[8.x] Fix Chart Trend by Severity Bug (#212360)

# Backport

This will backport the following commits from `main` to `8.x`:
- [Fix Chart Trend by Severity
Bug](#211735)

<!--- Backport version: 9.6.6 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sorenlouv/backport)

<!--BACKPORT [{"author":{"name":"Ido
Cohen","email":"90558359+CohenIdo@users.noreply.github.com"},"sourceCommit":{"committedDate":"2025-02-25T11:24:50Z","message":"Fix
Chart Trend by Severity
Bug","sha":"7f2df7cd427506486ac8f7a34498d0448c431992","branchLabelMapping":{"^v9.1.0$":"main","^v8.19.0$":"8.x","^v(\\d+).(\\d+).\\d+$":"$1.$2"}},"sourcePullRequest":{"labels":["release_note:skip","v9.0.0","Team:Cloud
Security","backport:prev-major","v8.16.0","v8.17.0","v8.18.0","v9.1.0"],"title":"Fix
Chart Trend by Severity
Bug","number":211735,"url":"https://github.com/elastic/kibana/pull/211735","mergeCommit":{"message":"Fix
Chart Trend by Severity
Bug","sha":"7f2df7cd427506486ac8f7a34498d0448c431992"}},"sourceBranch":"main","suggestedTargetBranches":["9.0","8.16","8.17","8.18"],"targetPullRequestStates":[{"branch":"9.0","label":"v9.0.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"8.16","label":"v8.16.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"8.17","label":"v8.17.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"8.18","label":"v8.18.0","branchLabelMappingKey":"^v(\\d+).(\\d+).\\d+$","isSourceBranch":false,"state":"NOT_CREATED"},{"branch":"main","label":"v9.1.0","branchLabelMappingKey":"^v9.1.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/211735","number":211735,"mergeCommit":{"message":"Fix
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Co-authored-by: Ido Cohen <90558359+CohenIdo@users.noreply.github.com>

x-pack/solutions/security/plugins/cloud_security_posture/server/tasks/findings_stats_task.ts

@@ -339,7 +339,7 @@ const getFindingsScoresDocIndexingPromises = (
     });
   });
 
-const getVulnStatsTrendDocIndexingPromises = (
+export const getVulnStatsTrendDocIndexingPromises = (
   esClient: ElasticsearchClient,
   vulnStatsAggs?: VulnSeverityAggs
 ) => {
@@ -348,12 +348,11 @@ const getVulnStatsTrendDocIndexingPromises = (
   const scoreByCloudAccount = Object.fromEntries(
     vulnStatsAggs.vulnerabilities_stats_by_cloud_account.buckets.map((accountScore) => {
       const cloudAccountId = accountScore.key;
-
       return [
         cloudAccountId,
         {
           cloudAccountId: accountScore.key,
-          cloudAccountName: accountScore.cloud_account_name.buckets[0].key,
+          cloudAccountName: accountScore.cloud_account_name.buckets[0]?.key || '',
           critical: accountScore.critical.doc_count,
           high: accountScore.high.doc_count,
           medium: accountScore.medium.doc_count,

x-pack/solutions/security/plugins/cloud_security_posture/server/tasks/task_state.test.ts

@@ -7,6 +7,10 @@
 
 import { cloneDeep } from 'lodash';
 import { stateSchemaByVersion } from './task_state';
+import { getVulnStatsTrendDocIndexingPromises } from './findings_stats_task';
+import { elasticsearchClientMock } from '@kbn/core-elasticsearch-client-server-mocks';
+
+const esClient = elasticsearchClientMock.createClusterClient().asScoped().asInternalUser;
 
 describe('finding stats task state', () => {
   describe('v1', () => {
@@ -35,5 +39,83 @@ describe('finding stats task state', () => {
       const result = v1.up(state);
       expect(result).not.toHaveProperty('foo');
     });
+
+    it('should return undefined if vulnStatsAggs is not provided', () => {
+      const result = getVulnStatsTrendDocIndexingPromises(esClient);
+      expect(result).toBeUndefined();
+      expect(esClient.index).not.toHaveBeenCalled();
+    });
+
+    it('should correctly process vulnerability stats and call esClient.index', async () => {
+      const vulnStatsAggs = {
+        vulnerabilities_stats_by_cloud_account: {
+          buckets: [
+            {
+              key: 'account1',
+              cloud_account_name: { buckets: [{ key: 'Account One' }] },
+              critical: { doc_count: 5 },
+              high: { doc_count: 10 },
+              medium: { doc_count: 15 },
+              low: { doc_count: 20 },
+            },
+          ],
+        },
+        critical: { doc_count: 50 },
+        high: { doc_count: 100 },
+        medium: { doc_count: 150 },
+        low: { doc_count: 200 },
+      };
+
+      await getVulnStatsTrendDocIndexingPromises(esClient, vulnStatsAggs);
+
+      expect(esClient.index).toHaveBeenCalledWith({
+        index: expect.any(String),
+        document: expect.objectContaining({
+          vulnerabilities_stats_by_cloud_account: {
+            account1: expect.objectContaining({
+              cloudAccountName: 'Account One',
+              critical: 5,
+              high: 10,
+              medium: 15,
+              low: 20,
+            }),
+          },
+        }),
+      });
+    });
+
+    it('should handle missing cloud account name gracefully', async () => {
+      const vulnStatsAggs = {
+        vulnerabilities_stats_by_cloud_account: {
+          buckets: [
+            {
+              key: 'account2',
+              cloud_account_name: { buckets: [] },
+              critical: { doc_count: 3 },
+              high: { doc_count: 6 },
+              medium: { doc_count: 9 },
+              low: { doc_count: 12 },
+            },
+          ],
+        },
+        critical: { doc_count: 30 },
+        high: { doc_count: 60 },
+        medium: { doc_count: 90 },
+        low: { doc_count: 120 },
+      };
+
+      await getVulnStatsTrendDocIndexingPromises(esClient, vulnStatsAggs);
+
+      expect(esClient.index).toHaveBeenCalledWith({
+        index: expect.any(String),
+        document: expect.objectContaining({
+          vulnerabilities_stats_by_cloud_account: {
+            account2: expect.objectContaining({
+              cloudAccountName: '',
+            }),
+          },
+        }),
+      });
+    });
   });
 });