docs(audit): add SIEM configuration to docs, .env.demo, and settings metadata

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

.env.demo

@@ -96,6 +96,24 @@ MAX_UPLOAD_SIZE=1073741824
 # Allowed request headers (use * to allow all)
 # CORS_ALLOWED_HEADERS=*
 
+# **Rate Limiting** (see SECURITY_AUDIT.md and docs/API.md)
+
+# **Audit Logging & SIEM Integration** (see docs/ConfigurationGuide.md#audit-logging)
+# Enable HTTP request audit logging middleware
+AUDIT_LOGGING_ENABLED=true
+# Include client IP in audit log entries (disable for GDPR-sensitive deployments)
+AUDIT_LOG_INCLUDE_CLIENT_IP=true
+
+# Forward audit events to an external SIEM system (Syslog, Splunk, Logstash, Grafana, etc.)
+# AUDIT_SIEM_ENABLED=false
+# AUDIT_SIEM_TRANSPORT=syslog          # syslog | http
+# AUDIT_SIEM_SYSLOG_HOST=localhost
+# AUDIT_SIEM_SYSLOG_PORT=514
+# AUDIT_SIEM_SYSLOG_PROTOCOL=udp       # udp | tcp
+# AUDIT_SIEM_HTTP_URL=                  # e.g. https://splunk:8088/services/collector/event
+# AUDIT_SIEM_HTTP_TOKEN=                # Bearer / HEC token
+# AUDIT_SIEM_HTTP_CUSTOM_HEADERS=       # Comma-separated Key:Value pairs
+
 # **Rate Limiting** (see SECURITY_AUDIT.md and docs/API.md)
 # Protects against DoS attacks and API abuse by limiting request rates per IP/user
 # Enabled by default - highly recommended for production

app/utils/settings_service.py

@@ -2065,6 +2065,78 @@ SETTING_METADATA = {
         "required": False,
         "restart_required": True,
     },
+    "audit_siem_enabled": {
+        "category": "Security",
+        "description": "Enable forwarding of audit events to an external SIEM system (Syslog, Splunk, Logstash, etc.).",
+        "type": "boolean",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_transport": {
+        "category": "Security",
+        "description": (
+            "Transport used to forward audit events. 'syslog' sends RFC 5424 messages over UDP/TCP. "
+            "'http' sends JSON POST payloads to a webhook URL (Splunk HEC, Logstash, Grafana Loki, etc.)."
+        ),
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+        "options": ["syslog", "http"],
+    },
+    "audit_siem_syslog_host": {
+        "category": "Security",
+        "description": "Hostname or IP of the syslog receiver.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_syslog_port": {
+        "category": "Security",
+        "description": "Port of the syslog receiver. Default: 514.",
+        "type": "integer",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_syslog_protocol": {
+        "category": "Security",
+        "description": "Protocol for syslog transport: 'udp' or 'tcp'. Default: udp.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+        "options": ["udp", "tcp"],
+    },
+    "audit_siem_http_url": {
+        "category": "Security",
+        "description": (
+            "HTTP endpoint URL for SIEM webhook delivery. Supports Splunk HEC, "
+            "Logstash HTTP input, Grafana Loki push API, or any JSON-accepting endpoint."
+        ),
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_http_token": {
+        "category": "Security",
+        "description": "Bearer / HEC token included in the Authorization header of SIEM HTTP requests.",
+        "type": "string",
+        "sensitive": True,
+        "required": False,
+        "restart_required": False,
+    },
+    "audit_siem_http_custom_headers": {
+        "category": "Security",
+        "description": "Comma-separated 'Key:Value' pairs of extra headers for SIEM HTTP requests.",
+        "type": "string",
+        "sensitive": False,
+        "required": False,
+        "restart_required": False,
+    },
     # Rate Limiting
     "rate_limiting_enabled": {
         "category": "Security",

docs/ConfigurationGuide.md

@@ -398,6 +398,61 @@ default overage buffer applied across all plans.
 
 DocuElevate supports HTTP security headers to improve browser-side security. **These headers are disabled by default** since most deployments use a reverse proxy (Traefik, Nginx, etc.) that already adds them. Enable only if deploying directly without a reverse proxy. See [Deployment Guide - Security Headers](DeploymentGuide.md#security-headers) for detailed configuration examples.
 
+### Audit Logging
+
+DocuElevate provides comprehensive audit logging that records significant actions (logins, document CRUD, settings changes) to an append-only database table. Every entry captures the timestamp, user, action, resource, client IP, and optional JSON details.
+
+| **Variable**                   | **Description**                                                                                   | **Default** |
+|--------------------------------|---------------------------------------------------------------------------------------------------|-------------|
+| `AUDIT_LOGGING_ENABLED`       | Enable the HTTP request audit-logging middleware.                                                  | `true`      |
+| `AUDIT_LOG_INCLUDE_CLIENT_IP` | Include the client IP address in audit log entries. Disable for GDPR-sensitive deployments.       | `true`      |
+
+#### SIEM Integration
+
+Audit events can be forwarded in real time to external SIEM systems for centralised monitoring, alerting, and long-term retention. Two transports are supported:
+
+* **Syslog** – RFC 5424 structured-data messages over UDP or TCP. Works with rsyslog, syslog-ng, Graylog, Datadog, etc.
+* **HTTP** – JSON POST payloads compatible with Splunk HEC, Logstash HTTP input, Grafana Loki push API, and any generic webhook.
+
+| **Variable**                        | **Description**                                                                                   | **Default**   |
+|-------------------------------------|---------------------------------------------------------------------------------------------------|---------------|
+| `AUDIT_SIEM_ENABLED`               | Enable forwarding of audit events to an external SIEM system.                                     | `false`       |
+| `AUDIT_SIEM_TRANSPORT`             | Transport: `syslog` or `http`.                                                                    | `syslog`      |
+| `AUDIT_SIEM_SYSLOG_HOST`           | Hostname or IP of the syslog receiver.                                                            | `localhost`   |
+| `AUDIT_SIEM_SYSLOG_PORT`           | Port of the syslog receiver.                                                                      | `514`         |
+| `AUDIT_SIEM_SYSLOG_PROTOCOL`       | Protocol for syslog: `udp` or `tcp`.                                                              | `udp`         |
+| `AUDIT_SIEM_HTTP_URL`              | HTTP endpoint URL for SIEM delivery (e.g. Splunk HEC, Logstash, Loki).                           | *(empty)*     |
+| `AUDIT_SIEM_HTTP_TOKEN`            | Bearer / HEC token for the SIEM HTTP endpoint.                                                    | *(empty)*     |
+| `AUDIT_SIEM_HTTP_CUSTOM_HEADERS`   | Comma-separated `Key:Value` extra headers for SIEM HTTP requests.                                 | *(empty)*     |
+
+**Example – Syslog to rsyslog:**
+
+```bash
+AUDIT_SIEM_ENABLED=true
+AUDIT_SIEM_TRANSPORT=syslog
+AUDIT_SIEM_SYSLOG_HOST=syslog.internal.example.com
+AUDIT_SIEM_SYSLOG_PORT=514
+AUDIT_SIEM_SYSLOG_PROTOCOL=udp
+```
+
+**Example – Splunk HEC:**
+
+```bash
+AUDIT_SIEM_ENABLED=true
+AUDIT_SIEM_TRANSPORT=http
+AUDIT_SIEM_HTTP_URL=https://splunk.example.com:8088/services/collector/event
+AUDIT_SIEM_HTTP_TOKEN=your-hec-token
+```
+
+**Example – Logstash HTTP input:**
+
+```bash
+AUDIT_SIEM_ENABLED=true
+AUDIT_SIEM_TRANSPORT=http
+AUDIT_SIEM_HTTP_URL=https://logstash.example.com:8080
+AUDIT_SIEM_HTTP_TOKEN=
+```
+
 ### Rate Limiting
 
 DocuElevate implements rate limiting to protect against DoS attacks and API abuse. **Rate limiting is enabled by default** and uses Redis for distributed rate limiting across multiple workers.