VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure

Syslog
| where SyslogMessage contains "VCF Drop"
| where SyslogMessage contains "Reverse path forwarding check fail"
| project-rename EdgeName=HostName
| project-away Computer, HostIP, SourceSystem, Type
| extend OverlaySegmentName = extract("SEGMENT_NAME=(.+) COUNT=", 1, SyslogMessage)
| extend IpProtocol = extract("PROTO=(.+) SRC=", 1, SyslogMessage)
| extend SrcIpAddress = extract("SRC=(.+) DST=", 1, SyslogMessage)
| extend DstIpAddress = extract("DST=(.+) REASON=", 1, SyslogMessage)
| extend EdgeFwAction = extract("ACTION=(.+) SEGMENT=", 1, SyslogMessage)
| extend SyslogTag = extract("^(.+): ACTION=", 1, SyslogMessage)
| extend pcktCount = extract("COUNT=([0-9]+)$", 1, SyslogMessage)
| project
    TimeGenerated,
    EdgeFwAction,
    EdgeName,
    SrcIpAddress,
    IpProtocol,
    DstIpAddress,
    pcktCount,
    SyslogTag

queryFrequency: 1h
entityMappings:
- fieldMappings:
  - columnName: SrcIpAddress
    identifier: Address
  entityType: IP
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    groupByEntities: []
    reopenClosedIncident: false
    matchingMethod: AllEntities
    lookbackDuration: 1h
    groupByAlertDetails: []
    enabled: true
    groupByCustomDetails: []
triggerThreshold: 0
suppressionEnabled: false
triggerOperator: gt
severity: Low
suppressionDuration: 5h
eventGroupingSettings:
  aggregationKind: SingleAlert
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMware%20SD-WAN%20and%20SASE/Analytic%20Rules/vmw-sdwan-rpfcheck.yaml
query: |+
  Syslog
  | where SyslogMessage contains "VCF Drop"
  | where SyslogMessage contains "Reverse path forwarding check fail"
  | project-rename EdgeName=HostName
  | project-away Computer, HostIP, SourceSystem, Type
  | extend OverlaySegmentName = extract("SEGMENT_NAME=(.+) COUNT=", 1, SyslogMessage)
  | extend IpProtocol = extract("PROTO=(.+) SRC=", 1, SyslogMessage)
  | extend SrcIpAddress = extract("SRC=(.+) DST=", 1, SyslogMessage)
  | extend DstIpAddress = extract("DST=(.+) REASON=", 1, SyslogMessage)
  | extend EdgeFwAction = extract("ACTION=(.+) SEGMENT=", 1, SyslogMessage)
  | extend SyslogTag = extract("^(.+): ACTION=", 1, SyslogMessage)
  | extend pcktCount = extract("COUNT=([0-9]+)$", 1, SyslogMessage)
  | project
      TimeGenerated,
      EdgeFwAction,
      EdgeName,
      SrcIpAddress,
      IpProtocol,
      DstIpAddress,
      pcktCount,
      SyslogTag

tactics:
- Impact
queryPeriod: 1h
customDetails:
  Edge_Name: EdgeName
relevantTechniques:
- T1498
requiredDataConnectors:
- connectorId: VMwareSDWAN
  dataTypes:
  - SDWAN
id: 840b050f-842b-4264-8973-d4f9b65facb5
version: 1.0.0
description: |-
  The VMware SD-WAN Edge appliance received packets that failed a Reverse Path Forwarding (RPF) Check.

  Reverse path forwarding (RPF) check is a network security mechanism that verifies whether the source IP address of a packet is reachable through the incoming interface on which the packet is received. The packet is dropped if the source IP address is not reachable through the incoming interface.

  RPF checks prevent spoofing attacks, in which an attacker uses a forged source IP address to make it appear that the packets are coming from a trusted source. This can allow the attacker to gain unauthorized network access or launch a denial-of-service attack against a target system.

  An IP fragmentation attack is a cyberattack that exploits how IP packets are fragmented and reassembled. IP fragmentation is a process by which large IP packets are broken down into smaller packets to transmit them over networks with smaller Maximum Transmission Unit (MTU) sizes.

  This analytics rule analyzes Syslog streams; these alerts are not reported by default if Search API is used.
kind: Scheduled
name: VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure

{
  "$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/840b050f-842b-4264-8973-d4f9b65facb5')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/840b050f-842b-4264-8973-d4f9b65facb5')]",
      "properties": {
        "alertRuleTemplateName": "840b050f-842b-4264-8973-d4f9b65facb5",
        "customDetails": {
          "Edge_Name": "EdgeName"
        },
        "description": "The VMware SD-WAN Edge appliance received packets that failed a Reverse Path Forwarding (RPF) Check.\n\nReverse path forwarding (RPF) check is a network security mechanism that verifies whether the source IP address of a packet is reachable through the incoming interface on which the packet is received. The packet is dropped if the source IP address is not reachable through the incoming interface.\n\nRPF checks prevent spoofing attacks, in which an attacker uses a forged source IP address to make it appear that the packets are coming from a trusted source. This can allow the attacker to gain unauthorized network access or launch a denial-of-service attack against a target system.\n\nAn IP fragmentation attack is a cyberattack that exploits how IP packets are fragmented and reassembled. IP fragmentation is a process by which large IP packets are broken down into smaller packets to transmit them over networks with smaller Maximum Transmission Unit (MTU) sizes.\n\nThis analytics rule analyzes Syslog streams; these alerts are not reported by default if Search API is used.",
        "displayName": "VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "SrcIpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "eventGroupingSettings": {
          "aggregationKind": "SingleAlert"
        },
        "incidentConfiguration": {
          "createIncident": true,
          "groupingConfiguration": {
            "enabled": true,
            "groupByAlertDetails": [],
            "groupByCustomDetails": [],
            "groupByEntities": [],
            "lookbackDuration": "PT1H",
            "matchingMethod": "AllEntities",
            "reopenClosedIncident": false
          }
        },
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMware%20SD-WAN%20and%20SASE/Analytic%20Rules/vmw-sdwan-rpfcheck.yaml",
        "query": "Syslog\n| where SyslogMessage contains \"VCF Drop\"\n| where SyslogMessage contains \"Reverse path forwarding check fail\"\n| project-rename EdgeName=HostName\n| project-away Computer, HostIP, SourceSystem, Type\n| extend OverlaySegmentName = extract(\"SEGMENT_NAME=(.+) COUNT=\", 1, SyslogMessage)\n| extend IpProtocol = extract(\"PROTO=(.+) SRC=\", 1, SyslogMessage)\n| extend SrcIpAddress = extract(\"SRC=(.+) DST=\", 1, SyslogMessage)\n| extend DstIpAddress = extract(\"DST=(.+) REASON=\", 1, SyslogMessage)\n| extend EdgeFwAction = extract(\"ACTION=(.+) SEGMENT=\", 1, SyslogMessage)\n| extend SyslogTag = extract(\"^(.+): ACTION=\", 1, SyslogMessage)\n| extend pcktCount = extract(\"COUNT=([0-9]+)$\", 1, SyslogMessage)\n| project\n    TimeGenerated,\n    EdgeFwAction,\n    EdgeName,\n    SrcIpAddress,\n    IpProtocol,\n    DstIpAddress,\n    pcktCount,\n    SyslogTag\n\n",
        "queryFrequency": "PT1H",
        "queryPeriod": "PT1H",
        "severity": "Low",
        "subTechniques": [],
        "suppressionDuration": "PT5H",
        "suppressionEnabled": false,
        "tactics": [
          "Impact"
        ],
        "techniques": [
          "T1498"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}