VMware SD-WAN Edge - Network Anomaly Detection - Potential Fragmentation Attack

Back


Id	ce207901-ed7b-49ae-ada7-033e1fbb1240
Rulename	VMware SD-WAN Edge - Network Anomaly Detection - Potential Fragmentation Attack
Description	The VMware SD-WAN Edge appliance received packets potentially part of an IP Fragmentation attack or indicating an MTU mismatch. 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. Attackers can exploit IP fragmentation in various ways, for example, Denial-of-service attacks, address spoofing, or even information disclosure. This analytics rule analyzes Syslog streams; these alerts are not reported by default if Search API is used.
Severity	Low
Tactics	Impact DefenseEvasion
Techniques	T1498 T1599
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-ipfrag-attempt.yaml
Version	1.0.0
Arm template	ce207901-ed7b-49ae-ada7-033e1fbb1240.json

KQL

Syslog
| where SyslogMessage contains "VCF Drop"
| where SyslogMessage contains "packet too big"
| 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

YAML

queryFrequency: 1h
kind: Scheduled
description: |-
  The VMware SD-WAN Edge appliance received packets potentially part of an IP Fragmentation attack or indicating an MTU mismatch.

  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.

  Attackers can exploit IP fragmentation in various ways, for example, Denial-of-service attacks, address spoofing, or even information disclosure.

  This analytics rule analyzes Syslog streams; these alerts are not reported by default if Search API is used.  
triggerThreshold: 0
tactics:
- Impact
- DefenseEvasion
customDetails:
  Edge_Name: EdgeName
relevantTechniques:
- T1498
- T1599
requiredDataConnectors:
- connectorId: VMwareSDWAN
  dataTypes:
  - SDWAN
query: |+
  Syslog
  | where SyslogMessage contains "VCF Drop"
  | where SyslogMessage contains "packet too big"
  | 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
entityMappings:
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SrcIpAddress
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/VMware SD-WAN and SASE/Analytic Rules/vmw-sdwan-ipfrag-attempt.yaml
eventGroupingSettings:
  aggregationKind: SingleAlert
queryPeriod: 1h
id: ce207901-ed7b-49ae-ada7-033e1fbb1240
suppressionEnabled: false
name: VMware SD-WAN Edge - Network Anomaly Detection - Potential Fragmentation Attack
suppressionDuration: 5h
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    groupByAlertDetails: []
    groupByCustomDetails: []
    groupByEntities: []
    reopenClosedIncident: false
    lookbackDuration: 1h
    enabled: true
    matchingMethod: AllEntities
version: 1.0.0
triggerOperator: gt

ARM