Staff Application Security Engineer

OverviewStaff Application Security Engineer at LEDN. Ledn is a global financial services company built for digital assets, offering lending, savings and trading products to digital asset holders in over 150 countries. The role focuses on strengthening the security of our Bitcoin-backed loan platform and authentication systems, with hands-on engineering across our JavaScript/TypeScript services, AWS serverless stack, MongoDB, and Kubernetes. This is a hands-on engineering role with direct impact on product security, infrastructure security, and customer trust. ResponsibilitiesLead 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. 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. Design enclave-based architectures to isolate and protect sensitive workloads using AWS Nitro Enclaves; integrate with KMS and secure APIs; migrate high-value operations into enclave environments; ensure compliance and auditability. 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. Qualifications10 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 and understanding of software supply chain. Deep understanding of Linux internals. Remediate vulnerabilities identified in penetration test reports. Strong communication and collaboration skills, able to influence engineering and product teams. Nice To HaveFamiliarity 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 FitLead with integrity, adaptability, and empathy; thrive in startup or tech environments. Builder's mindset, excited to create, iterate, and scale information security practices. Collaborative, able to influence across functions and cultures with clarity. Maintain confidentiality and accountability in handling sensitive information across diverse contexts. Experience working in a remote environment. A Taste Of What We ProvideGrowth opportunities at Ledn, a leading digital asset company. Comprehensive total rewards package starting from day one. Competitive PTO and remote-first policy; work remotely anywhere in the world for up to 180 days (subject to restrictions). Equity ownership in the company; employees are stakeholders in the future of digital economy. Purpose-driven work; we remove barriers so you love what you do. Equal opportunity employer; inclusive and diverse workforce. Accommodation requests accepted via email for recruitment process (confidentially). Please note that due to high volume of applications, only qualifying 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. We do not accept unsolicited agency resumes. #J-18808-Ljbffr