Staff Application Security Engineer

Overview Staff Application Security Engineer role at LEDN. LEDN is a global financial services company built for digital assets, supporting the democratization of access to the global economy through its suite of lending, savings, and trading products. The Opportunity We are seeking a full-time Staff Application Security Engineer with deep expertise in Application Security, Identity & Access Management, and Confidential Computing to strengthen the security of our Bitcoin-backed loan platform. This is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. You will: Work across JavaScript/TypeScript services, AWS serverless stack (Lambda, API Gateway, Cognito, SNS, SQS), MongoDB and Kubernetes microservices. Evolve our authentication layer toward modern, phishing-resistant approaches. Design and operate AWS Nitro Enclaves to protect critical data and cryptographic operations in isolated, verifiable environments. Lead both tactical improvements and long-term strategy for securing applications and authentication systems. Responsibilities Application 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 MFA solutions (WebAuthn, passkeys, hardware tokens); collaborate with Product to align usability, compliance, and security in authentication flows; define secure 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 into enclave environments; ensure compliance, auditability, and resilience of enclave workloads. Additional Security Domains: Harden AWS services 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. Prerequisites / What You Bring To Ledn 10 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; remediation of vulnerabilities identified in penetration tests. Strong communication and collaboration skills to influence engineering and product teams. Nice To Haves Familiarity 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 Fit & The Ideal Candidate We’re looking for a leader who thrives in a startup or tech environment and embodies our values: act with integrity, own it, have a passion for progress, and lead with empathy. Have a passion for progress by being adaptable and resilient, and comfortable navigating ambiguity in a high-growth, fast-paced environment. Have a builder’s mindset, excited to create, iterate, and scale IS practices; be a collaborative partner who can influence across functions and cultures with empathy and clarity; demonstrate integrity and accountability in handling confidential information. Experience working in a remote environment. Benefits & What We Provide Comprehensive, best-in-class total rewards package that starts on your first day; a competitive PTO package; ownership in the company through shared equity. Remote work option: work remotely anywhere in the world for up to 180 days (subject to restrictions). A purpose-driven career and a culture that removes barriers so you love what you do. We are an equal opportunity employer committed to inclusivity and diversity. To request accommodations at any stage of the recruitment process, please contact the Ledn team confidentially. Ledn’s working environment is global and remote-first. Due to high volume of applications, only qualified applicants will be contacted. Shortlisted candidates may be asked to submit a short video response and we may review publicly available social media activity relevant to the role. No agencies or recruiters, please. #J-18808-Ljbffr