Principal Security Engineer

VulnU; Addlestone; Remote; GBP 120,000 - 180,000; Full time

Benefits offered by this job

Equity

Job summary

F5 is seeking a Principal Security Engineer in Addlestone to lead the Security Incident Response Team (SIRT). You will drive incident handling, threat analysis, and security training across products, coordinating with engineering, legal and communications.

The role requires deep expertise in cloud, network and application security, vulnerability management, and secure coding practices, with a proven track record in high-stakes security operations.

Qualifications

• Minimum of 15 years of experience in a technical security role (support/monitoring/consulting).
• Expert understanding of CVE, CVSS, and CERT concepts.
• Strong knowledge of NIST standards and security frameworks.
• Experience with security incident handling processes and methodologies.
• Experience with security advisories, threat intelligence, and vulnerability management.
• Proficient in incident response planning and security content creation.
• Hands-on experience with network security tools and cloud security.

Responsibilities

• Lead and mentor the SIRT team and security engineers.
• Drive incident handling and mitigation options for security incidents.
• Develop and deliver security content and training.
• Maintain and improve incident response plans and playbooks.
• Coordinate with product engineering, legal, comms, and management to publish advisories.
• Document incidents, post-mortems, and remediation actions.
• Provide strategic security analytics metrics and dashboards.

Skills

LAN/WAN ops

Network security

Incident handling

Threat modeling

Secure coding

Python scripting

Cloud security

Vulnerability management

WAF/IPS

Public cloud

Education

BA/BS degree or equivalent

CISSP

GCIH

Public cloud certs

Tools

Web Application Firewalls

Firewalls

IPS/IDS

Job description

# Principal Security EngineerF5 · f5.comCategory: Cloud SecurityLocation: AddlestoneLevel: Staff / Principal## Quality of lifeWhat the posting states. Hover or tap a perk to see the line it came from.* EquityAt F5, we strive to bring a better digital world to life. Our teams empower organizations across the globe to create, secure, and run applications that enhance how we experience our evolving digital world. We are passionate about cybersecurity, from protecting consumers from fraud to enabling companies to focus on innovation. Everything we do centers around people. That means we obsess over how to make the lives of our customers, and their customers, better. And it means we prioritize a diverse F5 community where each individual can thrive.The Principal Security Engineer is a technical security position in the F5 Security Incident Response Team (F5 SIRT). Addressing security issues in F5 products is the responsibility of the F5 Security Incident Response Team (F5 SIRT). The F5 SIRT is a dedicated, global team that manages the receipt, investigation, and public reporting of security vulnerability information that is related to F5 products and networks.The Principal Security Engineer position provides expert security technical leadership for F5 SIRT. This position requires complete Security Knowledge and an expert with regards to security threats, incident handling methodologies and offensive/defensive attack vectors. A Principal Security Engineer follows incident handling procedures to drive mitigation of security incidents and will be called to perform expert attack analysis, configuration suggestions, and potential onsite interaction. A Principal Security Engineer can handle multiple active issues of diverse scope simultaneously while maintaining good communication, particularly written communication to our customers, and accepts ownership of issues until a resolution is delivered or a business as usual state is returned, providing high customer satisfaction. When not engaged in incidents, a Principal Security Engineer will mentor other security related issues, researches emerging threats and both documents and presents their impact on F5 products and services. Advocates every single day for improving the security of F5 products and services.A good candidate has a deep passion for security and a desire to help develop a security mindset in others. The role also requires a strong ability to work with incomplete information and to adapt to changing priorities. PRIMARY RESPONSIBILITIES:Responsible for upholding F5s business code of ethics & for promptly reporting violations of the code or other company policiesManages multiple issues and prioritizes based upon customer and business needs, without directionProvides F5 customers with a consistently high-quality support experienceAssist other Security Engineers with other tasks as required based upon business operation needsEffectively engages supporting escalation personnel, without directionParticipate in weekend support rotationParticipate in tier 2 and tier 3 security supportProvides F5 customers with high-quality support experienceManages multiple issues and prioritizes based upon customer and business needs, without directionEffectively engages supporting escalation personnel, without directionEnsure complete and clear incident documentationMaintain incident documentation, participate in post-mortems, and write incident reports.Continuous research into emerging threats and mitigation optionsIndependently develops and deliver security content and training based on research and testing within the security field and with F5 products to drive security mindset.Perform general security awareness and specific security technology trainingEngages in ongoing training within the security field and with F5 productsFollows processes defined in F5’s Quality Management System (QMS)Work closely with others to develop incident response plansIdentify the gaps between the security incident response process and customers' needs, optimize/improve the workflow/processAct as the technical lead, identify the knowledge/technical skill gaps in the team, develop a training plan for the team, mentor/train other members of the teamIdentify trends and/or common knowledge gaps and ensure they are documented via the KCS Solve LoopEnsure that security-related knowledge is documented within KCS and represent Security within the KCS Evolve Loop, for example RCA feedback into product design & documentationMay lead projects and provide guidance/training to less experienced staff, mentoring.Perform expert threat and vulnerability management, monitoring of CVE, and vendor notificationsEvaluate and execute cross-functional security initiatives across the enterprise.Work with cross-functional Engineering teams to ensure all systems are properly remediated according to our policies and standards.Lead steering committee(s) to analyze vulnerabilities and their impact to assess risk ratingsProvide strategic security analytics metrics and reports.Capable of anticipating future business challenges and crafting security strategies that mitigate those risksProvide security-related metrics for all levels, including executive-level dashboards to demonstrate process effectiveness and remediation across the enterpriseEffectively communicate and document risks related to the vulnerability environment and appropriate levels of urgency to management and engineering staffRepresent Security on organizational projects and ensure adherence to existing security policies and standards.Work closely with Incident Response and Risk Management teams and leverage corporate tools to provide supporting documentation for remediation prioritization and emergency security coverage.Ability to think with a security mindset. The successful candidate has a strong IT background with in-depth knowledge of several key security practice areas: application security, network security, and infrastructure security. Product Security Incident Response Team (PSIRT) and Vulnerability ManagementMonitor and identify security vulnerabilities in F5’s products and Services by tracking internal reports, external researcher submissions, bug bounty programs, and industry threat intelligenceTriage and assess reported vulnerabilities and incidents, determining severity, impact, and prioritization based on risk to customers and systemsCoordinate with Product Engineering, Product Management, Legal, Corporate Communications, and other teams to develop security advisories for security issues.Communicate effectively with stakeholders, disseminating clear security advisories, mitigations, and fix notifications to customers, partners, and the public.Manage interactions with external security researchers, validating vulnerability disclosures, and facilitating recognition or rewards through bug bounty programs when applicable.Document all security incidents, responses, and resolutions to ensure compliance, support audits, and drive process improvements.Develop, maintain, and update security/Quarterly Security Notification (QSN) playbooks, and workflows to optimize vulnerability management and incident response processes.Engage with the broader security community, participating in industry forums, sharing threat intelligence, and collaborating with other PSIRTs to stay ahead of emerging threats (CISA, FIRST, VINCE, etc). Customer Security Incident ResponseProvide incident handling and drive both attack analysis and mitigation optionsParticipate in tier 2 and tier 3 security supportFollows processes defined in F5’s Quality Management System (QMS)Mentoring Security SRs to resolution - Proactively monitors Security Service Request (SR) with long Time to Resolution (TTR)Working with F5 SIRT Specialists to handle ESRP casesMaintain incident documentation, participate in post-mortems, and write incident reports.Working with SR Security Engineers on post-mortem for ESRP incidentsTracking attack trends and threat intelligence from different sourcesMonitors security issues in order to identify and act upon them as they occur – Active MentoringRunning workshops to help F5 SIRT Specialists build hands-on experience in a lab environment in order to better prepare for dealing with attacks in the real environment – With Sr. Sec EngSimulating a typical customer network environment (in terms of versions, modules, network devices), running different attacks, documenting the security incident response plan, and exercising itWork closely with others to develop incident response plans Building Security Mindset - Security EvangelismRunning regional F5 SIRT meetingsHandling reactive mentor questions on Security from F5 SIRT Specialists and NSEs – Monitor F5 SIRT emailCreating security presentations for a wide audienceEngages in ongoing training within the security field and with F5 productsMay lead projects and provide guidance/training to less experienced staff and mentoring.Evaluate and execute cross-functional security initiatives across the enterprise.Work with cross-functional Engineering teams to ensure all systems are properly remediated according to our policies and standards. QUALIFICATIONS:Minimum of 15 years of experience in a technical security role such as support, monitoring or consulting (e.g. pen testing) working with relevant technologiesInformation security subject matter expertExpert understanding of industry standards such as CVE, CPE, and CVSSStrong understanding of security frameworks and NIST standardsAppropriate security-based qualification; CISSP, GCIH (or demonstrated skills and ability to obtain certification) – more than one certification preferred.Public cloud certifications (or demonstrated skills and ability to obtain certification)Expert experience with security incident handling processes, procedures and methodologies.Expert technical experience with identifying and mitigating a breadth of attacks such as DDoS, web application, DNS, and other network attacks.Expert knowledge of common security vulnerabilities and the ability to judge their severityExpert experience with working security incidents at corporate production environmentsExperience working with network and packet analysis toolsBA/BS degree or equivalent experienceExpert knowledge with Web Application Firewalls, Firewalls and IPS/IDSExpert experience with network vulnerability scannersExpert OS hardening and security best practicesKnowledge of common Malware types and infection vectorsExpert knowledge in threat modeling, secure architecture, secure coding practices, and security testing. KNOWLEDGE, SKILLS AND ABILITIESHands on technical experience with and very knowledgeable on LAN/WAN operations, and/or networking hardware requiredCVE and CERT experienceExpert knowledge of security offensive/defensive techniques and methodologies.Expert understanding of security attack/defense methodologies (e.g. DNS, network TCP/IP, SSL and HTTP)Expert understanding and working knowledge of TCP/IP, SSL, DNS, HTTP, and common protocols.Coding experience – having, in addition to proficiency in Python, knowledge in other scripting languagesUnderstanding of the underlying mechanisms for security vulnerabilities at a code and assembly level, e.g. buffer overflows, input sanitisationKnowledge of network and security monitoring toolsFamiliarity with load balancers, WAF’s and common network architecturesWorking knowledge of standard UNIX/Linux command line toolsHands-on technical experience with public clouds (e.g. AWS, Azure, or GCP), and container-based deployments and orchestration tools (e.g. Kubernetes, Docker, Terraform, and Ansible)Knowledge of microservice architecture, modern application architecture, and API securityAbility to generate new training and knowledge sharing content via various delivery methods Able to work with moderate supervisionProven track record in a team environmentAnalytical thinker with strong attention to detailContinue reading the full posting on F5's careers page →