EDR migration playbook: switching vendors without a detection gap
Switching EDR vendors creates a detection window if you rush the handover. A practical migration sequence for SOC teams moving without losing visibility.
The moment you sign a new EDR contract, your old platform still holds months of historical telemetry. Your new one has none. If you decommission the old agent before the new one has found its footing, you create a window where your environment is partially blind - and that window often opens at the worst possible time, when your team is distracted by rollout logistics.
This post is a practical guide for SOC teams planning an EDR vendor switch. Not a product pitch - a sequence.
Why detection gaps happen during migrations
There are three distinct layers to the problem.
Coverage gap. Endpoint rollout takes time. In a 200-device environment, you might have 40 endpoints still running the old platform while 160 are on the new one. Neither platform sees the full picture during that overlap. Lateral movement that hops between the two populations will be invisible to both.
Tuning gap. Every EDR ships with noisy default rules. Your current platform has been tuned over months or years - suppressed maintenance scripts, whitelisted backup agents, adjusted thresholds for your specific stack. None of that transfers automatically. On day one of the new platform, you will be flooded with alerts that your old platform learned to ignore years ago.
Telemetry gap. Your old platform holds 90 days (or more) of process events, network connections, and alert history. The new platform starts from zero. If an incident spans the migration boundary, your new platform cannot see the early indicators that predated the switch. That limits both detection and investigation.
Most teams treat migration as a deployment problem - get the agents installed, get the old ones off. The detection gaps are a separate problem that nobody budgets time for.
A migration sequence that preserves visibility
Run both platforms in parallel for a minimum of four weeks. Yes, it costs double agent fees for a month. It is the only way to close all three gaps simultaneously.
| Week | Activity |
|---|---|
| 1-2 | Deploy new agents to non-critical endpoints. Export all rule suppressions, false-positive lists, and exclusion paths from the old platform. |
| 2-3 | Recreate tuning in the new platform. Run alerts in both in parallel and compare volumes - significant differences show where rules need adjustment before you trust the new platform alone. |
| 3-4 | Roll out to all endpoints. Monitor for missed detections by cross-referencing alert counts across the same time windows. |
| 4+ | Retire old agents only after two clean weeks where detection coverage matches the old platform on comparable activity. |
The exact overlap depends on your environment. Any endpoints under active incident investigation should stay on both platforms until those investigations close.
What to take with you
The most valuable migration assets are not features - they are decisions your team has already made about your environment.
Suppression lists. Export every rule suppression and false-positive override. These represent months of decisions about what is normal in your environment. Even if the new platform uses different syntax, the intent carries directly. A maintenance script that fires a process injection alert on the old platform will fire one on the new platform too.
Sigma rules. If you have written custom detection logic, export it as Sigma where possible. Most modern platforms import Sigma natively, and it is a format-agnostic way to carry detection intent between vendors. If your current platform does not export Sigma, reconstruct the logic manually for your highest-priority rules before you switch.
Alert history. Before you decommission the old platform, export alert history to your SIEM or a flat archive. You will not be able to query it from the new platform, but having it means you can cross-reference if something suspicious emerges months later.
Process baselines. If your current platform holds trusted binary hashes or process baseline data, export whatever you can. Even a partial baseline seeds the new platform’s behavioural model faster than starting cold.
The step most teams skip
Validation. Most migrations end when all agents are deployed and the old platform is off. The better test is to replay a known-benign technique against the new platform and confirm your critical detections still fire.
Tools like Atomic Red Team let you run a specific MITRE ATT&CK technique in a controlled way and check whether the EDR generates the expected alert. Running a handful of T1059 (Command and Scripting Interpreter), T1547 (Boot or Logon Autostart Execution), and T1055 (Process Injection) checks after migration takes an afternoon and closes a question that every other migration step leaves open: does the new platform actually detect what I need it to detect?
If you have not validated against a real technique library, you have not finished the migration. You have moved the risk from a known vendor to an unknown detection posture in a new one.
LightEDR ships with published MITRE ATT&CK coverage detail so you can benchmark before you commit to a migration. If you are evaluating a switch and want to discuss coverage or run a parallel trial, get in touch.