Archived listing. The details below describe a past opening.
As a Senior Offensive Security Consultant on our Cyber Defense team, you will get the opportunity to lead adversarial testing engagements for clients across a range of industries. In this role, you will simulate real-world adversaries to identify exploitable weaknesses, validate detection and response capabilities, and help clients measurably strengthen their security posture. This is a hands-on technical role with significant client interaction and ideal for someone who thrives on solving complex problems and communicating impact to both technical teams and executive stakeholders.
From day one, you’ll be empowered by the greater Cyber & Risk team to help clients make the moves that will help them achieve their vision and help you achieve more, confidently.
Your day-to-day may include:
- Penetration Testing: Plan and execute network, application, API, and cloud penetration tests, from scoping through exploitation, post-exploitation, and reporting.
- Adversary Emulations: Design and run, threat-informed attack simulations to validate the effectiveness of client security controls and detection coverage.
- Assume-Breach: Conduct assume-breach engagements, collaborating with defensive teams to test detection, response, and containment capabilities.
- AI Red Teaming: Perform adversarial testing of AI/ML systems and LLM-enabled applications, including prompt injection, model manipulation, data exfiltration, and abuse-case testing.
- Threat Emulation: Emulate the tactics, techniques, and procedures (TTPs) of relevant threat actors, mapping activity to frameworks such as MITRE ATT&CK.
- Reporting & Communication: Produce clear, high-quality deliverables that translate technical findings into prioritized, business-relevant remediation guidance; present results to technical staff, management, and executive/board audiences.
- Client Advisory: Serve as a trusted technical advisor, helping clients understand risk, prioritize remediation, and mature their security programs.
- Practice Development: Contribute to methodology development, tooling, automation, and the mentoring of junior team members.
You have the following technical skills and qualifications:
- Bachelor’s degree in Cybersecurity, Information Technology, Computer Science, or a related field is required
- 3+ years of hands-on experience in offensive security, penetration testing, or red teaming.
- Demonstrated expertise across multiple domains (network, application, cloud, and/or internal infrastructure testing).
- Strong understanding of adversary TTPs and frameworks such as MITRE ATT&CK and ATLAS and OWASP.
- Proficiency with industry-standard tooling and command-and-control frameworks.
- Scripting and automation skills (e.g., Python, PowerShell, Bash).
- Experience conducting assume-breach or adversary emulation engagements.
- Excellent written and verbal communication skills, including the ability to produce professional, client-ready reports.
- Ability to work independently, manage multiple engagements, and meet deadlines in a client-service environment.
Preferred qualifications:
- Relevant certifications such as OSCP, OSEP, OSWE, GPEN, GXPN, GWAPT or CREST.
- Prior consulting or professional-services experience.
- Cloud security testing experience across AWS, Azure, and/or GCP.
- Experience with AI/ML or LLM security testing and adversarial techniques.
- Familiarity with breach and attack simulation platforms.
- Experience testing the security of D365 and integrations a plus.
- Contributions to the security community (research, tooling, CVEs, conference talks, or publications).
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About Us
At Grant Thornton, we believe in making business more personal and building trust into every result – for our clients and you. Here, we go beyond your expectations of a career in professional services by offering a career path with more: more opportunity, more flexibility, and more support. It’s what makes us different, and we think being different makes us better.
In the U.S., Grant Thornton delivers professional services through two specialized entities: Grant Thornton LLP, a licensed, certified public accounting (CPA) firm that provides audit and assurance services ― and Grant Thornton Advisors LLC (not a licensed CPA firm), which exclusively provides non-attest offerings, including tax and advisory services.
In 2025, Grant Thornton formed a multinational, multidisciplinary platform with Grant Thornton Ireland. The platform offers a premier Trans-Atlantic advisory and tax practice, as well as independent American and Irish audit practices. With $2.7 billion in revenues and more than 50 offices spanning the U.S., Ireland and other territories, the platform delivers a singular client experience that includes enhanced solutions and capabilities, backed by powerful technologies and a roster of 12,000 quality-driven professionals enjoying exceptional career-growth opportunities and a distinctive cross-border culture.
Grant Thornton is part of the Grant Thornton International Limited network, which provides access to its member firms in more than 150 global markets.
About the Team
The team you’re about to join is ready to help you thrive. Here’s how:
- Whether it's your work location, weekly schedule, or flex time off, we empower you with the options to work the way that it best serves your clients and your life. Consistent with the firm's hybrid work model, this position will require in-person attendance at least three days per week, either at a GT office or client site.
- Here, you are supported to prioritize your overall well-being through work-life integration options that work best for you and those in your household.
- We understand that your needs, responsibilities and experiences are different - and we think that’s a good thing. That’s why we support you with personalized and comprehensive benefits that recognize and empower all the identities, roles and aspirations that make you, well, you. See how at www.gt.com/careers
- When it comes to inclusion, we are committed to doing more than checking boxes. Explore all the ways we’re taking action for diversity, equity & inclusion at www.gt.com/careers
Here’s what you can expect next:
If you apply and are selected to interview, a Grant Thornton team member will reach out to you to schedule a time to connect. We encourage you to also check out other roles that may be a good fit for you or get to know us a little bit better at www.gt.com/careers.
Benefits:
We understand that your needs, responsibilities and experiences are different, and we think that’s a good thing. That’s why we support you with personalized and comprehensive benefits that recognize and empower all the identities, roles and aspirations that make you, well, you. For an overview of our benefit offerings, please visit: https://www.grantthornton.com/careers/rewards-and-benefits
- Benefits for internship positions: Grant Thornton interns are eligible to participate in the firm’s medical, dental and vision insurance programs and the firm’s employee assistance program. Interns also receive a minimum of 72 hours of paid sick leave, and are paid for firm holidays that fall within their internship period.
- Benefits for seasonal employee positions: Grant Thornton seasonal employees are eligible to participate in the firm’s medical, dental and vision insurance programs and the firm’s employee assistance program. Seasonal employees may also be eligible to participate in the firm’s 401(k) savings plan and employee retirement plan in accordance with applicable plan terms and eligibility requirements. Seasonal employees receive a minimum of 72 hours of paid sick leave.
Grant Thornton employees may be eligible for a discretionary, annual bonus based on individual and firm performance, subject to the terms, conditions and eligibility criteria of the applicable bonus plan or program. Interns and seasonal employees are not eligible for bonus compensation.
Additional Details:
It is the policy of Grant Thornton to promote equal employment opportunities. All personnel decisions (including, but not limited to, recruiting, hiring, training, working conditions, promotion, transfer, compensation, benefits, evaluations, and termination) are made without regard to race, color, religion, national origin, sex, age, marital or civil union status, pregnancy or pregnancy-related condition, sexual orientation, gender identity or expression, citizenship status, veteran status, disability, handicap, genetic predisposition or any other characteristic protected by applicable federal, state, or local law.
Consistent with the Americans with Disabilities Act (ADA) and applicable state and local laws, it is the policy of Grant Thornton LLP to provide reasonable accommodation when requested by a qualified applicant or employee with a disability, unless such accommodation would cause an undue hardship. The policy regarding requests for reasonable accommodation applies to all aspects of employment, including the application process. To make an accommodation request, please contact HRHelp@us.gt.com.
For Los Angeles Applicants only: We will consider for employment all qualified Applicants, including those with Criminal Histories, in a manner consistent with the requirements of applicable state and local laws, including the City of Los Angeles’ Fair Chance Initiative for Hiring Ordinance.
For Massachusetts Applicants only: It is unlawful in Massachusetts to require or administer a lie detector test as condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability. Gran Thornton does not require or administer lie detector tests as a condition of employments or continued employment.