{"id":3460939,"url":"https://alion.io/job/f5-principal-security-engineer","title":"Principal Security Engineer","company":{"id":5759,"name":"F5","domain":"f5.com","url":"https://alion.io/company/ffive","size_band":"1001-5000","is_staffing_agency":false,"employer_type":"direct","is_intermediary":false,"listed_via":null,"ats_vendor":"Workday","truth_index":{"grade":"B","score":84,"open_postings":24,"ghost_share":0,"stale_share":0.625,"repost_share":0,"time_to_fill_p50_days":43,"computed_at":"2026-10-29T05:49:05Z"}},"role":"Security","role_family":"Security","seniority":"lead","employment_type":"full_time","work_mode":"hybrid","remote_scope":null,"remote_scope_basis":null,"remote_working_hours":null,"hiring_geo_confidence":"structured","locations":["Addlestone, United Kingdom"],"countries":["GB"],"hiring_countries":[],"hiring_countries_total":0,"salary":null,"salary_estimate":{"min_usd":108000,"max_usd":191000,"period":"year","method":"role_seniority_country_remote_cell","sample_n":28},"experience_years_min":15,"visa_sponsorship":false,"relocation_package":false,"has_equity":false,"technologies":[{"name":"Ansible","optional":false},{"name":"AWS","optional":false},{"name":"Azure","optional":false},{"name":"CVE","optional":false},{"name":"CVSS","optional":false},{"name":"DNS","optional":false},{"name":"Docker","optional":false},{"name":"GCP","optional":false},{"name":"Kubernetes","optional":false},{"name":"Linux","optional":false},{"name":"Python","optional":false},{"name":"TCP/IP","optional":false},{"name":"Terraform","optional":false},{"name":"Threat Modeling","optional":false},{"name":"Unix","optional":false}],"status":"live","first_seen_at":"2026-10-29T13:51:52Z","employer_posted_date":"2026-10-29","last_verified_at":"2026-10-30T00:42:52Z","board_verified":true,"closed_at":null,"days_open":0,"trust":{"level":"ok","repost_count":null,"flags":[],"days_open":0},"description":"At 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. \nEverything 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.\nThe 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.\nThe 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.\nA 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.\nPRIMARY RESPONSIBILITIES:\nResponsible for upholding F5s business code of ethics & for promptly reporting violations of the code or other company policies\nManages multiple issues and prioritizes based upon customer and business needs, without direction\nProvides F5 customers with a consistently high-quality support experience\nAssist other Security Engineers with other tasks as required based upon business operation needs\nEffectively engages supporting escalation personnel, without direction\nParticipate in weekend support rotation\nParticipate in tier 2 and tier 3 security support\nProvides F5 customers with high-quality support experience\nManages multiple issues and prioritizes based upon customer and business needs, without direction\nEffectively engages supporting escalation personnel, without direction\nEnsure complete and clear incident documentation\nMaintain incident documentation, participate in post-mortems, and write incident reports.\nContinuous research into emerging threats and mitigation options\nIndependently develops and deliver security content and training based on research and testing within the security field and with F5 products to drive security mindset.\nPerform general security awareness and specific security technology training\nEngages in ongoing training within the security field and with F5 products\nFollows processes defined in F5’s Quality Management System (QMS)\nWork closely with others to develop incident response plans\nIdentify the gaps between the security incident response process and customers' needs, optimize/improve the workflow/process\nAct 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 team\nIdentify trends and/or common knowledge gaps and ensure they are documented via the KCS Solve Loop\nEnsure that security-related knowledge is documented within KCS and represent Security within the KCS Evolve Loop, for example RCA feedback into product design & documentation\nMay lead projects and provide guidance/training to less experienced staff, mentoring.\nPerform expert threat and vulnerability management, monitoring of CVE, and vendor notifications\nEvaluate and execute cross-functional security initiatives across the enterprise.\nWork with cross-functional Engineering teams to ensure all systems are properly remediated according to our policies and standards.\nLead steering committee(s) to analyze vulnerabilities and their impact to assess risk ratings\nProvide strategic security analytics metrics and reports.\nCapable of anticipating future business challenges and crafting security strategies that mitigate those risks\nProvide security-related metrics for all levels, including executive-level dashboards to demonstrate process effectiveness and remediation across the enterprise\nEffectively communicate and document risks related to the vulnerability environment and appropriate levels of urgency to management and engineering staff\nRepresent Security on organizational projects and ensure adherence to existing security policies and standards.\nWork closely with Incident Response and Risk Management teams and leverage corporate tools to provide supporting documentation for remediation prioritization and emergency security coverage.\nAbility 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.\nProduct Security Incident Response Team (PSIRT) and Vulnerability Management\nMonitor and identify security vulnerabilities in F5’s products and Services by tracking internal reports, external researcher submissions, bug bounty programs, and industry threat intelligence\nTriage and assess reported vulnerabilities and incidents, determining severity, impact, and prioritization based on risk to customers and systems\nCoordinate with Product Engineering, Product Management, Legal, Corporate Communications, and other teams to develop security advisories for security issues.\nCommunicate effectively with stakeholders, disseminating clear security advisories, mitigations, and fix notifications to customers, partners, and the public.\nManage interactions with external security researchers, validating vulnerability disclosures, and facilitating recognition or rewards through bug bounty programs when applicable.\nDocument all security incidents, responses, and resolutions to ensure compliance, support audits, and drive process improvements.\nDevelop, maintain, and update security/Quarterly Security Notification (QSN) playbooks, and workflows to optimize vulnerability management and incident response processes.\nEngage 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).\n\nCustomer Security Incident Response\nProvide incident handling and drive both attack analysis and mitigation options\nParticipate in tier 2 and tier 3 security support\nFollows processes defined in F5’s Quality Management System (QMS)\nMentoring Security SRs to resolution - Proactively monitors Security Service Request (SR) with long Time to Resolution (TTR)\nWorking with F5 SIRT Specialists to handle ESRP cases\nMaintain incident documentation, participate in post-mortems, and write incident reports.\nWorking with SR Security Engineers on post-mortem for ESRP incidents\nTracking attack trends and threat intelligence from different sources\nMonitors security issues in order to identify and act upon them as they occur - Active Mentoring\nRunning 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 Eng\nSimulating a typical customer network environment (in terms of versions, modules, network devices), running different attacks, documenting the security incident response plan, and exercising it\nWork closely with others to develop incident response plans\nBuilding Security Mindset - Security Evangelism\nRunning regional F5 SIRT meetings\nHandling reactive mentor questions on Security from F5 SIRT Specialists and NSEs - Monitor F5 SIRT email\nCreating security presentations for a wide audience\nEngages in ongoing training within the security field and with F5 products\nMay lead projects and provide guidance/training to less experienced staff and mentoring.\nEvaluate and execute cross-functional security initiatives across the enterprise.\nWork with cross-functional Engineering teams to ensure all systems are properly remediated according to our policies and standards.\nQUALIFICATIONS:\nMinimum of 15 years of experience in a technical security role such as support, monitoring or consulting (e.g. pen testing) working with relevant technologies\nInformation security subject matter expert\nExpert understanding of industry standards such as CVE, CPE, and CVSS\nStrong understanding of security frameworks and NIST standards\nAppropriate security-based qualification; CISSP, GCIH (or demonstrated skills and ability to obtain certification) - more than one certification preferred.\nPublic cloud certifications (or demonstrated skills and ability to obtain certification)\nExpert experience with security incident handling processes, procedures and methodologies.\nExpert technical experience with identifying and mitigating a breadth of attacks such as DDoS, web application, DNS, and other network attacks.\nExpert knowledge of common security vulnerabilities and the ability to judge their severity\nExpert experience with working security incidents at corporate production environments\nExperience working with network and packet analysis tools\nBA/BS degree or equivalent experience\nExpert knowledge with Web Application Firewalls, Firewalls and IPS/IDS\nExpert experience with network vulnerability scanners\nExpert OS hardening and security best practices\nKnowledge of common Malware types and infection vectors\nExpert knowledge in threat modeling, secure architecture, secure coding practices, and security testing.\nKNOWLEDGE, SKILLS AND ABILITIES\nHands on technical experience with and very knowledgeable on LAN/WAN operations, and/or networking hardware required\nCVE and CERT experience\nExpert knowledge of security offensive/defensive techniques and methodologies.\nExpert understanding of security attack/defense methodologies (e.g. DNS, network TCP/IP, SSL and HTTP)\nExpert understanding and working knowledge of TCP/IP, SSL, DNS, HTTP, and common protocols.\nCoding experience - having, in addition to proficiency in Python, knowledge in other scripting languages\nUnderstanding of the underlying mechanisms for security vulnerabilities at a code and assembly level, e.g. buffer overflows, input sanitisation\nKnowledge of network and security monitoring tools\nFamiliarity with load balancers, WAF’s and common network architectures\nWorking knowledge of standard UNIX/Linux command line tools\nHands-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)\nKnowledge of microservice architecture, modern application architecture, and API security\nAbility to generate new training and knowledge sharing content via various delivery methods \nAble to work with moderate supervision\nProven track record in a team environment\nAnalytical thinker with strong attention to detail\nMust be able to read, write, and speak English fluently, including technical concepts and terminology.\nMust be able to relay technical inf...","description_format":"text","description_chars":14342,"description_truncated":true,"requirements":{"experience_years_min":15,"management_years_min":null,"team_size_min":null,"manages_managers":false,"education":{"level":"phd","optional":false},"security_clearance":false,"languages":[{"language":"English","level":"Advanced (C1)","optional":false}]},"benefits":[],"hiring_locations":[{"name":"United Kingdom","iso":"GB","kind":"country"}],"hiring_excludes":[],"relocation_offered":false,"industries":["Network Security","Application Security","Web Security & DDoS Protection"],"lifecycle":[{"event":"open","at":"2026-10-29T13:51:52Z"}],"visa":[],"liveness":{"score":86,"band":"hot","label":"Hiring now","p_open":1,"p_active":0.86,"p_room":1,"age_days":0,"expected_fill_days":43,"reasons":["conf:4","win:early","comp:brand"],"computed_at":"2026-10-30T05:11:35Z"},"pay":null,"html_url":"https://alion.io/job/f5-principal-security-engineer","json_url":"https://alion.io/job/f5-principal-security-engineer.json","meta":{"generated_at":"2026-10-30T05:11:35Z","cache_seconds":300,"methodology":"https://alion.io/methodology","terms":"https://alion.io/terms","contact":"https://alion.io/contact","api":"https://alion.io/developers","about":"Alion is a live layer of people, companies and AI agents: who they are, whether they are real and active right now, what they do and how to work with them, readable by people and by agents and paid per call.","catalog":"https://alion.io/catalog.json","usage":{"tier":"crawler_verified","counted_by":"address","units_charged":1,"used_today":7257,"day_limit":null,"remaining_today":null,"minute_limit":300,"resets_at":"2026-10-31T00:00:00Z"}},"offers":[{"id":"company.slices","title":"One company in depth, by slice","status":"live","price":{"credits":0.02,"usd":0.002,"plus_per_slice":{"credits":0.05,"usd":0.005}},"unit":"per company, plus each slice with data","note":"the employer in depth","call":{"mcp_tool":"get_company","arguments":{"id":5759},"rest":"https://alion.io/mcp/rest/get_company?id=5759"},"human":"https://alion.io/catalog?offer=company.slices&for=job%2Ff5-principal-security-engineer"},{"id":"market.stats","title":"A market slice: pay, demand and time to fill","status":"live","price":{"credits":1,"usd":0.1},"unit":"per slice","note":"pay, demand and time to fill for this role and place","call":{"mcp_tool":"market_stats"},"human":"https://alion.io/catalog?offer=market.stats&for=job%2Ff5-principal-security-engineer"},{"id":"job.search","title":"Open jobs by role, technology, place, pay and visa","status":"live","price":{"credits":0.02,"usd":0.002},"unit":"per posting in a list","note":"similar open postings","call":{"mcp_tool":"search_jobs"},"human":"https://alion.io/catalog?offer=job.search&for=job%2Ff5-principal-security-engineer"},{"id":"company.verify","title":"Is this company real and active right now","status":"pilot","price":null,"unit":"per company","request":{"url":"https://alion.io/catalog/request","method":"POST","body":"{\"offer\": \"company.verify\", \"for\": \"job/f5-principal-security-engineer\", \"note\": \"what you need it for\"}"},"human":"https://alion.io/catalog?offer=company.verify&for=job%2Ff5-principal-security-engineer"}],"agent":{"mcp":"https://alion.io/mcp/jobs","mcp_open":"https://alion.io/mcp/open","next":[{"tool":"get_job","arguments":{"id":3460939}},{"tool":"search_jobs","arguments":{"company":"f5.com","detail":"compact"}},{"tool":"match_people","arguments":{"job_id":3460939},"note":"people open to offers who fit this vacancy"}],"note":"The same data through MCP tools: https://alion.io/mcp/open needs no sign-in (compact searches, postings, people); https://alion.io/mcp with an Alion account has everything. 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