feat: Security Audit Auto-Fix Buttons + manuelle Dokumentation (docs/security-audit.md)

docs/security-audit.md

@@ -0,0 +1,270 @@
+# Security Audit — archivmail
+
+Dieses Dokument beschreibt alle Security-Checks die das System automatisch durchführt,
+welche Werte als sicher gelten und wie Probleme manuell behoben werden können.
+
+---
+
+## Übersicht der Checks
+
+| Check                  | OK-Kriterium                                 | Auto-Fix verfügbar |
+|------------------------|----------------------------------------------|--------------------|
+| Firewall (nftables)    | Input-Chain policy: drop                     | Ja                 |
+| Port 3000 (Next.js)    | Nicht in Whitelist                           | Nein (via Firewall)|
+| Port 8080 (Go Backend) | Nicht in Whitelist                           | Nein (via Firewall)|
+| HTTPS (TLS)            | Port 443 in Firewall + Zertifikat vorhanden  | Nein (manuell)     |
+| SSH Root-Login         | `prohibit-password` oder `no`                | Ja                 |
+| SSH Passwort-Auth      | `PasswordAuthentication no`                  | Ja                 |
+| Fail2ban               | Dienst aktiv                                 | Ja                 |
+
+---
+
+## 1. Firewall (nftables)
+
+### Was wird geprüft
+Ob `nft list ruleset` eine Input-Chain mit `policy drop` zurückgibt.
+Whitelist-Modus: Nur explizit erlaubte Ports sind erreichbar.
+
+### Erlaubte externe Ports
+| Port | Dienst            |
+|------|-------------------|
+| 22   | SSH               |
+| 80   | nginx (Web-UI)    |
+| 2525 | SMTP Einlieferung |
+
+### Manuell prüfen
+```bash
+ssh root@192.168.1.131
+
+# Aktuelle Regeln anzeigen
+nft list ruleset
+
+# Offene Ports prüfen
+ss -tlnp
+```
+
+### Manuell beheben
+```bash
+# Konfiguration neu laden
+nft -f /etc/nftables.conf
+
+# Beim Systemstart aktivieren
+systemctl enable nftables
+systemctl restart nftables
+
+# Prüfen ob Regeln aktiv sind
+nft list ruleset | grep "policy drop"
+```
+
+### Konfigurationsdatei
+`/etc/nftables.conf` — Änderungen hier sind persistent.
+
+---
+
+## 2. Port 3000 / Port 8080
+
+### Was wird geprüft
+Ob diese Ports explizit in der Firewall-Whitelist stehen.
+Beide Dienste sollen nur intern erreichbar sein (nginx proxied den Zugriff).
+
+### Warum gefährlich
+- **Port 3000**: Next.js Frontend — keine eigene Authentifizierung auf diesem Port
+- **Port 8080**: Go Backend REST API — direkte API-Zugriffe ohne nginx möglich
+
+### Manuell prüfen
+```bash
+# Lauscht Port 3000 auf allen Interfaces?
+ss -tlnp | grep 3000
+# => Wenn "0.0.0.0:3000" erscheint, ist er intern offen (Firewall muss blockieren)
+
+# Ist Port von außen erreichbar?
+nft list ruleset | grep "dport 3000"
+# => Wenn keine Zeile erscheint: gut (policy drop blockiert ihn)
+```
+
+### Manuell beheben (falls Firewall fehlt)
+```bash
+# Firewall neu laden — blockiert automatisch 3000 und 8080
+nft -f /etc/nftables.conf
+```
+
+---
+
+## 3. HTTPS (TLS)
+
+### Was wird geprüft
+Ob Port 443 in der Firewall freigegeben ist.
+Aktuell läuft archivmail nur über HTTP (Port 80) — Verbindungen sind unverschlüsselt.
+
+### Warum wichtig
+Ohne TLS werden Passwörter und E-Mail-Inhalte im Klartext übertragen.
+
+### Manuell einrichten (Let's Encrypt / certbot)
+```bash
+ssh root@192.168.1.131
+
+# certbot installieren
+apt-get install -y certbot python3-certbot-nginx
+
+# Zertifikat ausstellen (Domain muss auf den Server zeigen)
+certbot --nginx -d archivmail.example.com
+
+# Firewall: Port 443 freigeben
+# In /etc/nftables.conf folgende Zeile in chain input ergänzen:
+#   tcp dport 443 accept
+nft -f /etc/nftables.conf
+
+# Automatische Erneuerung prüfen
+certbot renew --dry-run
+```
+
+### nginx nach certbot
+certbot passt die nginx-Konfiguration automatisch an und fügt SSL + Redirect HTTP→HTTPS hinzu.
+
+---
+
+## 4. SSH Root-Login
+
+### Was wird geprüft
+Den Wert von `PermitRootLogin` in `/etc/ssh/sshd_config`.
+
+| Wert               | Bewertung |
+|--------------------|-----------|
+| `no`               | OK        |
+| `prohibit-password`| OK (Key-Auth für root erlaubt) |
+| `yes`              | Warnung   |
+| nicht gesetzt      | Warnung (Default ist prohibit-password) |
+
+### Manuell prüfen
+```bash
+grep -i "PermitRootLogin" /etc/ssh/sshd_config
+```
+
+### Manuell beheben
+```bash
+# Datei bearbeiten
+nano /etc/ssh/sshd_config
+
+# Zeile setzen oder ändern:
+PermitRootLogin prohibit-password
+
+# SSH-Dienst neu starten
+systemctl restart ssh
+
+# Prüfen
+sshd -T | grep permitrootlogin
+```
+
+---
+
+## 5. SSH Passwort-Authentifizierung
+
+### Was wird geprüft
+Den Wert von `PasswordAuthentication` in `/etc/ssh/sshd_config`.
+Empfehlung: Nur SSH-Key-Authentifizierung erlauben.
+
+### Manuell prüfen
+```bash
+grep -i "PasswordAuthentication" /etc/ssh/sshd_config
+sshd -T | grep passwordauthentication
+```
+
+### Manuell beheben
+```bash
+# Sicherstellen dass ein SSH-Key hinterlegt ist, BEVOR Passwort-Auth deaktiviert wird
+cat ~/.ssh/authorized_keys   # muss mindestens einen Eintrag enthalten
+
+# Dann in /etc/ssh/sshd_config:
+PasswordAuthentication no
+
+# SSH neu starten
+systemctl restart ssh
+```
+
+> **Warnung:** Passwort-Auth nur deaktivieren wenn ein SSH-Key in `~/.ssh/authorized_keys` vorhanden ist.
+> Sonst ist kein Login mehr möglich.
+
+---
+
+## 6. Fail2ban
+
+### Was wird geprüft
+Ob der `fail2ban`-Systemd-Dienst aktiv ist.
+
+### Was ist Fail2ban
+Fail2ban überwacht Log-Dateien und blockiert IPs automatisch bei zu vielen fehlgeschlagenen Login-Versuchen (Brute-Force-Schutz).
+
+### Manuell prüfen
+```bash
+systemctl status fail2ban
+
+# Aktive Jails anzeigen
+fail2ban-client status
+
+# SSH-Jail prüfen
+fail2ban-client status sshd
+
+# Gesperrte IPs anzeigen
+fail2ban-client status sshd | grep "Banned IP"
+```
+
+### Manuell installieren und konfigurieren
+```bash
+apt-get install -y fail2ban
+
+# Konfiguration erstellen
+cat > /etc/fail2ban/jail.local << 'EOF'
+[sshd]
+enabled = true
+maxretry = 5
+bantime = 3600
+findtime = 600
+
+[nginx-http-auth]
+enabled = true
+EOF
+
+systemctl enable fail2ban
+systemctl start fail2ban
+
+# Prüfen
+fail2ban-client status
+```
+
+### Gesperrte IP manuell entsperren
+```bash
+fail2ban-client set sshd unbanip <IP-Adresse>
+```
+
+---
+
+## Kompletter manueller Audit (alle Checks auf einmal)
+
+```bash
+ssh root@192.168.1.131
+
+echo "=== Firewall ==="
+nft list ruleset | grep -E "policy|dport"
+
+echo "=== Offene Ports ==="
+ss -tlnp
+
+echo "=== SSH Config ==="
+sshd -T | grep -E "permitrootlogin|passwordauthentication"
+
+echo "=== Fail2ban ==="
+systemctl is-active fail2ban
+fail2ban-client status 2>/dev/null || echo "nicht installiert"
+
+echo "=== nftables Dienst ==="
+systemctl is-enabled nftables
+```
+
+---
+
+## Weiterführende Ressourcen
+
+- [Debian SSH Hardening](https://wiki.debian.org/SSH)
+- [nftables Dokumentation](https://wiki.nftables.org/)
+- [Fail2ban Dokumentation](https://www.fail2ban.org/wiki/index.php/MANUAL_0_8)
+- [Let's Encrypt / certbot](https://certbot.eff.org/)

internal/api/server.go

@@ -106,6 +106,7 @@ func (s *Server) routes() {
 
 	s.mux.HandleFunc("GET /api/admin/system/stats", s.authMiddleware(s.requireRole(userstore.RoleAdmin, s.handleSystemStats)))
 	s.mux.HandleFunc("GET /api/admin/security/audit", s.authMiddleware(s.requireRole(userstore.RoleAdmin, s.handleSecurityAudit)))
+	s.mux.HandleFunc("POST /api/admin/security/fix", s.authMiddleware(s.requireRole(userstore.RoleAdmin, s.handleSecurityFix)))
 
 	// Export routes
 	s.mux.HandleFunc("GET /api/export/pdf/{id}", s.authMiddleware(s.requireMailAccess(s.handleExportPDF)))
@@ -1598,3 +1599,123 @@ func (s *Server) handleSecurityAudit(w http.ResponseWriter, r *http.Request) {
 		"run_at": time.Now().UTC().Format(time.RFC3339),
 	})
 }
+
+// ── Security Fix ────────────────────────────────────────────────────────────
+
+// allowedFixActions is a strict whitelist — only these actions may be executed.
+var allowedFixActions = map[string]bool{
+	"install_fail2ban":      true,
+	"enable_firewall":       true,
+	"fix_ssh_password_auth": true,
+	"fix_ssh_root_login":    true,
+}
+
+func (s *Server) handleSecurityFix(w http.ResponseWriter, r *http.Request) {
+	var body struct {
+		Action string `json:"action"`
+	}
+	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	if !allowedFixActions[body.Action] {
+		writeError(w, http.StatusBadRequest, "unknown action: "+body.Action)
+		return
+	}
+
+	ctx := r.Context()
+	var msg string
+	var fixErr error
+
+	switch body.Action {
+
+	case "install_fail2ban":
+		// Install fail2ban if not present
+		if _, err := exec.LookPath("fail2ban-client"); err != nil {
+			out, err := exec.CommandContext(ctx, "apt-get", "install", "-y", "fail2ban").CombinedOutput()
+			if err != nil {
+				writeError(w, http.StatusInternalServerError, "apt-get install fail2ban: "+string(out))
+				return
+			}
+		}
+		// Write a minimal jail.local if not already present
+		jailPath := "/etc/fail2ban/jail.local"
+		if _, err := os.Stat(jailPath); os.IsNotExist(err) {
+			jailConf := "[sshd]\nenabled = true\nmaxretry = 5\nbantime = 3600\nfindtime = 600\n"
+			if err := os.WriteFile(jailPath, []byte(jailConf), 0644); err != nil {
+				writeError(w, http.StatusInternalServerError, "could not write jail.local: "+err.Error())
+				return
+			}
+		}
+		// Enable and start
+		exec.CommandContext(ctx, "systemctl", "enable", "fail2ban").Run()
+		out, err := exec.CommandContext(ctx, "systemctl", "restart", "fail2ban").CombinedOutput()
+		if err != nil {
+			fixErr = fmt.Errorf("systemctl restart fail2ban: %s", string(out))
+		} else {
+			msg = "Fail2ban installiert, SSH-Jail aktiviert und Dienst gestartet."
+		}
+
+	case "enable_firewall":
+		// Reload rules from /etc/nftables.conf and enable service
+		out, err := exec.CommandContext(ctx, "nft", "-f", "/etc/nftables.conf").CombinedOutput()
+		if err != nil {
+			writeError(w, http.StatusInternalServerError, "nft -f /etc/nftables.conf: "+string(out))
+			return
+		}
+		exec.CommandContext(ctx, "systemctl", "enable", "nftables").Run()
+		msg = "nftables-Regeln neu geladen und Dienst aktiviert."
+
+	case "fix_ssh_password_auth":
+		fixErr = sshConfigSet("PasswordAuthentication", "no")
+		if fixErr == nil {
+			out, err := exec.CommandContext(ctx, "systemctl", "restart", "ssh").CombinedOutput()
+			if err != nil {
+				fixErr = fmt.Errorf("systemctl restart ssh: %s", string(out))
+			} else {
+				msg = "PasswordAuthentication auf 'no' gesetzt, SSH neu gestartet."
+			}
+		}
+
+	case "fix_ssh_root_login":
+		fixErr = sshConfigSet("PermitRootLogin", "prohibit-password")
+		if fixErr == nil {
+			out, err := exec.CommandContext(ctx, "systemctl", "restart", "ssh").CombinedOutput()
+			if err != nil {
+				fixErr = fmt.Errorf("systemctl restart ssh: %s", string(out))
+			} else {
+				msg = "PermitRootLogin auf 'prohibit-password' gesetzt, SSH neu gestartet."
+			}
+		}
+	}
+
+	if fixErr != nil {
+		writeError(w, http.StatusInternalServerError, fixErr.Error())
+		return
+	}
+	writeJSON(w, http.StatusOK, map[string]string{"message": msg})
+}
+
+// sshConfigSet sets or replaces a directive in /etc/ssh/sshd_config.
+// Commented-out lines are left untouched; the active directive is updated or appended.
+func sshConfigSet(key, value string) error {
+	const path = "/etc/ssh/sshd_config"
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return fmt.Errorf("read sshd_config: %w", err)
+	}
+	lines := strings.Split(string(data), "\n")
+	keyLower := strings.ToLower(key)
+	found := false
+	for i, l := range lines {
+		tl := strings.ToLower(strings.TrimSpace(l))
+		if strings.HasPrefix(tl, keyLower) && !strings.HasPrefix(strings.TrimSpace(l), "#") {
+			lines[i] = key + " " + value
+			found = true
+		}
+	}
+	if !found {
+		lines = append(lines, key+" "+value)
+	}
+	return os.WriteFile(path, []byte(strings.Join(lines, "\n")), 0644)
+}

src/app/admin/page.tsx

@@ -18,6 +18,7 @@ import {
   uploadMailFiles,
   getUploadProgress,
   getSecurityAudit,
+  fixSecurityIssue,
   type User,
   type AuditEntry,
   type SMTPStatus,
@@ -126,6 +127,8 @@ export default function AdminPage() {
   const [securityAudit, setSecurityAudit] = useState<SecurityAuditResult | null>(null);
   const [securityLoading, setSecurityLoading] = useState(false);
   const [securityError, setSecurityError] = useState("");
+  const [fixLoading, setFixLoading] = useState<string | null>(null);
+  const [fixMessage, setFixMessage] = useState("");
 
   // Upload state
   const [uploadDragging, setUploadDragging] = useState(false);
@@ -352,6 +355,7 @@ export default function AdminPage() {
   async function runSecurityAudit() {
     setSecurityLoading(true);
     setSecurityError("");
+    setFixMessage("");
     try {
       const result = await getSecurityAudit();
       setSecurityAudit(result);
@@ -362,6 +366,22 @@ export default function AdminPage() {
     }
   }
 
+  async function runFix(action: string) {
+    setFixLoading(action);
+    setFixMessage("");
+    setSecurityError("");
+    try {
+      const res = await fixSecurityIssue(action);
+      setFixMessage(res.message);
+      // Re-run audit automatically to reflect new state
+      await runSecurityAudit();
+    } catch (e: unknown) {
+      setSecurityError(e instanceof Error ? e.message : "Fix fehlgeschlagen.");
+    } finally {
+      setFixLoading(null);
+    }
+  }
+
   const auditTotalPages = Math.ceil(auditTotal / AUDIT_PAGE_SIZE);
 
   return (
@@ -1215,7 +1235,7 @@ export default function AdminPage() {
                   </p>
                 )}
               </div>
-              <Button onClick={runSecurityAudit} disabled={securityLoading} size="sm">
+              <Button onClick={runSecurityAudit} disabled={securityLoading || fixLoading !== null} size="sm">
                 {securityLoading ? "Prüfe..." : "Jetzt prüfen"}
               </Button>
             </div>
@@ -1226,6 +1246,12 @@ export default function AdminPage() {
               </Alert>
             )}
 
+            {fixMessage && (
+              <Alert>
+                <AlertDescription className="text-green-700">{fixMessage}</AlertDescription>
+              </Alert>
+            )}
+
             {!securityAudit && !securityLoading && !securityError && (
               <div className="rounded-lg border border-dashed p-10 text-center text-sm text-muted-foreground">
                 Klicke auf &ldquo;Jetzt prüfen&rdquo; um den Security-Audit zu starten.
@@ -1240,47 +1266,81 @@ export default function AdminPage() {
               </div>
             )}
 
-            {securityAudit && !securityLoading && (
+            {securityAudit && !securityLoading && (() => {
-              <div className="space-y-2">
+              // Map check names to fix actions
-                {securityAudit.checks.map((check: SecurityCheck, i: number) => (
+              const fixActions: Record<string, { action: string; label: string }> = {
-                  <Card key={i}>
+                "Fail2ban":          { action: "install_fail2ban",      label: "Installieren & aktivieren" },
-                    <CardContent className="p-4 flex items-start gap-3">
+                "Firewall (nftables)": { action: "enable_firewall",     label: "Firewall aktivieren" },
-                      <span className={`mt-0.5 h-2.5 w-2.5 flex-shrink-0 rounded-full ${
+                "SSH Passwort-Auth": { action: "fix_ssh_password_auth", label: "Deaktivieren" },
-                        check.status === "ok" ? "bg-green-500" :
+                "SSH Root-Login":    { action: "fix_ssh_root_login",    label: "Auf prohibit-password setzen" },
-                        check.status === "warning" ? "bg-yellow-400" :
+              };
-                        "bg-red-500"
-                      }`} />
-                      <div className="flex-1 min-w-0">
-                        <div className="flex items-center gap-2">
-                          <span className="text-sm font-medium">{check.name}</span>
-                          <Badge
-                            variant={check.status === "ok" ? "default" : check.status === "warning" ? "secondary" : "destructive"}
-                            className={`text-xs ${check.status === "ok" ? "bg-green-100 text-green-800 hover:bg-green-100" : check.status === "warning" ? "bg-yellow-100 text-yellow-800 hover:bg-yellow-100" : ""}`}
-                          >
-                            {check.status === "ok" ? "OK" : check.status === "warning" ? "Warnung" : "Fehler"}
-                          </Badge>
-                        </div>
-                        <p className="text-xs text-muted-foreground mt-0.5 font-mono">{check.message}</p>
-                      </div>
-                    </CardContent>
-                  </Card>
-                ))}
 
-                {/* Summary */}
+              return (
-                <div className="mt-4 grid grid-cols-3 gap-3 text-center text-sm">
+                <div className="space-y-2">
-                  {[
+                  {securityAudit.checks.map((check: SecurityCheck, i: number) => {
-                    { label: "OK", color: "bg-green-50 text-green-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "ok").length },
+                    const fix = check.status !== "ok" ? fixActions[check.name] : undefined;
-                    { label: "Warnungen", color: "bg-yellow-50 text-yellow-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "warning").length },
+                    return (
-                    { label: "Fehler", color: "bg-red-50 text-red-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "error").length },
+                      <Card key={i}>
-                  ].map((s) => (
+                        <CardContent className="p-4 flex items-start gap-3">
-                    <div key={s.label} className={`rounded p-3 ${s.color}`}>
+                          <span className={`mt-1 h-2.5 w-2.5 flex-shrink-0 rounded-full ${
-                      <p className="text-2xl font-bold">{s.count}</p>
+                            check.status === "ok" ? "bg-green-500" :
-                      <p className="text-xs">{s.label}</p>
+                            check.status === "warning" ? "bg-yellow-400" : "bg-red-500"
-                    </div>
+                          }`} />
-                  ))}
+                          <div className="flex-1 min-w-0">
+                            <div className="flex items-center gap-2 flex-wrap">
+                              <span className="text-sm font-medium">{check.name}</span>
+                              <Badge
+                                variant={check.status === "ok" ? "default" : check.status === "warning" ? "secondary" : "destructive"}
+                                className={`text-xs ${check.status === "ok" ? "bg-green-100 text-green-800 hover:bg-green-100" : check.status === "warning" ? "bg-yellow-100 text-yellow-800 hover:bg-yellow-100" : ""}`}
+                              >
+                                {check.status === "ok" ? "OK" : check.status === "warning" ? "Warnung" : "Fehler"}
+                              </Badge>
+                            </div>
+                            <p className="text-xs text-muted-foreground mt-0.5 font-mono">{check.message}</p>
+                          </div>
+                          {fix && (
+                            <Button
+                              size="sm"
+                              variant="outline"
+                              className="flex-shrink-0 text-xs"
+                              disabled={fixLoading !== null}
+                              onClick={() => runFix(fix.action)}
+                            >
+                              {fixLoading === fix.action ? "Wird behoben..." : fix.label}
+                            </Button>
+                          )}
+                          {check.name === "HTTPS (TLS)" && check.status !== "ok" && (
+                            <a
+                              href="https://certbot.eff.org/instructions?os=debianbuster&tab=standard"
+                              target="_blank"
+                              rel="noopener noreferrer"
+                            >
+                              <Button size="sm" variant="outline" className="flex-shrink-0 text-xs">
+                                Anleitung
+                              </Button>
+                            </a>
+                          )}
+                        </CardContent>
+                      </Card>
+                    );
+                  })}
+
+                  {/* Summary */}
+                  <div className="mt-4 grid grid-cols-3 gap-3 text-center text-sm">
+                    {[
+                      { label: "OK", color: "bg-green-50 text-green-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "ok").length },
+                      { label: "Warnungen", color: "bg-yellow-50 text-yellow-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "warning").length },
+                      { label: "Fehler", color: "bg-red-50 text-red-700", count: securityAudit.checks.filter((c: SecurityCheck) => c.status === "error").length },
+                    ].map((s) => (
+                      <div key={s.label} className={`rounded p-3 ${s.color}`}>
+                        <p className="text-2xl font-bold">{s.count}</p>
+                        <p className="text-xs">{s.label}</p>
+                      </div>
+                    ))}
+                  </div>
                 </div>
-              </div>
+              );
-            )}
+            })()}
           </TabsContent>
 
           <TabsContent value="modules" className="mt-4">

src/lib/api.ts

@@ -520,3 +520,10 @@ export interface SecurityAuditResult {
 export async function getSecurityAudit(): Promise<SecurityAuditResult> {
   return request<SecurityAuditResult>("/api/admin/security/audit");
 }
+
+export async function fixSecurityIssue(action: string): Promise<{ message: string }> {
+  return request<{ message: string }>("/api/admin/security/fix", {
+    method: "POST",
+    body: JSON.stringify({ action }),
+  });
+}