Cybersecurity due diligence is the assessment an acquirer runs on a target's security posture before a deal closes, because the buyer inherits the target's risk — its vulnerabilities, breach history, compliance gaps and weak controls. It typically covers a review of controls, compliance status and incident history, plus an independent penetration test to validate the posture rather than take it on trust. Findings feed directly into valuation, deal terms and post-close remediation — serious issues can reduce the price or derail the deal. If you are the target, get tested and remediate before the process, so you enter negotiations with a clean, recent report; surprises found during diligence hurt far more than issues you disclosed and fixed. If you are the acquirer, require an independent technical assessment, not just the target's own assurances.
// 01 What is security due diligence in M&A?
When one company acquires another, it does not just buy the revenue and the customers — it inherits the security posture, including every unpatched system, every past breach, and every compliance gap. Cybersecurity due diligence is the process by which the acquirer looks under that hood before committing, to understand exactly what risk it is taking on. It sits alongside financial and legal due diligence as a standard part of any serious transaction involving a technology-dependent business.
The stakes are real. A target with an undisclosed breach, a fragile application, or a serious compliance gap can saddle the acquirer with regulatory fines, remediation costs and reputational damage after close — sometimes dwarfing the value of the deal. That is why buyers increasingly insist on validating a target's security independently, rather than relying on the seller's own account of it.
// 02 What the assessment covers
Security due diligence blends a paper review with technical validation. A thorough process looks at several dimensions:
Technical posture
An independent penetration test of the target's key systems — the objective evidence of how secure it actually is, versus how secure it claims to be.
Controls & policies
Security governance, access management, monitoring, and whether documented controls are actually operating.
Compliance status
SOC 2, ISO 27001, PCI DSS or sector-specific obligations — and any gaps that would become the acquirer's problem.
Breach & incident history
Past incidents, how they were handled, and whether any create ongoing exposure or undisclosed liability.
The penetration test is often the most revealing element, because it is the one part that cannot be talked around. A target can present polished policies; a test shows whether the systems behind them actually hold up.
// 03 Why a penetration test moves the deal
A penetration test matters in an acquisition because it converts uncertainty into fact, and deals are priced on uncertainty. Independent findings do one of three things. If the target is genuinely secure, a clean test removes a risk discount and supports the valuation. If there are serious but fixable issues, they typically become remediation conditions or a price adjustment — the buyer wants the problems fixed, or the price to reflect the cost of fixing them. And if the test uncovers something severe — an active compromise, a fundamental design flaw, evidence of an undisclosed breach — it can pause or end the deal entirely. In every case, the buyer would rather know before signing than discover it after.
// 04 If you're the target: prepare before diligence
If you expect to be acquired — or simply want to be ready if an offer comes — the smartest move is to run the acquirer's diligence on yourself, first. Commission an independent penetration test, remediate the findings, and enter the process with a clean, recent report and evidence of closure. This does two things: it removes uncertainty from the buyer's risk assessment, which protects your valuation, and it prevents the far more damaging scenario of the buyer's team discovering something you did not disclose. In diligence, a problem you found and fixed is a sign of maturity; the same problem discovered by the buyer is a red flag that erodes trust and price. Organise your compliance evidence too, and be transparent about past incidents — disclosed and managed always beats hidden and found.
// 05 If you're the acquirer: what to require
As the buyer, your goal is to validate rather than trust. Require an independent technical assessment of the target's key systems — ideally a penetration test scoped to what matters, run by a firm you engage rather than one the seller chose — alongside the review of controls, compliance and incident history. Insist that findings are documented clearly enough to feed into your valuation model and deal terms, and build a post-close remediation plan for anything that cannot be resolved before signing. The cost of a thorough security assessment is trivial next to the cost of inheriting an unknown breach, and it is one of the highest-leverage checks in the whole diligence process. We can run acquisition-focused assessments on target companies — scoped, fast, and reported for a deal audience.
// 06 Frequently asked questions
What is cybersecurity due diligence in M&A?
The acquirer's assessment of a target's security posture before closing — uncovering vulnerabilities, breach history, compliance gaps and weak controls the buyer would inherit. Usually includes an independent penetration test.
Why does a pentest matter in an acquisition?
It gives the buyer independent evidence of real posture. Findings can reduce valuation, add remediation conditions, or derail the deal. For the target, a clean recent test protects valuation.
How should a target prepare?
Get tested and remediate before diligence starts, organise compliance evidence, and disclose past incidents. Surprises found by the buyer hurt far more than issues you fixed.
What should an acquirer require?
A review of controls, compliance and incident history, plus an independent penetration test of key systems, feeding into valuation, terms and a post-close remediation plan.