VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure
Id | 840b050f-842b-4264-8973-d4f9b65facb5 |
Rulename | VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure |
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. |
Severity | Low |
Tactics | Impact |
Techniques | T1498 |
Required data connectors | VMwareSDWAN |
Kind | Scheduled |
Query frequency | 1h |
Query period | 1h |
Trigger threshold | 0 |
Trigger operator | gt |
Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMware SD-WAN and SASE/Analytic Rules/vmw-sdwan-rpfcheck.yaml |
Version | 1.0.0 |
Arm template | 840b050f-842b-4264-8973-d4f9b65facb5.json |
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
severity: Low
relevantTechniques:
- T1498
queryFrequency: 1h
kind: Scheduled
version: 1.0.0
triggerOperator: gt
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.
incidentConfiguration:
createIncident: true
groupingConfiguration:
lookbackDuration: 1h
groupByEntities: []
reopenClosedIncident: false
enabled: true
matchingMethod: AllEntities
groupByAlertDetails: []
groupByCustomDetails: []
entityMappings:
- entityType: IP
fieldMappings:
- columnName: SrcIpAddress
identifier: Address
queryPeriod: 1h
suppressionEnabled: false
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
suppressionDuration: 5h
customDetails:
Edge_Name: EdgeName
tactics:
- Impact
name: VMware SD-WAN Edge - Network Anomaly Detection - RPF Check Failure
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMware SD-WAN and SASE/Analytic Rules/vmw-sdwan-rpfcheck.yaml
eventGroupingSettings:
aggregationKind: SingleAlert
id: 840b050f-842b-4264-8973-d4f9b65facb5
requiredDataConnectors:
- dataTypes:
- SDWAN
connectorId: VMwareSDWAN
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"apiVersion": "2023-02-01-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 SD-WAN and SASE/Analytic Rules/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",
"suppressionDuration": "PT5H",
"suppressionEnabled": false,
"tactics": [
"Impact"
],
"techniques": [
"T1498"
],
"templateVersion": "1.0.0",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}