Top Penetration Testing Companies In Seattle For 2027

Seattle-area companies build and run a large share of the world’s cloud software, and many of them also make connected devices, games, aircraft parts and medical technology. That mix creates a wide attack surface: cloud accounts with thousands of permissions, APIs that change weekly, firmware that ships in physical products and, more and more, AI features that read customer data and call internal tools. Attackers are using AI to probe all of it faster, which shortens the time between a mistake going live and someone abusing it.

A penetration test shows what a skilled attacker could actually do with your weaknesses, in what order, and how to fix them. The Seattle region has an unusually deep bench of testers, partly because so many of them trained on security teams at the large software and cloud companies nearby. Local options range from research boutiques that test chips and AI models to managed IT providers that run compliance-focused network tests for small businesses.

This list covers ten penetration testing companies headquartered in the Seattle area or with a staffed Seattle-area office. For a national view, see our list of top penetration testing companies, and if you are budgeting, our guide to penetration testing cost explains what drives price.

Penetration Testing Companies In Seattle At A Glance

Company	Headquarters	Best For	Core Services
Rhino Security Labs	Seattle, WA, USA	Cloud-heavy companies on AWS, Azure or Google Cloud	Cloud penetration testing, web and mobile app testing, network testing, red team, social engineering
IOActive	Seattle, WA, USA	Device makers and critical infrastructure operators	Full stack assessments, hardware and silicon security, red and purple teaming, AI and ML security
Casaba Security	Redmond, WA, USA	Software and AI companies shipping LLM features and agents	AI and LLM security testing, cloud and application security, device security, red teaming
Leviathan Security Group	Tukwila, WA, USA	Product teams and app developers needing certification-style assessments	Web app testing, secure code review, network testing, IoT and device assessments, vCISO
Anvil Secure	Seattle, WA, USA	Hardware, embedded and platform teams that need low-level testing	White, grey and black box pentesting, code auditing, fuzzing, reverse engineering, hardware security
Mirai Security	Seattle, WA, USA	Mid-market companies that want testing alongside broader security help	Security testing and red team, Azure and Microsoft 365 assessments, application security, GRC, incident response
Kalles Group	Seattle, WA, USA	Seattle organizations that want testing tied to Microsoft 365 and zero trust work	Penetration testing, cloud security, zero trust programs, M365 security, risk assessments
Coalfire	Chicago, IL, USA (Bellevue office)	Companies pursuing FedRAMP, PCI or CMMC that need testing for an audit	Offensive testing, FedRAMP and CMMC advisory, PCI and compliance assessments, managed security
Kroll	New York, NY, USA (Seattle office)	Regulated firms that want testing linked to incident response	Network, web app, API, mobile and cloud pentests, red teaming, IoT testing, incident response
Convergence Networks	Seattle, WA, USA	Small and midsize businesses that want testing from their IT provider	External, internal, wireless, social engineering, physical and web application testing, managed IT, MDR

Best Penetration Testing Companies In Seattle For 2027

1. Rhino Security Labs — Deep-Dive Cloud Pentesting From The Makers Of Pacu

Rhino Security Labs is a Seattle penetration testing firm based at 464 12th Avenue. It runs manual, deep-dive engagements across web applications, networks and mobile apps, along with secure code review, red team assessments and social engineering tests such as spear phishing and voice calls. Its strongest area is cloud penetration testing, with dedicated services for AWS, Google Cloud and Azure environments.

Rhino created and maintains Pacu, an open-source AWS exploitation framework that penetration testers use to find and exploit configuration flaws in AWS accounts, and its research team publishes technical work on cloud attack techniques. That background gives buyers confidence that its testers understand how identity and permission mistakes chain together in the cloud, which is where many serious breaches start. Rhino is a strong fit for SaaS and technology companies that run most of their infrastructure in the cloud. For more cloud-focused options, see our list of cloud penetration testing companies.

2. IOActive — Hardware, Silicon And Full Stack Security Testing

IOActive is headquartered at 1426 Elliott Avenue West in Seattle, with offices and labs in London, Cheltenham, Madrid and Dubai. It runs full stack security assessments covering mobile, infrastructure, wireless, cloud, embedded and web systems, plus code review, reverse engineering, red and purple team exercises and AI and ML security services. It also tests chips through its silicon security practice and supports secure development programs.

IOActive is known for public research on hard targets, including attack paths to the Boeing 787 avionics network, the Sinkclose flaw in AMD processors and secrets extracted from the Raspberry Pi RP2350 chip. Its client industries include energy, aerospace and transportation, healthcare, financial services and telecom. That depth makes it the natural choice for companies that build hardware, vehicles or industrial systems and need more than a standard network test. Buyers who only need a quick web application test will find it more specialized than necessary.

3. Casaba Security — AI And LLM Red Teaming Plus Cloud And App Testing

Casaba Security is based at 16625 Redmond Way in Redmond and has operated since 2002. Its testing practice covers cloud and application security across apps, APIs, source code and AWS, Azure and Google Cloud environments, along with device security for firmware, wireless stacks and connected product backends, and red teaming. The team includes people who helped develop the Security Development Lifecycle, and its listed clients include Microsoft, Amazon, Meta and Adobe.

Casaba stands out for AI security testing. It tests LLM applications and agents, including what those systems can access, for prompt injection, data exfiltration, tool misuse and safety harms, and says it has red teamed Microsoft Copilot since 2024. It also runs Casaba Cyber Evals, which measures what AI models can do in offensive security work, and Nemesis, its AI-native offensive security platform. Casaba is a strong fit for software companies building AI products that need testers who understand both classic application flaws and model behavior.

4. Leviathan Security Group — App, Device And Cloud Application Security Assessments

Leviathan Security Group is based at 631 Strander Boulevard in Tukwila, just south of Seattle. Its testing work covers web application penetration testing, secure code review, network penetration testing and smart device and IoT assessments for products such as wearables, appliances and premarket medical technology. It also runs vendor security management, which assesses and validates the controls of third-party suppliers.

Leviathan performs several program-specific assessments that app and device makers need to reach marketplaces, including Cloud Application Security Assessment (CASA) work, App Defense Alliance mobile assessments, Nest Device Access reviews and the Shopify Certified Technology Partner program. Beyond testing, it offers virtual CISO services, tabletop exercises, audit preparation and policy gap analysis. That combination suits startups and product companies that need a test to pass a platform review and someone to help build the security program behind it. Larger enterprises can also use its vendor security service to test critical suppliers.

5. Anvil Secure — Low-Level Pentesting, Fuzzing And Hardware Reverse Engineering

Anvil Secure lists its office at 2125 Western Avenue in Seattle. Its penetration testing work spans white, grey and black box engagements, code auditing, fuzzing, reverse engineering and protocol analysis, and its core service lines cover penetration testing, application and cloud security, and embedded security. On the hardware side, it reverse engineers semiconductors and extracts firmware over JTAG to find flaws that never show up in a network scan.

Anvil also lists specialized services that point to its depth in platform security: AI security testing, OCP SAFE testing for data center hardware, post-quantum cryptography reviews, Microsoft UEFI reviews and Oracle third-party penetration tests. It supports security development lifecycle programs and training as well. Anvil is a good fit for device makers, firmware teams and infrastructure vendors that need testers comfortable working below the operating system. Buyers who mainly need a compliance-driven network test may prefer a firm built around that work.

6. Mirai Security — Red Team Testing Plus Azure And Microsoft 365 Assessments

Mirai Security has offices at 600 Stewart Street in Seattle and in Vancouver, Canada. Its security testing practice uses expert testers and a red team to provide evidence of vulnerabilities in applications and infrastructure. In one published case study, Mirai found an Active Directory weakness at PayByPhone that six years of earlier penetration testing had missed, which shows the value of a fresh, skilled set of eyes.

Mirai pairs testing with an Azure cloud security assessment, a Microsoft 365 security assessment, application security, governance, risk and compliance work aligned with SOC 2 and ISO 27001, incident response and security awareness training. Its team lists credentials including OSWE, GIAC GCSA, AWS and Azure certifications. Mirai suits mid-market organizations in healthcare, logistics, retail, finance and technology that want a single partner for testing and the follow-up work, particularly those running on Microsoft. Its incident response line also gives clients a route to help if a test reveals signs of a real compromise.

7. Kalles Group — Penetration Testing Within Zero Trust And M365 Security Programs

Kalles Group is a Seattle consulting firm that offers penetration testing as part of a wider set of security solutions, alongside cloud security, zero trust programs, Microsoft 365 security, security and risk assessments, business continuity and incident response. Its cloud security team works alongside client staff to implement and harden cloud environments, and it offers a structured Microsoft 365 security engagement.

Kalles also runs digital services such as cloud infrastructure, business intelligence and SharePoint work, which means its testers can hand findings to colleagues who help fix them. That makes it a practical choice for organizations that want a local partner to run a penetration test and then help close the gaps, especially in Microsoft-heavy environments. Buyers who need specialist testing of hardware, AI models or complex cloud permission chains should look at the boutiques higher on this list, but for local, hands-on remediation support Kalles is a sensible option.

8. Coalfire — Compliance-Grade Pentesting For FedRAMP, PCI And CMMC

Coalfire has a Washington office in the Plaza Center Building at 10900 NE 8th Street in Bellevue. Its security division, DivisionHex, runs offensive testing, defensive work and managed services, while its advisory and assessment practices cover FedRAMP, CMMC, PCI and audits across more than 85 frameworks, including CSA STAR, ISO 42001 and HITRUST. Its federal arm acts as a CMMC C3PAO.

That combination makes Coalfire a common choice for cloud software companies selling to government or handling payment data, where penetration tests must meet specific audit rules. It also works on generative and agentic AI security guidance and AI deepfake testing. Coalfire suits mid-size and large SaaS providers that need testing and certification support from one firm. Companies that only want a fast, standalone web test may find a smaller boutique quicker to engage, but for audit-bound testing its experience with assessors saves time.

9. Kroll — Penetration Testing Backed By Incident Response Experience

Kroll is a New York-headquartered risk advisory firm with a Seattle office at One Union Square, 600 University Street. Its cyber practice runs external and internal network tests, web application, API and mobile app tests, cloud penetration testing, container security reviews and IoT and hardware device testing, along with application threat modeling and an agile testing program built into the development lifecycle.

Kroll’s testers work alongside a large incident response and forensics team, so its red team engagements and test plans reflect what real attackers have done in recent breaches, including ransomware and social engineering. The firm also offers cyber risk retainers that combine proactive services with breach response. Kroll fits financial services, healthcare and professional services firms that want a single provider for testing and crisis support. To see how red teams differ from standard tests, read our guide to red teaming vs penetration testing.

10. Convergence Networks — SMB Pentesting From A Ballard Managed IT Provider

Convergence Networks has a Seattle office at 1410 NW 49th Street in Ballard, with other offices in Portland, Yakima, Ottawa, Winnipeg, Detroit and Lansing. It runs six types of penetration tests: external, internal, wireless, social engineering, physical and web application testing, delivered by certified ethical hackers and scoped to compliance needs or client goals. Each engagement ends with an executive report and a technical report.

Convergence is also a managed IT and security provider, offering helpdesk, network support, backup, managed detection and response, zero trust projects and CMMC compliance services. That makes it a practical option for small and midsize companies in construction, healthcare, legal, finance and manufacturing that want testing and remediation from the same team that runs their IT. Larger organizations with complex applications or cloud estates will want a specialist boutique for deeper web application penetration testing.

How To Choose A Penetration Testing Company In Seattle

Seattle buyers can choose from research boutiques, compliance specialists and managed IT providers. These questions help match the firm to the job.

What Exactly Do We Need Tested?

Start with the systems that would hurt most if compromised. A SaaS company may need cloud and web application penetration testing, a device maker may need hardware and firmware work, and a small business may need an external and internal network test. Pick a firm whose specialty matches your highest-risk system rather than one that lists every service.

Do We Need A Red Team Or A Standard Pentest?

A standard pentest tries to find as many weaknesses as possible in a defined scope. A red team engagement pursues a goal, such as reaching customer data, and tests whether your people and tools notice. Most companies should run regular pentests first and add red team exercises once basic issues are under control.

Can They Test Our AI Features?

If your product uses large language models or agents, ask whether the firm offers AI security testing for prompt injection, data leakage, tool misuse and unsafe outputs. Ask for an anonymized example finding and the frameworks it maps results to, such as the OWASP Top 10 for LLM Applications.

Will The Report Satisfy Our Auditors And Customers?

If the test is for SOC 2, PCI, FedRAMP or a customer review, confirm the report format, retest policy and whether the firm will provide a letter you can share. Compliance-focused firms tend to handle this well, while research boutiques may need you to specify what auditors expect.

How Senior Will The Testers Be?

Ask who will actually do the work, what certifications and experience they have, and whether any part of the test is subcontracted or automated. A short scoping call with the lead tester is one of the best ways to judge quality before you sign.

Conclusion

Seattle has penetration testing talent for almost any target, from AWS permission chains and AI agents to firmware and processor flaws. Decide what you most need tested and why, shortlist two or three firms whose specialty matches, and ask each for a sample report and a scoping call. Whichever you choose, make sure the engagement includes a retest so it ends with fixed issues, not just a list of findings.