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Azure Front Door's Web Application Firewall (WAF) provides extensive logging and telemetry to help you to understand how your WAF is performing and the actions it takes.
Front Door's WAF log is integrated with Azure Monitor. Azure Monitor enables you to track diagnostic information including WAF alerts and logs. You can configure WAF monitoring within the Front Door resource in the portal under the Diagnostics tab, through infrastructure as code approaches, or by using the Azure Monitor service directly.
Metrics
Azure Front Door automatically records metrics to help you to understand the behavior of your WAF.
To access your WAF's metrics:
- Sign in to the Azure portal and navigate to your Azure Front Door profile.
- Select the Monitoring/Metrics tab on the left.
- Add the WebApplicationFirewallRequestCount to track number of requests that match WAF rules.
Custom filters can be created based on action types and rule names. Metrics include requests with all actions except Log.
Logs and diagnostics
Azure Front Door's WAF provides detailed reporting on each request, and each threat that it detects. Logging is integrated with Azure's diagnostics logs and alerts by using Azure Monitor logs.
Logs aren't enabled by default. You need to explicitly enable logs. You can configure logs in the Azure portal by using the Diagnostic settings tab.
If logging is enabled and a WAF rule is triggered, any matching patterns are logged in plain text to help you analyze and debug the WAF policy behavior. You can use exclusions to fine tune rules and exclude any data that you want to be excluded from the logs. For more information, see Web application firewall exclusion lists in Azure Front Door.
Front Door provides two types of logs: access logs and WAF logs.
Access logs
The FrontDoorAccessLog includes all requests that go through Front Door. For more information on the Front Door access log, including the log schema, see Monitor metrics and logs in Azure Front Door.
The FrontdoorAccessLog includes all requests that go through Front Door. For more information on the Front Door access log, including the log schema, see Monitoring metrics and logs in Azure Front Door (classic).
The following example query returns the access log entries:
AzureDiagnostics| where ResourceProvider == "MICROSOFT.CDN" and Category == "FrontDoorAccessLog"AzureDiagnostics| where ResourceType == "FRONTDOORS" and Category == "FrontdoorAccessLog"The following shows an example log entry:
{ "time": "2020-06-09T22:32:17.8383427Z", "category": "FrontDoorAccessLog", "operationName": "Microsoft.Cdn/Profiles/AccessLog/Write", "properties": { "trackingReference": "08Q3gXgAAAAAe0s71BET/QYwmqtpHO7uAU0pDRURHRTA1MDgANjMxNTAwZDAtOTRiNS00YzIwLTljY2YtNjFhNzMyOWQyYTgy", "httpMethod": "GET", "httpVersion": "2.0", "requestUri": "https://wafdemofrontdoorwebapp.azurefd.net:443/?q=%27%20or%201=1", "requestBytes": "715", "responseBytes": "380", "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4157.0 Safari/537.36 Edg/85.0.531.1", "clientIp": "xxx.xxx.xxx.xxx", "socketIp": "xxx.xxx.xxx.xxx", "clientPort": "52097", "timeTaken": "0.003", "securityProtocol": "TLS 1.2", "routingRuleName": "WAFdemoWebAppRouting", "rulesEngineMatchNames": [], "backendHostname": "wafdemowebappuscentral.azurewebsites.net:443", "sentToOriginShield": false, "httpStatusCode": "403", "httpStatusDetails": "403", "pop": "SJC", "cacheStatus": "CONFIG_NOCACHE" }}{ "time": "2020-06-09T22:32:17.8383427Z", "category": "FrontdoorAccessLog", "operationName": "Microsoft.Network/FrontDoor/AccessLog/Write", "properties": { "trackingReference": "08Q3gXgAAAAAe0s71BET/QYwmqtpHO7uAU0pDRURHRTA1MDgANjMxNTAwZDAtOTRiNS00YzIwLTljY2YtNjFhNzMyOWQyYTgy", "httpMethod": "GET", "httpVersion": "2.0", "requestUri": "https://wafdemofrontdoorwebapp.azurefd.net:443/?q=%27%20or%201=1", "requestBytes": "715", "responseBytes": "380", "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4157.0 Safari/537.36 Edg/85.0.531.1", "clientIp": "xxx.xxx.xxx.xxx", "socketIp": "xxx.xxx.xxx.xxx", "clientPort": "52097", "timeTaken": "0.003", "securityProtocol": "TLS 1.2", "routingRuleName": "WAFdemoWebAppRouting", "rulesEngineMatchNames": [], "backendHostname": "wafdemowebappuscentral.azurewebsites.net:443", "sentToOriginShield": false, "httpStatusCode": "403", "httpStatusDetails": "403", "pop": "SJC", "cacheStatus": "CONFIG_NOCACHE" }}WAF logs
The FrontDoorWebApplicationFirewallLog includes requests that match a WAF rule.
The FrontdoorWebApplicationFirewallLog includes any request that matches a WAF rule.
The following table shows the values logged for each request:
| Property | Description |
|---|---|
| Action | Action taken on the request. Logs include requests with all actions. Actions are:
|
| ClientIP | The IP address of the client that made the request. If there was an X-Forwarded-For header in the request, the client IP address is taken from that header field instead. |
| ClientPort | The IP port of the client that made the request. |
| Details | Additional details on the request, including any threats that were detected. matchVariableName: HTTP parameter name of the request matched, for example, header names (up to 100 characters maximum). matchVariableValue: Values that triggered the match (up to 100 characters maximum). |
| Host | The Host header of the request. |
| Policy | The name of the WAF policy that processed the request. |
| PolicyMode | Operations mode of the WAF policy. Possible values are Prevention and Detection. |
| RequestUri | Full URI of the request. |
| RuleName | The name of the WAF rule that the request matched. |
| SocketIP | The source IP address seen by WAF. This IP address is based on the TCP session, and does not consider any request headers. |
| TrackingReference | The unique reference string that identifies a request served by Front Door. This value is sent to the client in the X-Azure-Ref response header. Use this field when searching for a specific request in the log. |
The following example query shows the requests that were blocked by the Front Door WAF:
AzureDiagnostics | where ResourceProvider == "MICROSOFT.CDN" and Category == "FrontDoorWebApplicationFirewallLog" | where action_s == "Block" AzureDiagnostics| where ResourceType == "FRONTDOORS" and Category == "FrontdoorWebApplicationFirewallLog"| where action_s == "Block"The following shows an example log entry, including the reason that the request was blocked:
{ "time": "2020-06-09T22:32:17.8376810Z", "category": "FrontdoorWebApplicationFirewallLog", "operationName": "Microsoft.Cdn/Profiles/Write", "properties": { "clientIP": "xxx.xxx.xxx.xxx", "clientPort": "52097", "socketIP": "xxx.xxx.xxx.xxx", "requestUri": "https://wafdemofrontdoorwebapp.azurefd.net:443/?q=%27%20or%201=1", "ruleName": "Microsoft_DefaultRuleSet-1.1-SQLI-942100", "policy": "WafDemoCustomPolicy", "action": "Block", "host": "wafdemofrontdoorwebapp.azurefd.net", "trackingReference": "08Q3gXgAAAAAe0s71BET/QYwmqtpHO7uAU0pDRURHRTA1MDgANjMxNTAwZDAtOTRiNS00YzIwLTljY2YtNjFhNzMyOWQyYTgy", "policyMode": "prevention", "details": { "matches": [ { "matchVariableName": "QueryParamValue:q", "matchVariableValue": "' or 1=1" } ] } }}{ "time": "2020-06-09T22:32:17.8376810Z", "category": "FrontdoorWebApplicationFirewallLog", "operationName": "Microsoft.Network/FrontDoorWebApplicationFirewallLog/Write", "properties": { "clientIP": "xxx.xxx.xxx.xxx", "clientPort": "52097", "socketIP": "xxx.xxx.xxx.xxx", "requestUri": "https://wafdemofrontdoorwebapp.azurefd.net:443/?q=%27%20or%201=1", "ruleName": "Microsoft_DefaultRuleSet-1.1-SQLI-942100", "policy": "WafDemoCustomPolicy", "action": "Block", "host": "wafdemofrontdoorwebapp.azurefd.net", "trackingReference": "08Q3gXgAAAAAe0s71BET/QYwmqtpHO7uAU0pDRURHRTA1MDgANjMxNTAwZDAtOTRiNS00YzIwLTljY2YtNjFhNzMyOWQyYTgy", "policyMode": "prevention", "details": { "matches": [ { "matchVariableName": "QueryParamValue:q", "matchVariableValue": "' or 1=1" } ] } }}Next steps
- Learn more about Front Door.
