Principal Security Engineer, Detection & Response

Circle is an internet financial platform company building digital asset, payment, and programmable blockchain infrastructure. The Principal Security Engineer will lead security detection and response across blockchain and custody environments, cloud-native infrastructure, and AI tooling, while responding to incidents and advancing security operations capabilities.

Responsibilities:

• Proactively identify and respond to emerging security threats across cloud, endpoint, blockchain, and AI surfaces
• Build detection and response capability for blockchain and crypto-native threats: on-chain anomalies, custody-vault interactions, wallet abuse, smart contract exploitation, and protocol-level attackers targeting USDC and Circle's blockchain products
• Develop detection coverage for cloud-native attacks across AWS + EKS: IAM compromise, identity federation abuse, lateral movement in containerized workloads, runtime exploitation, and misconfiguration drift
• Extend detection for AI-specific risks: shadow AI adoption, unauthorized AI integrations, agentic workflows and MCP/tool abuse, and AI-driven credential exposure
• Advance deployment of AI to the SOC function including detection triage, enrichment, and analyst-acceleration workflows
• Develop plans to manage and maintain core tooling, such as SIEM and Orchestration platforms
• Identify gaps in our infrastructure, and work with business partners to gain visibility through logging and detection
• Lead and respond to incidents and collaborate across teams to investigate and resolve
• Develop detection techniques to identify anomalous behaviors and attacks across the environment
• Provide security guidance to various organizations throughout the company
• Support broader security team projects such as threat modeling, vulnerability scanning, audits, and custom tool building
• Take on-call shifts (every 3rd week and occasional weekend)

Requirements:

• Strong ability to work collaboratively across teams during high-stress situations, which sometimes involves after hours work
• Ability to manage multiple competing priorities and use good judgment to establish order of priorities on the fly
• Self-motivated and creative problem-solver able to work independently with minimal guidance
• Experience/familiarity with Slack, Apple macOS, and GSuite
• 10+ years of experience in detection, response, or security engineering
• 3+ years of experience commanding security incidents, especially those involving engineering
• Deep cloud security knowledge in AWS environments: IAM, identity federation, KMS, EKS/container attack patterns, runtime exploitation, and CSPM tooling (e.g., Wiz)
• Working knowledge of blockchain and crypto-native threats: wallet and custody attack patterns, on-chain monitoring, protocol-level risks, and smart contract abuse
• Hands-on experience using AI tooling both to accelerate work and to address threats, coupled with a strong understanding of the organizational risks AI introduces shadow AI, agentic workflows, MCP/tool integrations, and strategies to defend against them
• Extensive knowledge of SIEM, Case Management, and SOAR solutions (e.g., Panther, Tines)
• Knowledge of operating systems, file systems, and memory on macOS
• Programming experience in Python, Golang, or similar programming languages
• Experience with building Detections As Code
• View Security Detection & Response as a data and engineering problem
• Exude positivity
• Aren't afraid to share your ideas
• Meet problems head-on and view them as opportunities
• Are self-reliant and motivated
• Communicate fearlessly
• Some exposure to GCP or OCI is preferred
• Direct experience defending blockchain, custody, or DeFi infrastructure is strongly preferred