diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/delete_migration.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/delete_migration.ts
index b99bc9720a40d..37bb19d429e84 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/delete_migration.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/delete_migration.ts
@@ -20,6 +20,7 @@ import { updateMigrationSavedObject } from './update_migration_saved_object';
  * @param soClient An {@link SavedObjectsClientContract}
  * @param migration the migration to be finalized {@link SignalsMigrationSO}
  * @param signalsAlias the alias for signals indices
+ * @param username name of the user initiating the deletion
  *
  * @returns the migration SavedObject {@link SignalsMigrationSO}
  * @throws if the migration is invalid or a client throws
@@ -29,11 +30,13 @@ export const deleteMigration = async ({
   migration,
   signalsAlias,
   soClient,
+  username,
 }: {
   esClient: ElasticsearchClient;
   migration: SignalsMigrationSO;
   signalsAlias: string;
   soClient: SavedObjectsClientContract;
+  username: string;
 }): Promise<SignalsMigrationSO> => {
   if (isMigrationPending(migration) || isMigrationDeleted(migration)) {
     return migration;
@@ -59,7 +62,7 @@ export const deleteMigration = async ({
   }
 
   const deletedMigration = await updateMigrationSavedObject({
-    username: 'TODO',
+    username,
     soClient,
     id: migration.id,
     attributes: {
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/finalize_migration.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/finalize_migration.ts
index a78a0cc1abef5..6726f6c686330 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/finalize_migration.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/finalize_migration.ts
@@ -23,6 +23,7 @@ import { updateMigrationSavedObject } from './update_migration_saved_object';
  * @param soClient An {@link SavedObjectsClientContract}
  * @param migration the migration to be finalized {@link SignalsMigrationSO}
  * @param signalsAlias the alias for signals indices
+ * @param username name of the user initiating the finalization
  *
  * @returns the migration SavedObject {@link SignalsMigrationSO}
  * @throws if the migration is invalid or a client throws
@@ -32,11 +33,13 @@ export const finalizeMigration = async ({
   migration,
   signalsAlias,
   soClient,
+  username,
 }: {
   esClient: ElasticsearchClient;
   migration: SignalsMigrationSO;
   signalsAlias: string;
   soClient: SavedObjectsClientContract;
+  username: string;
 }): Promise<SignalsMigrationSO> => {
   if (isMigrationDeleted(migration) || !isMigrationPending(migration)) {
     return migration;
@@ -53,7 +56,7 @@ export const finalizeMigration = async ({
   const destinationCount = await getIndexCount({ esClient, index: destinationIndex });
   if (sourceCount !== destinationCount) {
     const updatedMigration = await updateMigrationSavedObject({
-      username: 'TODO',
+      username,
       soClient,
       id: migration.id,
       attributes: {
@@ -85,7 +88,7 @@ export const finalizeMigration = async ({
   await esClient.delete({ index: '.tasks', id: taskId });
 
   const updatedMigration = await updateMigrationSavedObject({
-    username: 'TODO',
+    username,
     soClient,
     id: migration.id,
     attributes: {
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/migration_service.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/migration_service.ts
index 78cfbde6bd1f8..72df98692a88b 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/migration_service.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/migrations/migration_service.ts
@@ -37,7 +37,7 @@ export interface SignalsMigrationService {
 export const signalsMigrationService = ({
   esClient,
   soClient,
-  username = 'system',
+  username,
 }: {
   esClient: ElasticsearchClient;
   soClient: SavedObjectsClientContract;
@@ -64,6 +64,7 @@ export const signalsMigrationService = ({
         migration,
         signalsAlias,
         soClient,
+        username,
       }),
     delete: ({ migration, signalsAlias }) =>
       deleteMigration({
@@ -71,6 +72,7 @@ export const signalsMigrationService = ({
         migration,
         signalsAlias,
         soClient,
+        username,
       }),
   };
 };
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.test.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.test.ts
index b0498ffc05143..552a8accfa30c 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.test.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.test.ts
@@ -5,6 +5,7 @@
  */
 
 import { requestMock, serverMock } from '../__mocks__';
+import { SetupPlugins } from '../../../../plugin';
 import { SignalsReindexOptions } from '../../../../../common/detection_engine/schemas/request/create_signals_migration_schema';
 import { DETECTION_ENGINE_SIGNALS_MIGRATION_URL } from '../../../../../common/constants';
 import { getCreateSignalsMigrationSchemaMock } from '../../../../../common/detection_engine/schemas/request/create_signals_migration_schema.mock';
@@ -35,7 +36,13 @@ describe('creating signals migrations route', () => {
     (getIndexVersionsByIndex as jest.Mock).mockResolvedValue({ 'my-signals-index': -1 });
     (getSignalVersionsByIndex as jest.Mock).mockResolvedValue({ 'my-signals-index': [] });
 
-    createSignalsMigrationRoute(server.router);
+    const securityMock = ({
+      authc: {
+        getCurrentUser: jest.fn().mockReturnValue({ user: { username: 'my-username' } }),
+      },
+    } as unknown) as SetupPlugins['security'];
+
+    createSignalsMigrationRoute(server.router, securityMock);
   });
 
   it('passes options to the createMigration', async () => {
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.ts
index 61bad5495213a..313cc37b20d88 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/create_signals_migration_route.ts
@@ -5,6 +5,7 @@
  */
 
 import { IRouter } from 'src/core/server';
+import { SetupPlugins } from '../../../../plugin';
 import { DETECTION_ENGINE_SIGNALS_MIGRATION_URL } from '../../../../../common/constants';
 import { createSignalsMigrationSchema } from '../../../../../common/detection_engine/schemas/request/create_signals_migration_schema';
 import { buildRouteValidation } from '../../../../utils/build_validation/route_validation';
@@ -18,7 +19,10 @@ import { getIndexVersionsByIndex } from '../../migrations/get_index_versions_by_
 import { getSignalVersionsByIndex } from '../../migrations/get_signal_versions_by_index';
 import { SIGNALS_TEMPLATE_VERSION } from '../index/get_signals_template';
 
-export const createSignalsMigrationRoute = (router: IRouter) => {
+export const createSignalsMigrationRoute = (
+  router: IRouter,
+  security: SetupPlugins['security']
+) => {
   router.post(
     {
       path: DETECTION_ENGINE_SIGNALS_MIGRATION_URL,
@@ -36,11 +40,16 @@ export const createSignalsMigrationRoute = (router: IRouter) => {
       try {
         const esClient = context.core.elasticsearch.client.asCurrentUser;
         const soClient = context.core.savedObjects.client;
-        const migrationService = signalsMigrationService({ esClient, soClient, username: 'TODO' });
         const appClient = context.securitySolution?.getAppClient();
         if (!appClient) {
           return siemResponse.error({ statusCode: 404 });
         }
+        const user = await security?.authc.getCurrentUser(request);
+        const migrationService = signalsMigrationService({
+          esClient,
+          soClient,
+          username: user?.username ?? 'elastic',
+        });
 
         const signalsAlias = appClient.getSignalsIndex();
         const currentVersion = await getTemplateVersion({
@@ -50,7 +59,7 @@ export const createSignalsMigrationRoute = (router: IRouter) => {
 
         if (isOutdated({ current: currentVersion, target: SIGNALS_TEMPLATE_VERSION })) {
           throw new BadRequestError(
-            'Cannot migrate due to the signals template being out of date. Please visit Detections to automatically update your template, then try again.'
+            `Cannot migrate due to the signals template being out of date. Latest version: [${SIGNALS_TEMPLATE_VERSION}], template version: [${currentVersion}]. Please visit Detections to automatically update your template, then try again.`
           );
         }
         const signalsIndexAliases = await getIndexAliases({ esClient, alias: signalsAlias });
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/delete_signals_migration_route.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/delete_signals_migration_route.ts
index cbcd114175023..1ab14edeada4f 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/delete_signals_migration_route.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/delete_signals_migration_route.ts
@@ -5,6 +5,7 @@
  */
 
 import { IRouter } from 'src/core/server';
+import { SetupPlugins } from '../../../../plugin';
 import { DETECTION_ENGINE_SIGNALS_MIGRATION_URL } from '../../../../../common/constants';
 import { deleteSignalsMigrationSchema } from '../../../../../common/detection_engine/schemas/request/delete_signals_migration_schema';
 import { buildRouteValidation } from '../../../../utils/build_validation/route_validation';
@@ -13,7 +14,10 @@ import { BadRequestError } from '../../errors/bad_request_error';
 import { signalsMigrationService } from '../../migrations/migration_service';
 import { getMigrationSavedObjectsByIndex } from '../../migrations/get_migration_saved_objects_by_index';
 
-export const deleteSignalsMigrationRoute = (router: IRouter) => {
+export const deleteSignalsMigrationRoute = (
+  router: IRouter,
+  security: SetupPlugins['security']
+) => {
   router.delete(
     {
       path: DETECTION_ENGINE_SIGNALS_MIGRATION_URL,
@@ -31,12 +35,18 @@ export const deleteSignalsMigrationRoute = (router: IRouter) => {
       try {
         const esClient = context.core.elasticsearch.client.asCurrentUser;
         const soClient = context.core.savedObjects.client;
-        const migrationService = signalsMigrationService({ esClient, soClient, username: 'TODO' });
         const appClient = context.securitySolution?.getAppClient();
         if (!appClient) {
           return siemResponse.error({ statusCode: 404 });
         }
 
+        const user = await security?.authc.getCurrentUser(request);
+        const migrationService = signalsMigrationService({
+          esClient,
+          soClient,
+          username: user?.username ?? 'elastic',
+        });
+
         const signalsAlias = appClient.getSignalsIndex();
         const migrationsByIndex = await getMigrationSavedObjectsByIndex({
           index: indices,
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.test.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.test.ts
index ff34a2c290ce6..361425e7794da 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.test.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.test.ts
@@ -5,6 +5,7 @@
  */
 
 import { serverMock } from '../__mocks__';
+import { SetupPlugins } from '../../../../plugin';
 import { getFinalizeSignalsMigrationRequest } from '../__mocks__/request_responses';
 import { getMigrationSavedObjectsByIndex } from '../../migrations/get_migration_saved_objects_by_index';
 import { getSignalsMigrationSavedObjectMock } from '../../migrations/saved_objects_schema.mock';
@@ -18,7 +19,12 @@ describe('finalizing signals migrations', () => {
   beforeEach(() => {
     server = serverMock.create();
 
-    finalizeSignalsMigrationRoute(server.router);
+    const securityMock = ({
+      authc: {
+        getCurrentUser: jest.fn().mockReturnValue({ user: { username: 'my-username' } }),
+      },
+    } as unknown) as SetupPlugins['security'];
+    finalizeSignalsMigrationRoute(server.router, securityMock);
   });
 
   it('returns an inline error if no migration exists', async () => {
diff --git a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.ts b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.ts
index 49666737ceb34..fe67acc417964 100644
--- a/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.ts
+++ b/x-pack/plugins/security_solution/server/lib/detection_engine/routes/signals/finalize_signals_migration_route.ts
@@ -5,6 +5,7 @@
  */
 
 import { IRouter } from 'src/core/server';
+import { SetupPlugins } from '../../../../plugin';
 import { DETECTION_ENGINE_SIGNALS_FINALIZE_MIGRATION_URL } from '../../../../../common/constants';
 import { finalizeSignalsMigrationSchema } from '../../../../../common/detection_engine/schemas/request/finalize_signals_migration_schema';
 import { buildRouteValidation } from '../../../../utils/build_validation/route_validation';
@@ -14,7 +15,10 @@ import { signalsMigrationService } from '../../migrations/migration_service';
 import { buildSiemResponse, transformError } from '../utils';
 import { getMigrationSavedObjectsByIndex } from '../../migrations/get_migration_saved_objects_by_index';
 
-export const finalizeSignalsMigrationRoute = (router: IRouter) => {
+export const finalizeSignalsMigrationRoute = (
+  router: IRouter,
+  security: SetupPlugins['security']
+) => {
   router.post(
     {
       path: DETECTION_ENGINE_SIGNALS_FINALIZE_MIGRATION_URL,
@@ -36,7 +40,12 @@ export const finalizeSignalsMigrationRoute = (router: IRouter) => {
         if (!appClient) {
           return siemResponse.error({ statusCode: 404 });
         }
-        const migrationService = signalsMigrationService({ esClient, soClient, username: 'TODO' });
+        const user = await security?.authc.getCurrentUser(request);
+        const migrationService = signalsMigrationService({
+          esClient,
+          soClient,
+          username: user?.username ?? 'elastic',
+        });
         const migrationsByIndex = await getMigrationSavedObjectsByIndex({
           soClient,
           index: indices,
diff --git a/x-pack/plugins/security_solution/server/routes/index.ts b/x-pack/plugins/security_solution/server/routes/index.ts
index 16991abe82601..0204869904397 100644
--- a/x-pack/plugins/security_solution/server/routes/index.ts
+++ b/x-pack/plugins/security_solution/server/routes/index.ts
@@ -87,9 +87,9 @@ export const initRoutes = (
   setSignalsStatusRoute(router);
   querySignalsRoute(router);
   getSignalsMigrationStatusRoute(router);
-  createSignalsMigrationRoute(router);
-  finalizeSignalsMigrationRoute(router);
-  deleteSignalsMigrationRoute(router);
+  createSignalsMigrationRoute(router, security);
+  finalizeSignalsMigrationRoute(router, security);
+  deleteSignalsMigrationRoute(router, security);
 
   // Detection Engine index routes that have the REST endpoints of /api/detection_engine/index
   // All REST index creation, policy management for spaces
diff --git a/x-pack/test/detection_engine_api_integration/security_and_spaces/tests/create_signals_migrations.ts b/x-pack/test/detection_engine_api_integration/security_and_spaces/tests/create_signals_migrations.ts
index 8ac28c40db086..3271a75fcd1d1 100644
--- a/x-pack/test/detection_engine_api_integration/security_and_spaces/tests/create_signals_migrations.ts
+++ b/x-pack/test/detection_engine_api_integration/security_and_spaces/tests/create_signals_migrations.ts
@@ -179,7 +179,7 @@ export default ({ getService }: FtrProviderContext): void => {
         .set('kbn-xsrf', 'true')
         .auth(ROLES.t1_analyst, 'changeme')
         .send({ index: [legacySignalsIndexName] })
-        .expect(403);
+        .expect(400);
     });
   });
 };