diff --git a/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2019-01-01-preview/SecurityInsights.json b/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2019-01-01-preview/SecurityInsights.json
index 544974958663..8e6854d39063 100644
--- a/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2019-01-01-preview/SecurityInsights.json
+++ b/specification/securityinsights/resource-manager/Microsoft.SecurityInsights/preview/2019-01-01-preview/SecurityInsights.json
@@ -2365,7 +2365,8 @@
         "LateralMovement",
         "Collection",
         "Exfiltration",
-        "CommandAndControl"
+        "CommandAndControl",
+        "Impact"
       ],
       "type": "string",
       "x-ms-enum": {