Security-Hardening Runde 10: Security-Monitoring + Alerting

Defense-in-Depth für alles, was in den ersten 9 Runden nicht durch Code
verhindert wurde: zumindest gesehen + alarmiert werden.

📊 SecurityEvent-Tabelle (Prisma)
- Type/Severity/IP/User/Endpoint + Indexen für Filter+Threshold-Detection
- Trennt sich vom AuditLog: AuditLog ist forensisch + hash-gekettet,
  SecurityEvent ist optimiert für Realtime-Alerting + Aggregation.

🪝 Hooks an kritischen Stellen
- Login (Success/Failed) – auth.controller
- Logout, Password-Reset (Request + Confirm) – auth.controller
- Rate-Limit-Hit – middleware/rateLimit
- IDOR-403 – utils/accessControl (canAccessCustomer / canAccessContract)
- SSRF-Block – emailProvider.controller (test-connection + test-mail-access)
- JWT-Reject (alg=none, expired, manipuliert) – middleware/auth

🚨 Threshold-Detection + Alerting (securityAlert.service.ts)
- Cron jede Minute: prüft Brute-Force-Patterns je IP
  - 10× LOGIN_FAILED in 60 min  → CRITICAL Brute-Force-Verdacht
  -  5× ACCESS_DENIED in 5 min  → CRITICAL IDOR-Probing-Verdacht
  -  3× SSRF_BLOCKED in 60 min  → CRITICAL SSRF-Probing
  -  3× TOKEN_REJECTED HIGH in 5 min → CRITICAL JWT-Manipulation
- CRITICAL-Events: Sofort-Alert per E-Mail (debounced)
- Cron stündlich: Digest mit HIGH+MEDIUM-Events (wenn aktiviert)
- Sofort-Alert + Digest laufen über System-E-Mail-Provider
  (gleicher Pfad wie Geburtstagsgrüße, Passwort-Reset)

🖥 Frontend: Settings → "Sicherheits-Monitoring"
- Alert-E-Mail-Adresse + Digest-Toggle
- Test-Alert-Button + Digest-jetzt-Button
- Stats-Cards pro Severity (CRITICAL/HIGH/MEDIUM/LOW/INFO)
- Filter (Type/Severity/Search/IP) + Pagination
- Auto-Refresh alle 30 s
- Verlinkt aus Settings-Übersicht (settings:read Permission)

🧪 Live-verifiziert
- Login-Fehlversuch → LOGIN_FAILED Event
- Portal probt 4× fremde Customer-IDs → 4× ACCESS_DENIED
- SSRF-Probe (169.254.169.254) → SSRF_BLOCKED Event
- 12× LOGIN_FAILED simuliert → Cron erzeugt CRITICAL nach ≤60s
- CRITICAL-Sofort-Alert binnen 30s zugestellt
- Test-Alert-Button: E-Mail zugestellt
- Hourly-Digest mit 5 Events: E-Mail mit Tabelle zugestellt

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/src/controllers/emailProvider.controller.ts

@@ -8,6 +8,7 @@ import { testImapConnection, ImapCredentials } from '../services/imapService.js'
 import { testSmtpConnection, SmtpCredentials } from '../services/smtpService.js';
 import { decrypt } from '../utils/encryption.js';
 import { assertAllowedHost, safeResolveHost } from '../utils/ssrfGuard.js';
+import { emit as emitSecurityEvent, contextFromRequest } from '../services/securityMonitor.service.js';
 import { PrismaClient } from '@prisma/client';
 
 const prisma = new PrismaClient();
@@ -128,6 +129,17 @@ export async function testConnection(req: Request, res: Response): Promise<void>
         await safeResolveHost(url.hostname, 'apiUrl-Host');
       } catch (err) {
         if (err instanceof Error && (err.message.includes('geblockte') || err.message.includes('DNS'))) {
+          const ctx = contextFromRequest(req);
+          emitSecurityEvent({
+            type: 'SSRF_BLOCKED',
+            severity: 'HIGH',
+            message: err.message,
+            ipAddress: ctx.ipAddress,
+            userId: ctx.userId,
+            userEmail: ctx.userEmail,
+            endpoint: ctx.endpoint,
+            details: { apiUrl: testData.apiUrl },
+          });
           res.status(400).json({ success: false, error: err.message } as ApiResponse);
           return;
         }
@@ -243,6 +255,17 @@ export async function testMailAccess(req: Request, res: Response): Promise<void>
         safeResolveHost(imapServer, 'IMAP-Server'),
       ]);
     } catch (err) {
+      const ctx = contextFromRequest(req);
+      emitSecurityEvent({
+        type: 'SSRF_BLOCKED',
+        severity: 'HIGH',
+        message: err instanceof Error ? err.message : 'Ungültige Server-Adresse',
+        ipAddress: ctx.ipAddress,
+        userId: ctx.userId,
+        userEmail: ctx.userEmail,
+        endpoint: ctx.endpoint,
+        details: { smtpServer, imapServer },
+      });
       res.status(400).json({
         success: false,
         error: err instanceof Error ? err.message : 'Ungültige Server-Adresse',