Ubiquiti - Large ICMP to external server

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Id	6df85d74-e32f-4b71-80e5-bfe2af00be1c
Rulename	Ubiquiti - Large ICMP to external server
Description	Detects large ICMP packets to external host.
Severity	Medium
Tactics	Exfiltration CommandAndControl
Techniques	T1041 T1572
Required data connectors	CustomLogsAma
Kind	Scheduled
Query frequency	1h
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Ubiquiti UniFi/Analytic Rules/UbiquitiL2RLargeIcmp.yaml
Version	1.0.2
Arm template	6df85d74-e32f-4b71-80e5-bfe2af00be1c.json

KQL

UbiquitiAuditEvent
| where EventCategory =~ 'firewall'
| where ipv4_is_private(SrcIpAddr)
| where ipv4_is_private(DstIpAddr) == 'False'
| where NetworkProtocol =~ 'ICMP'
| summarize avg_packet_length = avg(toint(NetworkBytes))
| extend a = 1
| join (UbiquitiAuditEvent
  | where EventCategory =~ 'firewall'
  | where ipv4_is_private(SrcIpAddr)
  | where ipv4_is_private(DstIpAddr) == 'False'
  | where NetworkProtocol =~ 'ICMP'
  | extend a = 1) on a
| where toint(NetworkBytes) > 2*avg_packet_length
| extend IPCustomEntity = SrcIpAddr

YAML

name: Ubiquiti - Large ICMP to external server
query: |
  UbiquitiAuditEvent
  | where EventCategory =~ 'firewall'
  | where ipv4_is_private(SrcIpAddr)
  | where ipv4_is_private(DstIpAddr) == 'False'
  | where NetworkProtocol =~ 'ICMP'
  | summarize avg_packet_length = avg(toint(NetworkBytes))
  | extend a = 1
  | join (UbiquitiAuditEvent
    | where EventCategory =~ 'firewall'
    | where ipv4_is_private(SrcIpAddr)
    | where ipv4_is_private(DstIpAddr) == 'False'
    | where NetworkProtocol =~ 'ICMP'
    | extend a = 1) on a
  | where toint(NetworkBytes) > 2*avg_packet_length
  | extend IPCustomEntity = SrcIpAddr  
entityMappings:
- entityType: IP
  fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
queryPeriod: 14d
version: 1.0.2
tactics:
- Exfiltration
- CommandAndControl
triggerOperator: gt
kind: Scheduled
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Ubiquiti UniFi/Analytic Rules/UbiquitiL2RLargeIcmp.yaml
relevantTechniques:
- T1041
- T1572
id: 6df85d74-e32f-4b71-80e5-bfe2af00be1c
severity: Medium
requiredDataConnectors:
- connectorId: CustomLogsAma
  dataTypes:
  - Ubiquiti_CL
status: Available
description: |
    'Detects large ICMP packets to external host.'
queryFrequency: 1h

ARM