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Bot Control Rules  选择 CAPTCHA




webacl-alb-api-001默认规则:AWS-AWSManagedRulesBotControlRuleSet规则如下

Code Block
themeRDark
{
  "Name": "AWS-AWSManagedRulesBotControlRuleSet",
  "Priority": 0,
  "Statement": {
    "ManagedRuleGroupStatement": {
      "VendorName": "AWS",
      "Name": "AWSManagedRulesBotControlRuleSet",
      "ScopeDownStatement": {
        "AndStatement": {
          "Statements": [
            {
              "ByteMatchStatement": {
                "SearchString": "/waf/query",
                "FieldToMatch": {
                  "UriPath": {}
                },
                "TextTransformations": [
                  {
                    "Priority": 0,
                    "Type": "LOWERCASE"
                  }
                ],
                "PositionalConstraint": "EXACTLY"
              }
            },
            {
              "NotStatement": {
                "Statement": {
                  "ByteMatchStatement": {
                    "SearchString": "POST",
                    "FieldToMatch": {
                      "Method": {}
                    },
                    "TextTransformations": [
                      {
                        "Priority": 0,
                        "Type": "NONE"
                      }
                    ],
                    "PositionalConstraint": "EXACTLY"
                  }
                }
              }
            }
          ]
        }
      },
      "ManagedRuleGroupConfigs": [
        {
          "AWSManagedRulesBotControlRuleSet": {
            "InspectionLevel": "TARGETED",
            "EnableMachineLearning": true
          }
        }
      ],
      "RuleActionOverrides": [
        {
          "Name": "SignalNonBrowserUserAgent",
          "ActionToUse": {
            "Captcha": {}
          }
        },
        {
          "Name": "TGT_VolumetricIpTokenAbsent",
          "ActionToUse": {
            "Captcha": {}
          }
        }
      ]
    }
  },
  "OverrideAction": {
    "None": {}
  },
  "VisibilityConfig": {
    "SampledRequestsEnabled": true,
    "CloudWatchMetricsEnabled": true,
    "MetricName": "AWS-AWSManagedRulesBotControlRuleSet"
  }
}



Webacl-alb-api-001自定义规则:

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{
  "Name": "Block-Requests-With-Missing-Or-Rejected-Token-Label",
  "Priority": 1,
  "Statement": {
    "AndStatement": {
      "Statements": [
        {
          "OrStatement": {
            "Statements": [
              {
                "LabelMatchStatement": {
                  "Scope": "LABEL",
                  "Key": "awswaf:managed:token:absent"
                }
              },
              {
                "LabelMatchStatement": {
                  "Scope": "LABEL",
                  "Key": "awswaf:managed:token:rejected"
                }
              }
            ]
          }
        },
        {
          "NotStatement": {
            "Statement": {
              "ByteMatchStatement": {
                "SearchString": "POST",
                "FieldToMatch": {
                  "Method": {}
                },
                "TextTransformations": [
                  {
                    "Priority": 0,
                    "Type": "NONE"
                  }
                ],
                "PositionalConstraint": "EXACTLY"
              }
            }
          }
        }
      ]
    }
  },
  "Action": {
    "Block": {}
  },
  "VisibilityConfig": {
    "SampledRequestsEnabled": true,
    "CloudWatchMetricsEnabled": true,
    "MetricName": "Block-Requests-With-Missing-Or-Rejected-Token-Label"
  }
}

...

访问 Web 前端,打开浏览器开发者模式。可以看到,页面在初始化后自动与 WAF 后台进行交互,获取了jsapi.js 并进行静默计算得到 token。在发起 query 请求后,会自动在 cookie header 中带上 aws-waf-token。WAF 后台的 Bot control Rule 进行 token 校验成功后,流量被发送到 ALB。Echo-Server 会把发送的请求原样返回,可以看到请求中包含了 token 信息。

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2、增加根据 Token 判断阻断的 WAF Rule

对于 Request 中不带有 token,或者 token 无效,我们希望 WAF 进行阻止的操作。需要做如下配置。

从流程上看,token 无效的请求,AWSManagedRuleBotControlRuleSet 会给这条 Request 加上 Label,用于表示 token 不存在或 token 无效。我们可以继续配置自定义规则,如果 request 包含特定 label,则说明请求来自非法客户端,进行阻断。

Awswaf:managed:token:absent,包含这个 label 说明 token 不存在

Awswaf:managed:token:rejected,包含这个 label 说明 token 无效

增加 Custom Rule,如果请求中包含上述 Label,则 Block

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增加 Custom Rule,如果请求的 token 无效,则 Block。以下是等效配置的 JSON 描述:

Image Removed

现在有三条 Rule 作用在 WAF ACL 上:

Image Removed

3、观察不带 Token 的请求访问业务后端的情况

修改 Web 前端,使用 JS 原生 fetch(),不带 token 发送请求给业务后端。

...

themeRDark

...

Image Added


请求头和报文

Code Block
themeRDark
POST
	http://api001.bosicloud.one/waf/query
状态
200
版本HTTP/1.1
传输485 字节(大小 98 字节)
Referrer 策略strict-origin-when-cross-origin
DNS 解析系统


POST /waf/query HTTP/1.1
Host: api001.bosicloud.one
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:126.0) Gecko/20100101 Firefox/126.0
Accept: */*
Accept-Language: zh-CN,zh;q=0.8,zh-TW;q=0.7,zh-HK;q=0.5,en-US;q=0.3,en;q=0.2
Accept-Encoding: gzip, deflate
Referer: http://web001.bosicloud.one/
Origin: http://web001.bosicloud.one
Connection: keep-alive
Priority: u=4
Content-Length: 0



响应头和报文

Code Block
HTTP/1.1 200 
Date: Thu, 13 Jun 2024 04:38:54 GMT
Content-Type: application/json;charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Origin
Vary: Access-Control-Request-Method
Vary: Access-Control-Request-Headers
Access-Control-Allow-Origin: http://web001.bosicloud.one
Access-Control-Expose-Headers: X-Sms-Portal-Identity-Token
Access-Control-Allow-Credentials: true



{"msg":"success","code":0,"data":{"waf-query":"ok.","database":"ok.","redis":"ok.","status":"ok"}}




2、增加根据 Token 判断阻断的 WAF Rule

对于 Request 中不带有 token,或者 token 无效,我们希望 WAF 进行阻止的操作。需要做如下配置。

从流程上看,token 无效的请求,AWSManagedRuleBotControlRuleSet 会给这条 Request 加上 Label,用于表示 token 不存在或 token 无效。我们可以继续配置自定义规则,如果 request 包含特定 label,则说明请求来自非法客户端,进行阻断。

Awswaf:managed:token:absent,包含这个 label 说明 token 不存在

Awswaf:managed:token:rejected,包含这个 label 说明 token 无效

增加 Custom Rule,如果请求中包含上述 Label,则 Block


Image Added



Image Added


增加 Custom Rule,如果请求的 token 无效,则 Block。以下是等效配置的 JSON 描述:

Image Added


现在有三条 Rule 作用在 WAF ACL 上:

Image Added



3、观察不带 Token 的请求访问业务后端的情况


修改 Web 前端,使用 JS 原生 fetch(),不带 token 发送请求给业务后端。

Code Block
themeRDark
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Waf Captcha Test</title>
	<script type="text/javascript" src="https://73f53964XXX.ap-southeast-1.captcha-sdk.awswaf.com/73f53964XXXX/jsapi.js" defer></script>
</head>

<body>

<h1>Login Page</h1>

<p>Click on the below button to login</p>

<button onclick="userAction()">Login</button>

	
<script type="text/javascript">
	const apiURL = 'http://api001.bosicloud.one/waf/query';

    function showMyCaptcha() {
        const container = document.getElementById('container');
        AwsWafCaptcha.renderCaptcha(container, {
          apiKey: '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_0_1',
            async function login(){
onSuccess: successFunction,
            let user = {
onError: errorFunction,
        });
    }

    function name: 'username',successFunction() {
      const container = document.getElementById('container');
      surname:container.innerHTML = 'surname';
      AwsWafIntegration.fetch(apiURL, {}).then(response    };
   => {
        const responseresponse.json().then(myJson => await{ fetch('https://yourdomain.com/waf/query',{renderResponse(myJson) });
      });
    }

     method: 'POST',function errorFunction(error) {
       console.log(error);
    }

     headers:function renderResponse(json) {
        if (json) {
           'Content-Type': 'application/json'
        container.innerHTML = "Result: The request resulted is Success.";
        }, else {
            container.innerHTML = "Result: body: JSON.stringify(user)
   The request resulted is Error.";
        });
    }

    function   userAction() {
		const responseTextcontainer = await responsedocument.textgetElementById('container');
		container.innerHTML = '';
           document.getElementById("display").innerText = responseText
           console.log(responseText)
    
		AwsWafIntegration.fetch(apiURL,{method: 'POST'}).then(response => {
			if ( response.status == 405) {
				showMyCaptcha();
			} else {
				response.json().then(myJson => { renderResponse(myJson) });
			}
		});
    }
   </script>

<p>Hello WAF!</p>
<div id='displaycontainer'></div>

</body>
</html>


通过 Chrome 浏览器开发者模式可以看到,由于请求不带 token,请求被 WAF 所拒绝。

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