{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/29283b22-a1c0-4d16-b0a9-3460b655a46a')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/29283b22-a1c0-4d16-b0a9-3460b655a46a')]",
      "properties": {
        "alertRuleTemplateName": "29283b22-a1c0-4d16-b0a9-3460b655a46a",
        "customDetails": null,
        "description": "'This query uses various log sources having user agent data to look for log4j CVE-2021-44228 exploitation attempt based on user agent pattern.\nLog4j is an open-source Apache logging library that is used in many Java-based applications. The regex and the string matching look for the most common attacks. This might not be comprehensive to detect every possible user agent variation.\n Reference: https://msrc-blog.microsoft.com/2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/'\n",
        "displayName": "User agent search for log4j exploitation attempt",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "Url",
                "identifier": "Url"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SourceIP",
                "identifier": "Address"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Account",
                "identifier": "Name"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Apache%20Log4j%20Vulnerability%20Detection/Analytic%20Rules/UserAgentSearch_log4j.yaml",
        "query": "let UserAgentString = dynamic ([\"${jndi:ldap:/\", \"${jndi:rmi:/\", \"${jndi:ldaps:/\", \"${jndi:dns:/\", \"${jndi:iiop:/\",\"${jndi:\",\"${jndi:nds:/\",\"${jndi:corba/\"]);\nlet UARegexMinimalString=dynamic(['{','%7b', '%7B']);\nlet UARegex = @'(\\\\$|%24)(\\\\{|%7B)([^jJ]*[jJ])([^nN]*[nN])([^dD]*[dD])([^iI]*[iI])(:|%3A|\\\\$|%24|}|%7D)';\n(union isfuzzy=true\n(OfficeActivity\n| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = ClientIP, Account = UserId, Type, Operation\n),\n(AzureDiagnostics\n| where Category in (\"FrontdoorWebApplicationFirewallLog\", \"FrontdoorAccessLog\", \"ApplicationGatewayFirewallLog\", \"ApplicationGatewayAccessLog\")\n| where userAgent_s has_any (UserAgentString) or userAgent_s matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = userAgent_s, SourceIP = column_ifexists(\"clientIp_s\",clientIP_s), Type, column_ifexists(\"originalHost_s\",host_s), Url = requestUri_s, HttpStatus = column_ifexists(\"httpStatusDetails_s\",httpStatus_d), column_ifexists(\"trackingReference_s\",transactionId_g), ruleName_s, ResourceType, ResourceId\n),\n(\nW3CIISLog\n| where csUserAgent has_any (UserAgentString) or csUserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = csUserAgent, SourceIP = cIP, Account = csUserName, Type, sSiteName, csMethod, Url = csUriStem\n),\n(\nAWSCloudTrail\n| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = SourceIpAddress, Account = UserIdentityUserName, Type, EventName\n),\n(SigninLogs\n| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail),    AppDisplayName, ClientAppUsed\n),\n(AADNonInteractiveUserSignInLogs \n| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail), AppDisplayName, ClientAppUsed\n),\n(_Im_WebSession (httpuseragent_has_any=array_concat(UserAgentString,UARegexMinimalString))\n| where HttpUserAgent has_any (UserAgentString) or HttpUserAgent matches regex UARegex\n| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by HttpUserAgent, SourceIP = SrcIpAddr, DstIpAddr, Account = SrcUsername, Url, Type\n)\n)\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "High",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "tags": [
          "log4j",
          "log4shell",
          "CVE2021-44228",
          {
            "Schema": "ASimWebSession"
          },
          {
            "SchemaVersion": "0.2.1"
          },
          {
            "Schema": "ASimNetworkSessions"
          },
          {
            "SchemaVersion": "0.2.1"
          }
        ],
        "techniques": [
          "T1190"
        ],
        "templateVersion": "1.0.9",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}