How do independent VPN audits work and what do they prove (and not prove) about no-logs claims?
Executive summary
Independent VPN audits are structured, third‑party examinations that test a provider’s systems, configurations and procedures against its no‑logs claim, typically by interviewing staff, inspecting server and configuration files, and reviewing change‑control processes; they increase transparency and lower risk but are inherently limited to a defined scope and a point in time and therefore cannot prove a perpetual or absolute absence of logging [1] [2] [3]. Reports from providers such as NordVPN, Proton, ExpressVPN and IPVanish show common audit practices and the kinds of assurances such engagements can — and cannot — deliver [2] [4] [5] [6].
1. What auditors actually do: methods and evidence
Typical independent engagements consist of interviews with employees, inspection of server configurations and technical logs, review of authentication and gateway systems, and tests of deployment and change‑management procedures; big firms and specialist security consultants alike have used these techniques when verifying no‑logs claims [1] [7] [8]. Auditors may also evaluate administrative controls such as dual‑control release processes and automated configuration management to confirm that logging settings cannot be silently changed without oversight [6] [9].
2. Standards, scope and the “point‑in‑time” reality
Many audits are performed under formal assurance frameworks — for example ISAE 3000 — or as limited assurance engagements, and the provider and auditor must agree the scope up front, which determines what systems and time windows are covered; when Deloitte or PwC examined NordVPN they explicitly described a confined review window and scope of systems evaluated [2] [1]. That very definition of scope creates the core limitation: audits attest to what was observed during testing, not to future state or every possible backdoor outside the agreed perimeter [2] [3].
3. What an audit proves: practical, not metaphysical, assurances
A successful audit can prove that the provider’s published policy was followed, that configuration files and server images did not retain traffic or connection logs, and that organizational controls exist to prevent inadvertent logging — concrete, demonstrable facts that materially raise confidence in a provider’s privacy posture [7] [6] [4]. Multiple repeating audits — as many vendors now publish annually — add cumulative assurance by showing ongoing compliance rather than a one‑off snapshot [2] [5].
4. What audits do not — and cannot — prove
Audits cannot prove that logging is technically impossible, that a future reconfiguration or compromise won’t create logs, or that a provider couldn’t be legally compelled or hacked into logging systems outside the auditor’s view; auditors warn that improper server configuration or architectural flaws could still cause accidental logging, which is why repeat audits and architectural controls matter [4] [9]. They also cannot detect covert, time‑limited logging that a provider intentionally hides unless the audit scope, tooling and timing happen to reveal it [3].
5. How to read audit claims critically
Consumers should check who performed the audit, the engagement type (limited assurance vs. broader attestations), the scope and dates, whether source code or live server images were inspected, and whether the full report is published — all factors that affect how much confidence is warranted; reputable cases often publish full or summarized reports and describe the methods used [1] [10] [11]. The existence of multi‑year audits and complementary certifications such as SOC2 or repeated Big Four assurance engagements strengthens credibility but still requires readers to understand the contractual and technical limits spelled out in each report [4] [2].
6. Bottom line for risk‑minded users
Independent audits are among the best available tools to hold VPN providers accountable and to move claims beyond marketing: they test systems, verify controls and create public records that can be challenged — but they are not proof of perpetual infallibility or immunity from legal or technical compromise, and informed trust requires reading the report’s scope, methods and limitations rather than accepting headlines alone [11] [3].