Senior Threat Researcher (UK)

About Us Sophos is a cybersecurity leader defending 600,000 organizations globally with an AI-driven platform and expert-led services. Sophos meets organizations wherever they are in their security maturity and grows with them to defeat cyberattacks. Its solutions combine machine learning, automation, and real-time threat intelligence with frontline human expertise from Sophos X-Ops to deliver advanced, 24/7 threat monitoring, detection, and response. Sophos offers industry-leading managed detection and response (MDR) alongside a comprehensive portfolio of cybersecurity technologies — including endpoint, network, email, and cloud security, extended detection and response (XDR), identity threat detection and response (ITDR), and next-gen SIEM. Together with expert advisory services, these capabilities help organizations proactively reduce risk and respond faster, with the visibility and scalability needed to stay ahead of evolving threats. Sophos goes to market with a global partner ecosystem, including Managed Service Providers (MSPs), Managed Security Service Providers (MSSPs), resellers and distributors, marketplace integrations, and cyber risk partners, giving organizations the flexibility to choose trusted relationships when securing their business. Sophos is headquartered in Oxford, U.K. More information is available at www.sophos.com.
Role Summary We are seeking a detail-oriented and technically skilled Detection Engineer to join our X-OPS team. In this role, you will be responsible for analyzing advanced security threats—ranging from malware to complex web attacks—and translating threat intelligence into high-fidelity detections across our platform. Your work will help ensure our analysts and clients receive highly accurate, actionable alerts with minimal noise. You will leverage data from over 40 third-party and internal sources, partner with our CTU Threat Intelligence team, and use a range of scripting and automation tools to strengthen detection capabilities. The ideal candidate is a hands-on security practitioner with a deep understanding of endpoint behavior, cloud behavior, and detection development who thrives in fast-paced, technical environments.

What You Will Do

• Develop countermeasures to detect advanced threats based on research and intelligence from the CTU team.
• Analyze endpoint behaviors and logs to design detections using multi-source telemetry.
• Continuously refine and monitor detection rules to optimize the signal-to-noise ratio for alerts.
• Research and implement alert handling for new device ingestions, ensuring high-value signal delivery.
• Leverage internal tooling to distinguish native from standard integrations for detection accuracy.
• Collaborate on the development of internal tools, automation, and detection infrastructure.
• Act as a subject matter expert across departments including Product Management, Marketing, and Labs Research.

What You Will Bring

• Strong passion for cybersecurity research and the ability to quickly learn emerging technologies.
• Hands-on experience in scripting languages (PowerShell, Bash, Python) and use of Python data science libraries (e.g., NumPy, Pandas, Matplotlib).
• Knowledge of CI/CD pipelines, testing frameworks, and automation principles.
• Proficiency in analyzing logs from firewalls, proxies, and security infrastructure to identify anomalies.
• Familiarity with event logs, traffic pattern anomalies, and threat hunting methodologies.
• Strong understanding of endpoint detection, Linux/Unix and Windows OS internals, vulnerability identification, and workflow automation.
• Forensic analysis of memory and disk images across various OS and file system types is a plus.
• Experience in malware analysis, including static/dynamic techniques and reverse engineering (IA32/64, ARM binaries) is a plus.
• Experience with event correlation and incident reconstruction using log data is a plus.
• Network traffic analysis skills, including identification of anomalous or malicious traits is a plus.
• Solid grasp of database querying, systems architecture, and process automation for operational improvements is a nice to have.

Ready to Join Us? At Sophos, we believe in the power of diverse perspectives to fuel innovation. Research shows that candidates sometimes hesitate to apply if they don't check every box in a job description. We challenge that notion. Your unique experiences and skills might be exactly what we need to enhance our team. Don't let a checklist hold you back – we encourage you to apply. What's Great About Sophos? · Sophos operates a remote-first working model, making remote work the primary option for most employees. However, some roles may necessitate a hybrid approach. While we are a remote first organization, applicants must have legal authorization to work in the jurisdiction where the position is posted, without requiring employer sponsorship. · Our people – we innovate and create, all of which are accompanied by a great sense of fun and team spirit · Employee-led diversity and inclusion networks that build community and provide education and advocacy · Annual charity and fundraising initiatives and volunteer days for employees to support local communities · Global employee sustainability initiatives to reduce our environmental footprint · Global fitness and trivia competitions to keep our bodies and minds sharp · Global wellbeing days for employees to relax and recharge · Monthly wellbeing webinars and training to support employee health and wellbeing Our Commitment To You We’re proud of the diverse and inclusive environment we have at Sophos, and we’re committed to ensuring equality of opportunity. We believe that diversity, combined with excellence, builds a better Sophos, so we encourage applicants who can contribute to the diversity of our team. All applicants will be treated in a fair and equal manner and in accordance with the law regardless of gender, sex, gender reassignment, marital status, race, religion or belief, color, age, military veteran status, disability, pregnancy, maternity or sexual orientation. We want to give you every opportunity to show us your best self, so if there are any adjustments we could make to the recruitment and selection process to support you, please let us know. Data Protection If you choose to explore an opportunity, and subsequently share your CV or other personal details with Sophos, these details will be held by Sophos for 12 months in accordance with our Privacy Policy and used by our recruitment team to contact you regarding this or other relevant opportunities at Sophos. If you would like Sophos to delete or update your details at any time, please follow the steps set out in the Privacy Policy describing your individual rights. For more information on Sophos’ data protection practices, please consult our Privacy Policy Cybersecurity as a Service Delivered | Sophos