AI Pentesting · Build vs. Buy

AI Pentesting: Build the Tool or Buy the Outcome?

Security teams are increasingly asked to justify buying AI pentesting tools from vendors instead of building one in-house. Review the research, uncover the real cost of building it yourself, and watch how one team made the call.

Considerations

Before You Commit Engineering Resources

As security leaders consider building AI pentesting tools in-house, they're encountering tough questions. It's not just a matter of selecting a model to use. Teams have to be prepared after a model finds something, and determine whether that finding holds up.

A frontier model alone is not a pentesting platform.
Paul Mote, VP of Solutions Architects at Synack

Most teams can stand up a proof of concept that finds real vulnerabilities within weeks. Turning it into a program you can trust at production scale is a different order of complexity, and that's where the real cost starts to climb.

Get the answers to the questions
  1. 01Can I Just Use Claude or GPT and Point It at My Environment?
  2. 02My Engineering Team Is Strong. Can They Build This?
  3. 03Will I Maintain Control Over My Data and the Models We Use?
  4. 04Will It Be Cheaper to Build?
  5. 05Can I Build Something Lightweight for My Internal Red Team?

Decision in practice

How Dow Approaches AI Pentesting at Scale

Dow's Cybersecurity Engineering Team evaluated several AI pentesting tools and considered building the capability internally. Ultimately, they chose Synack because replicating a dedicated vendor's platform would require high token costs and engineering overhead. Watch the conversation to hear how Dow decided on Synack.

Force multiplier

Dan Lacher Cybersecurity Engineering Team Leader, Dow
Dow evaluated several AI pentesting tools before deciding to extend its team with Synack instead of building in-house. “I really see it as a force multiplier,” Lacher said. This way, his small internal team can direct a much larger pool of testing capacity without adding headcount.

The agent harness

Mark Kuhr, Ph.D. Co-Founder & CTO, Synack
“The performance isn't even close. The harness really makes a big difference,” Kuhr said, referring to the orchestration, guardrails and decision logic wrapped around a model. It's why a lab demo and a production pentest perform so differently, and why building an agent harness is a multi-year effort, not a one-time build.

Human validation

Mark Kuhr, Ph.D. Co-Founder & CTO, Synack
“You don't want to waste your time chasing AI-generated slop and false positives,” Kuhr said. Every Sara finding still passes through human validation before it reaches a customer: the same standard Dow requires from its own testing program.

Read the Executive Brief

Beyond the Model: What It Takes to Operationalize AI Pentesting at Enterprise Scale. The five decision points from the Dow conversation, distilled for security leaders.
Read the Executive Brief →

Sara, up close

Sara Is Built for Complex Environments

Real environments don't behave like a lab. Logins break in unexpected ways, workflows branch across services, and the same vulnerability class shows up differently across different assets. Sara is built to work inside that complexity, running as a coordinated system of specialized agents shaped by the way Synack's own researchers test targets.

Built From Real Pentest Data, Not Benchmarks

13 yrs of Synack Red Team methodology, distilled into a structured workflow

Agentic frameworks built on open source models are often tuned for controlled benchmark environments. Sara's approach is modeled on how Synack's top researchers work a target, instead of a known test case.

Hundreds of Specialized Agents Per Run

300–600 sub-agents deployed per Sara pentest: recon, fuzzing, exploitation and chain-finding, working a coordinated pipeline

This isn't one free-roaming model. Each agent is purpose-built for a narrow task, which is what keeps a run focused across a real, messy attack surface instead of losing coherence after a few steps.

Adversarial Triage, Then Human Review

2 layers of validation before a finding reaches you: Sara's own adversarial triage, then Synack Red Team

Sara's discovery phase is intentionally high recall. A separate system then challenges its own findings, and Synack Red Team reviews what remains for exploitability. What reaches you is a validated risk, not a hypothesis.

Read the Technical Brief

What It Takes to Build an Agent Harness. The orchestration, guardrails and decision logic behind Sara, and why it's a multi-year effort to replicate.
Read the Technical Brief →

Coverage & Timing

Continuous Testing Keeps Pace

New assets, new cloud services and new code ship to production faster than any annual or point-in-time test can follow. By the time a report lands, the environment it describes has already changed.

Continuous pentesting closes that gap by testing as assets appear instead of waiting for the next scheduled engagement, pairing always-on AI testing with periodic, deeper human-led engagements.

Read why Synack built for continuous coverage
  • New cloud assets enter the testing workflow in near real time, instead of waiting on the next scheduled engagement
  • Always-on AI testing runs between deeper, periodic human-led engagements
  • Actionable, prioritized remediation guidance that security teams can act on immediately
  • People: AI/ML engineers plus offensive security expertise, roughly $185,000 per engineer, before a single finding ships
  • Tokens & compute: agentic workloads don't consume tokens like a chatbot; some teams have seen bills spike past $87,000 in a single month
  • Infrastructure: isolated staging environments needed to test agent behavior safely before it touches production
  • Maintenance: every model upgrade is a regression event, retesting and retuning the toolkit at scale
  • Compliance: an internal build can't produce the independent, third-party attestation that FedRAMP, DORA and most auditors require

Cost

The Bill that Arrives in Year Two

Most estimates for building an AI pentesting solution in-house are built around the initial engineering sprint. The costs that decide whether the project survives tend to show up later.

The hidden bill usually arrives in year two.
Matt Cappello, Vice President of North America Sales, Synack, The Hidden Costs of Building an AI Pentesting Solution
Read the full cost breakdown

Ready to Make the Call for Your Team?

Talk to us about your own build vs. buy evaluation, or see Sara AI Pentesting in action.