Ask how to stop ransomware before encryption and most answers describe how to detect it faster: better telemetry, behavioral rules, canary files, automated isolation. Faster detection is worth having. It is still detection, and detection has a structural gap that speed does not close.
Why detection leaves a gap
Detection is a reaction. It waits for the attack to act, matches what it sees against known signatures or behavioral patterns, then responds. Some encryption completes inside that gap. The gap is not a tuning problem. It is the model. A control that has to recognise the attack before acting always acts after the attack has started.
Modern operators make the match harder on purpose. They alter variants, sign their binaries, and execute through legitimate administrative tooling with valid credentials. To identity and endpoint controls, that activity looks legitimate, because by its own measure it is.
The one thing every attack must do
Ransomware cannot achieve impact without changing something. It has to encrypt files, modify registry keys, establish persistence, or move laterally. An attacker can vary the technique freely, but not the requirement to make a change on the host. That requirement is the enforcement point.
Prevention, not detection
Prevention stops ransomware before it executes and requires no match. Enforce a verified known-good baseline at the kernel, so every attempted change to a protected system is evaluated at Ring 0 against that baseline before it executes. Authorized changes proceed. Everything outside the baseline is blocked. Encryption requires writing to files, and if that write is not authorized, it does not happen.
The question asked is not "does this look like something bad?" but "was this authorized?" The first question requires knowing the attack in advance and carries an exposure window between when an attack becomes possible and when a rule exists to describe it. The second requires no knowledge of the attack and carries no such window. Mimic blocks unauthorized changes in under 50 milliseconds, before encryption starts, and because no files were altered, recovery does not begin from partially encrypted data.
This is additive to the stack you already run. EDR, XDR, SIEM, SOAR and backup keep doing their jobs. Enforcement runs one layer beneath them and stops the change they were not built to stop.
The full guide
The complete method, with the four steps, the AI-powered ransomware case, and the questions a security team will ask, is at How to Stop Ransomware Before Encryption. For the control itself, see What is kernel-level enforcement security.
