diff --git a/x-pack/plugins/cases/server/services/user_profiles/index.ts b/x-pack/plugins/cases/server/services/user_profiles/index.ts
index 5bcc2db01e9a7..9843d1781a329 100644
--- a/x-pack/plugins/cases/server/services/user_profiles/index.ts
+++ b/x-pack/plugins/cases/server/services/user_profiles/index.ts
@@ -11,11 +11,8 @@ import { fold } from 'fp-ts/lib/Either';
 import { identity } from 'fp-ts/lib/function';
 
 import { KibanaRequest, Logger } from '@kbn/core/server';
-import {
-  SecurityPluginSetup,
-  SecurityPluginStart,
-  UserProfileServiceStart,
-} from '@kbn/security-plugin/server';
+import { SecurityPluginSetup, SecurityPluginStart } from '@kbn/security-plugin/server';
+import type { UserProfile } from '@kbn/security-plugin/common';
 import { SpacesPluginStart } from '@kbn/spaces-plugin/server';
 
 import { excess, SuggestUserProfilesRequestRt, throwErrors } from '../../../common/api';
@@ -41,7 +38,7 @@ export class UserProfileService {
     this.options = options;
   }
 
-  public async suggest(request: KibanaRequest): ReturnType<UserProfileServiceStart['suggest']> {
+  public async suggest(request: KibanaRequest): Promise<UserProfile[]> {
     const params = pipe(
       excess(SuggestUserProfilesRequestRt).decode(request.body),
       fold(throwErrors(Boom.badRequest), identity)
@@ -61,6 +58,13 @@ export class UserProfileService {
         securityPluginStart: this.options.securityPluginStart,
       };
 
+      /**
+       * The limit of 100 helps prevent DDoS attacks and is also enforced by the security plugin.
+       */
+      if (size !== undefined && (size > 100 || size < 0)) {
+        throw Boom.badRequest('size must be between 0 and 100');
+      }
+
       if (!UserProfileService.isSecurityEnabled(securityPluginFields)) {
         return [];
       }
@@ -81,9 +85,8 @@ export class UserProfileService {
     } catch (error) {
       throw createCaseError({
         logger: this.logger,
-        message: `Failed to retrieve suggested user profiles in service for name: ${name} owners: [${owners.join(
-          ','
-        )}]`,
+        message: `Failed to retrieve suggested user profiles in service for name: ${name} owners: [${owners}]: ${error}`,
+        error,
       });
     }
   }
@@ -104,6 +107,13 @@ export class UserProfileService {
     );
   }
 
+  /**
+   * This function constructs the privileges required for a user to be assigned to a case. We're requiring the ability
+   * to read and update a case saved object. My thought process was that a user should at a minimum be able to read it
+   * and change its status to close it. This is does not require that the user have access to comments or various other
+   * privileges around the other entities within cases. If we move to a more granular object level permissions we'll
+   * likely need to expand this to include the privileges for the other entities as well.
+   */
   private static buildRequiredPrivileges(owners: string[], security: SecurityPluginStart) {
     const privileges: string[] = [];
     for (const owner of owners) {
diff --git a/x-pack/test/cases_api_integration/security_and_spaces/tests/common/internal/suggest_user_profiles.ts b/x-pack/test/cases_api_integration/security_and_spaces/tests/common/internal/suggest_user_profiles.ts
index 6bc89ee0d37a5..57db22d3f0432 100644
--- a/x-pack/test/cases_api_integration/security_and_spaces/tests/common/internal/suggest_user_profiles.ts
+++ b/x-pack/test/cases_api_integration/security_and_spaces/tests/common/internal/suggest_user_profiles.ts
@@ -140,8 +140,33 @@ export default function ({ getService }: FtrProviderContext) {
       expect(profiles).to.be.empty();
     });
 
-    // TODO: unskip when security plugin implements fix for size issue
-    it.skip('limits the results to one, when the size is specified as one', async () => {
+    it('returns a 400 if size is greater than 100', async () => {
+      await suggestUserProfiles({
+        supertest: supertestWithoutAuth,
+        req: {
+          name: 'blah',
+          owners: ['securitySolutionFixture'],
+          size: 101,
+        },
+        auth: { user: superUser, space: 'space1' },
+        expectedHttpCode: 400,
+      });
+    });
+
+    it('returns a 400 if size is less than 0', async () => {
+      await suggestUserProfiles({
+        supertest: supertestWithoutAuth,
+        req: {
+          name: 'blah',
+          owners: ['securitySolutionFixture'],
+          size: -1,
+        },
+        auth: { user: superUser, space: 'space1' },
+        expectedHttpCode: 400,
+      });
+    });
+
+    it('limits the results to one, when the size is specified as one', async () => {
       const profiles = await suggestUserProfiles({
         supertest: supertestWithoutAuth,
         req: {