User agent search for log4j exploitation attempt

let UserAgentString = dynamic (["${jndi:ldap:/", "${jndi:rmi:/", "${jndi:ldaps:/", "${jndi:dns:/", "${jndi:iiop:/","${jndi:","${jndi:nds:/","${jndi:corba/"]);
let UARegexMinimalString=dynamic(['{','%7b', '%7B']);
let UARegex = @'(\\$|%24)(\\{|%7B)([^jJ]*[jJ])([^nN]*[nN])([^dD]*[dD])([^iI]*[iI])(:|%3A|\\$|%24|}|%7D)';
(union isfuzzy=true
(OfficeActivity
| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = ClientIP, Account = UserId, Type, Operation
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
),
(AzureDiagnostics
| where Category in ("FrontdoorWebApplicationFirewallLog", "FrontdoorAccessLog", "ApplicationGatewayFirewallLog", "ApplicationGatewayAccessLog")
| where userAgent_s has_any (UserAgentString) or userAgent_s matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = userAgent_s, SourceIP = clientIP_s, Type, host_s, requestUri_s, httpStatus_d
| extend timestamp = StartTime, IPCustomEntity = SourceIP, UrlCustomEntity = requestUri_s
),
(
W3CIISLog
| where csUserAgent has_any (UserAgentString) or csUserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = csUserAgent, SourceIP = cIP, Account = csUserName, Type, sSiteName, csMethod, csUriStem
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = csUriStem
),
(
AWSCloudTrail
| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = SourceIpAddress, Account = UserIdentityUserName, Type, EventName
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
),
(SigninLogs
| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail),    AppDisplayName, ClientAppUsed
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
),
(AADNonInteractiveUserSignInLogs 
| where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail), AppDisplayName, ClientAppUsed
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
),
(_Im_WebSession (httpuseragent_has_any=array_concat(UserAgentString,UARegexMinimalString))
| where HttpUserAgent has_any (UserAgentString) or HttpUserAgent matches regex UARegex
| summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by HttpUserAgent, SourceIP = SrcIpAddr, DstIpAddr, Account = SrcUsername, Url, Type
| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = Url
)
)

name: User agent search for log4j exploitation attempt
query: |
  let UserAgentString = dynamic (["${jndi:ldap:/", "${jndi:rmi:/", "${jndi:ldaps:/", "${jndi:dns:/", "${jndi:iiop:/","${jndi:","${jndi:nds:/","${jndi:corba/"]);
  let UARegexMinimalString=dynamic(['{','%7b', '%7B']);
  let UARegex = @'(\\$|%24)(\\{|%7B)([^jJ]*[jJ])([^nN]*[nN])([^dD]*[dD])([^iI]*[iI])(:|%3A|\\$|%24|}|%7D)';
  (union isfuzzy=true
  (OfficeActivity
  | where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = ClientIP, Account = UserId, Type, Operation
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
  ),
  (AzureDiagnostics
  | where Category in ("FrontdoorWebApplicationFirewallLog", "FrontdoorAccessLog", "ApplicationGatewayFirewallLog", "ApplicationGatewayAccessLog")
  | where userAgent_s has_any (UserAgentString) or userAgent_s matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = userAgent_s, SourceIP = clientIP_s, Type, host_s, requestUri_s, httpStatus_d
  | extend timestamp = StartTime, IPCustomEntity = SourceIP, UrlCustomEntity = requestUri_s
  ),
  (
  W3CIISLog
  | where csUserAgent has_any (UserAgentString) or csUserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent = csUserAgent, SourceIP = cIP, Account = csUserName, Type, sSiteName, csMethod, csUriStem
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = csUriStem
  ),
  (
  AWSCloudTrail
  | where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = SourceIpAddress, Account = UserIdentityUserName, Type, EventName
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
  ),
  (SigninLogs
  | where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail),    AppDisplayName, ClientAppUsed
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
  ),
  (AADNonInteractiveUserSignInLogs 
  | where UserAgent has_any (UserAgentString) or UserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by UserAgent, SourceIP = IPAddress, Account = UserPrincipalName, Type, Operation = OperationName, tostring(LocationDetails), tostring(DeviceDetail), AppDisplayName, ClientAppUsed
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP
  ),
  (_Im_WebSession (httpuseragent_has_any=array_concat(UserAgentString,UARegexMinimalString))
  | where HttpUserAgent has_any (UserAgentString) or HttpUserAgent matches regex UARegex
  | summarize StartTime = min(TimeGenerated), EndTime = max(TimeGenerated) by HttpUserAgent, SourceIP = SrcIpAddr, DstIpAddr, Account = SrcUsername, Url, Type
  | extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = Url
  )
  )  
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Apache Log4j Vulnerability Detection/Analytic Rules/UserAgentSearch_log4j.yaml
queryFrequency: 1d
triggerThreshold: 0
requiredDataConnectors:
- dataTypes:
  - SquidProxy_CL
  connectorId: SquidProxy
- dataTypes:
  - CommonSecurityLog
  connectorId: Zscaler
- dataTypes:
  - AzureDiagnostics
  connectorId: WAF
- dataTypes:
  - OfficeActivity
  connectorId: Office365
- dataTypes:
  - SigninLogs
  connectorId: AzureActiveDirectory
- dataTypes:
  - AADNonInteractiveUserSignInLogs
  connectorId: AzureActiveDirectory
- dataTypes:
  - AWSCloudTrail
  connectorId: AWS
- dataTypes:
  - W3CIISLog
  connectorId: AzureMonitor(IIS)
version: 1.0.2
status: Available
queryPeriod: 1d
id: 29283b22-a1c0-4d16-b0a9-3460b655a46a
triggerOperator: gt
entityMappings:
- fieldMappings:
  - identifier: Url
    columnName: UrlCustomEntity
  entityType: URL
- fieldMappings:
  - identifier: Address
    columnName: IPCustomEntity
  entityType: IP
- fieldMappings:
  - identifier: Name
    columnName: AccountCustomEntity
  entityType: Account
tags:
- log4j
- log4shell
- CVE2021-44228
- Schema: ASimWebSession
- SchemaVersion: 0.2.1
- Schema: ASimNetworkSessions
- SchemaVersion: 0.2.1
relevantTechniques:
- T1190
severity: High
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. Log4j 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.
   Reference: https://msrc-blog.microsoft.com/2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/'  
kind: Scheduled
tactics:
- InitialAccess

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/29283b22-a1c0-4d16-b0a9-3460b655a46a')]",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/29283b22-a1c0-4d16-b0a9-3460b655a46a')]",
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
      "kind": "Scheduled",
      "apiVersion": "2022-11-01",
      "properties": {
        "displayName": "User agent search for log4j exploitation attempt",
        "description": "'This query uses various log sources having user agent data to look for log4j CVE-2021-44228 exploitation attempt based on user agent pattern. Log4j is an open-source Apache logging library that is used in \n many Java-based applications. The regex and the string matching look for the most common attacks. This might not be comprehensive to detect every possible user agent variation.\n Reference: https://msrc-blog.microsoft.com/2021/12/11/microsofts-response-to-cve-2021-44228-apache-log4j2/'\n",
        "severity": "High",
        "enabled": true,
        "query": "let UserAgentString = dynamic ([\"${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| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP\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 = clientIP_s, Type, host_s, requestUri_s, httpStatus_d\n| extend timestamp = StartTime, IPCustomEntity = SourceIP, UrlCustomEntity = requestUri_s\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, csUriStem\n| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = 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| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP\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| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP\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| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP\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| extend timestamp = StartTime, AccountCustomEntity = Account, IPCustomEntity = SourceIP, UrlCustomEntity = Url\n)\n)\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0,
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "InitialAccess"
        ],
        "techniques": [
          "T1190"
        ],
        "alertRuleTemplateName": "29283b22-a1c0-4d16-b0a9-3460b655a46a",
        "customDetails": null,
        "entityMappings": [
          {
            "fieldMappings": [
              {
                "identifier": "Url",
                "columnName": "UrlCustomEntity"
              }
            ],
            "entityType": "URL"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Address",
                "columnName": "IPCustomEntity"
              }
            ],
            "entityType": "IP"
          },
          {
            "fieldMappings": [
              {
                "identifier": "Name",
                "columnName": "AccountCustomEntity"
              }
            ],
            "entityType": "Account"
          }
        ],
        "tags": [
          "log4j",
          "log4shell",
          "CVE2021-44228",
          {
            "Schema": "ASimWebSession"
          },
          {
            "SchemaVersion": "0.2.1"
          },
          {
            "Schema": "ASimNetworkSessions"
          },
          {
            "SchemaVersion": "0.2.1"
          }
        ],
        "status": "Available",
        "templateVersion": "1.0.2",
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Apache Log4j Vulnerability Detection/Analytic Rules/UserAgentSearch_log4j.yaml"
      }
    }
  ]
}