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chaitin-waf

Apache APISIX

API Gateway

Plugin

WAF

This document contains basic information about the Apache APISIX `chaitin-waf` plugin.

Description

After enabling the chaitin-waf plugin, the traffic will be forwarded to the Chaitin WAF service for detection and prevention of various web application attacks, ensuring the security of the application and user data.

Response Headers

Depending on the plugin configuration, it is optional to add additional response headers.

The response headers are listed below:

X-APISIX-CHAITIN-WAF: Whether APISIX forwards the request to the WAF server.
- yes: forwarded
- no: not forwarded
- unhealthy: matches the match variables, but no WAF server is available.
- err: an error occurred during the execution of the plugin. Also includes the X-APISIX-CHAITIN-WAF-ERROR header.
- waf-err: error while interacting with the WAF server. Also includes the X-APISIX-CHAITIN-WAF-ERROR header.
- timeout: request to the WAF server timed out.
X-APISIX-CHAITIN-WAF-ERROR: Debug header. Contains WAF error message.
X-APISIX-CHAITIN-WAF-TIME: The time in milliseconds that APISIX spent interacting with WAF.
X-APISIX-CHAITIN-WAF-STATUS: The status code returned to APISIX by the WAF server.
X-APISIX-CHAITIN-WAF-ACTION: The action returned to APISIX by the WAF server.
- pass: request valid and passed.
- reject: request rejected by WAF service.
X-APISIX-CHAITIN-WAF-SERVER: Debug header. Indicates which WAF server was selected.

Plugin Metadata

Name	Type	Required	Default value	Description
nodes	array(object)	true		A list of addresses for the Chaitin SafeLine WAF service.
nodes[0].host	string	true		The address of Chaitin SafeLine WAF service. Supports IPv4, IPv6, Unix Socket, etc.
nodes[0].port	integer	false	80	The port of the Chaitin SafeLine WAF service.
mode	string	false	block	The global default mode if a Route doesn't specify its own: `off`, `monitor`, or `block`.
config	object	false		WAF configuration defaults if none are specified on the Route.
config.connect_timeout	integer	false	1000	Connect timeout, in milliseconds.
config.send_timeout	integer	false	1000	Send timeout, in milliseconds.
config.read_timeout	integer	false	1000	Read timeout, in milliseconds.
config.req_body_size	integer	false	1024	Request body size, in KB.
config.keepalive_size	integer	false	256	Maximum concurrent idle connections to the SafeLine WAF detection service.
config.keepalive_timeout	integer	false	60000	Idle connection timeout, in milliseconds.
config.real_client_ip	boolean	false	true	Specifies whether to use the `X-Forwarded-For` as the client IP (if present). If `false`, uses the direct client IP from the connection.

:::note You can fetch the admin_key from config.yaml and save to an environment variable with the following command:

admin_key=$(yq '.deployment.admin.admin_key[0].key' conf/config.yaml | sed 's/"//g')

:::

curl http://127.0.0.1:9180/apisix/admin/plugin_metadata/chaitin-waf -H "X-API-KEY: $admin_key" -X PUT -d '
{
  "nodes": [
    {
      "host": "unix:/path/to/safeline/resources/detector/snserver.sock",
      "port": 8000
    }
  ],
  "mode": "block",
  "config": {
    "real_client_ip": true
  }
}'

Attributes

Name	Type	Required	Default value	Description
mode	string	false	block	Determines how the plugin behaves for matched requests. Valid values are `off`, `monitor`, or `block`. When set to `off`, the plugin skips WAF checks. In `monitor` mode, the plugin logs potential blocks without actually blocking the request. In `block` mode, the plugin enforces blocks as determined by the WAF service.
match	array[object]	false		A list of matching rules. The plugin evaluates these rules to decide whether to perform the WAF check on a request. If empty, all requests are processed.
match.vars	array[array]	false		List of variables used for matching requests. Each rule is specified as `[variable, operator, value]` (for example, `["http_waf", "==", "true"]`). These variables refer to NGINX internal variables. For supported operators, see lua-resty-expr.
append_waf_resp_header	bool	false	true	Determines whether the plugin adds WAF-related response headers (such as `X-APISIX-CHAITIN-WAF`, `X-APISIX-CHAITIN-WAF-ACTION`, etc.) to the response.
append_waf_debug_header	bool	false	false	Determines whether debugging headers (such as `X-APISIX-CHAITIN-WAF-ERROR` and `X-APISIX-CHAITIN-WAF-SERVER`) are added. Effective only when `append_waf_resp_header` is enabled.
config	object	false		Provides route-specific configuration for the Chaitin SafeLine WAF service. Settings here override the corresponding metadata defaults when specified.
config.connect_timeout	integer	false	1000	The connect timeout for the WAF server, in milliseconds.
config.send_timeout	integer	false	1000	The send timeout for transmitting data to the WAF server, in milliseconds.
config.read_timeout	integer	false	1000	The read timeout for receiving data from the WAF server, in milliseconds.
config.req_body_size	integer	false	1024	The maximum allowed request body size, in KB.
config.keepalive_size	integer	false	256	The maximum number of idle connections to the WAF detection service that can be maintained concurrently.
config.keepalive_timeout	integer	false	60000	The idle connection timeout for the WAF service, in milliseconds.
config.real_client_ip	boolean	false	true	Specifies whether to determine the client IP from the `X-Forwarded-For` header. If set to `false`, the plugin uses the direct client IP from the connection.

Below is a sample Route configuration that uses:

httpbun.org as the upstream backend.
mode set to monitor, so the plugin only logs potential blocks.
A matching rule that triggers the plugin when the custom header waf: true is set.
An override to disable the real client IP logic by setting config.real_client_ip to false.

curl http://127.0.0.1:9180/apisix/admin/routes/1 \
  -H "X-API-KEY: $admin_key" \
  -X PUT -d '
{
   "uri": "/*",
   "plugins": {
       "chaitin-waf": {
           "mode": "monitor",
           "match": [
                {
                    "vars": [
                        ["http_waf", "==", "true"]
                    ]
                }
            ],
           "config": {
               "real_client_ip": false
           },
           "append_waf_resp_header": true,
           "append_waf_debug_header": false
       }
    },
   "upstream": {
       "type": "roundrobin",
       "nodes": {
           "httpbun.org:80": 1
       }
   }
}'

Test Plugin

With the sample configuration described above (including your chosen mode and real_client_ip settings), the plugin behaves as follows:

If the match condition is not satisfied (for example, waf: true is missing), the request proceeds normally without contacting the WAF. You can observe:

curl -H "Host: httpbun.org" http://127.0.0.1:9080/get -i

HTTP/1.1 200 OK
Content-Type: application/json
Content-Length: 408
Connection: keep-alive
X-APISIX-CHAITIN-WAF: no
Date: Wed, 19 Jul 2023 09:30:42 GMT
X-Powered-By: httpbun/3c0dc05883dd9212ac38b04705037d50b02f2596
Server: APISIX/3.3.0

{
  "args": {},
  "headers": {
    "Accept": "*/*",
    "Connection": "close",
    "Host": "httpbun.org",
    "User-Agent": "curl/8.1.2",
    "X-Forwarded-For": "127.0.0.1",
    "X-Forwarded-Host": "httpbun.org",
    "X-Forwarded-Port": "9080",
    "X-Forwarded-Proto": "http",
    "X-Real-Ip": "127.0.0.1"
  },
  "method": "GET",
  "origin": "127.0.0.1, 122.231.76.178",
  "url": "http://httpbun.org/get"
}

Potential injection requests (e.g., containing SQL snippets) are forwarded unmodified if they do not meet the plugin’s match rules, and might result in a 404 Not Found or other response from the upstream:

  curl -H "Host: httpbun.org" http://127.0.0.1:9080/getid=1%20AND%201=1 -i

  HTTP/1.1 404 Not Found
  Content-Type: text/plain; charset=utf-8
  Content-Length: 19
  Connection: keep-alive
  X-APISIX-CHAITIN-WAF: no
  Date: Wed, 19 Jul 2023 09:30:28 GMT
  X-Content-Type-Options: nosniff
  X-Powered-By: httpbun/3c0dc05883dd9212ac38b04705037d50b02f2596
  Server: APISIX/3.3.0

  404 page not found

Matching safe requests (those that satisfy match.vars, such as -H "waf: true") are checked by the WAF. If deemed harmless, you see:

  curl -H "Host: httpbun.org" -H "waf: true" http://127.0.0.1:9080/get -i

  HTTP/1.1 200 OK
  Content-Type: application/json
  Content-Length: 427
  Connection: keep-alive
  X-APISIX-CHAITIN-WAF-TIME: 2
  X-APISIX-CHAITIN-WAF-STATUS: 200
  X-APISIX-CHAITIN-WAF: yes
  X-APISIX-CHAITIN-WAF-ACTION: pass
  Date: Wed, 19 Jul 2023 09:29:58 GMT
  X-Powered-By: httpbun/3c0dc05883dd9212ac38b04705037d50b02f2596
  Server: APISIX/3.3.0

  {
    "args": {},
    "headers": {
      "Accept": "*/*",
      "Connection": "close",
      "Host": "httpbun.org",
      "User-Agent": "curl/8.1.2",
      "Waf": "true",
      "X-Forwarded-For": "127.0.0.1",
      "X-Forwarded-Host": "httpbun.org",
      "X-Forwarded-Port": "9080",
      "X-Forwarded-Proto": "http",
      "X-Real-Ip": "127.0.0.1"
    },
    "method": "GET",
    "origin": "127.0.0.1, 122.231.76.178",
    "url": "http://httpbun.org/get"
  }

Suspicious requests that meet the plugin’s match rules and are flagged by the WAF are typically rejected with a 403 status, along with headers that include X-APISIX-CHAITIN-WAF-ACTION: reject. For example:

  curl -H "Host: httpbun.org" -H "waf: true" http://127.0.0.1:9080/getid=1%20AND%201=1 -i

  HTTP/1.1 403 Forbidden
  Date: Wed, 19 Jul 2023 09:29:06 GMT
  Content-Type: text/plain; charset=utf-8
  Transfer-Encoding: chunked
  Connection: keep-alive
  X-APISIX-CHAITIN-WAF: yes
  X-APISIX-CHAITIN-WAF-TIME: 2
  X-APISIX-CHAITIN-WAF-ACTION: reject
  X-APISIX-CHAITIN-WAF-STATUS: 403
  Server: APISIX/3.3.0
  Set-Cookie: sl-session=UdywdGL+uGS7q8xMfnJlbQ==; Domain=; Path=/; Max-Age=86400

  {"code": 403, "success":false, "message": "blocked by Chaitin SafeLine Web Application Firewall", "event_id": "51a268653f2c4189bfa3ec66afbcb26d"}

Delete Plugin

To remove the chaitin-waf plugin, you can delete the corresponding JSON configuration from the Plugin configuration. APISIX will automatically reload and you do not have to restart for this to take effect:

$ curl http://127.0.0.1:9180/apisix/admin/routes/1 -H "X-API-KEY: $admin_key" -X PUT -d '
{
   "uri": "/*",
   "upstream": {
       "type": "roundrobin",
       "nodes": {
           "httpbun.org:80": 1
       }
   }
}'

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