains: Harden AWS services (Lambda, API Gateway, SQS, SNS) with least-privilege IAM and secure key management. Improve Kubernetes security posture (RBAC, pod security, image scanning, runtime monitoring). Deploy and operate a SIEM framework; develop detection rules, dashboards, and incident playbooks. Support compliance initiatives (SOC 2, ISO 27001) with security controls and documentation. What You Bring To Ledn10 years minimum of proven experience in Application Security with a focus on web and cloud-native applications. Strong knowledge of JavaScript/TypeScript/Golang/Python and modern web vulnerabilities (OWASP Top 10, auth bypasses, business logic flaws). Expertise with AWS security best practices, particularly in serverless architectures. Hands-on experience with AWS Nitro Enclaves for confidential computing. Deep understanding of authentication and authorization standards (OAuth2, OIDC, WebAuthn, FIDO2). Practical experience with Cognito / Auth0 (MFA, custom flows, secure session handling). Background in SIEM design and log correlation across cloud and application layers. Familiarity with Kubernetes security (RBAC, pod security, admission controls, image scanning). Experience with Secure Code Review. Understanding of software supply chain. Deep understanding of Linux internals. Remediate vulnerabilities identified in the penetration test report. Strong communication and collaboration skills, able to influence engineering and product teams. Nice To HavesFamiliarity with Bitcoin custody and key management practices. Knowledge of Infrastructure as Code security (Terraform, AWS CDK). Prior work on user-facing security features such as passwordless authentication, recovery flows, or device trust. Culture & FitWe’re looking for more than just operational excellence — we want a leader who thrives in the startup or tech environment and embodies our values. The ideal candidate will be adaptable, resilient, and comfortable navigating ambiguity in a high-growth, fast-paced environment. Have a builder's mindset, enjoy creating, iterating, and scaling IS practices. Be a collaborative partner who can influence across functions and cultures with empathy and clarity. Demonstrate integrity and accountability, especially in managing confidential information across diverse legal and cultural contexts. Experience working in a remote environment. A Taste Of What We ProvideGrowth opportunities as LEDN is a leading digital asset company. Comprehensive total rewards package that starts on day one. Competitive PTO package and ownership in the company via equity. Remote work flexibility up to 180 days per year (subject to restrictions). EEO & Recruitment NotesWe are an equal opportunity employer and value inclusivity, diversity, and the success that comes from diversity. Requests for accommodation during recruitment will be addressed confidentially. Ledn is a remote-first team with global distribution; candidacy may involve a short video response and review of publicly available information relevant to the role. No agencies or recruiters; unsolicited resumes are not accepted. Location & ApplicationRio Branco, Acre, Brazil (remote-friendly in certain arrangements). Referrals may increase interview chances. #J-18808-Ljbffr