Detection rules › Kusto
PaloAlto - Inbound connection to high risk ports
'Detects inbound connection to high risk ports.'
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access |
Rule body
id: b2dd2dac-51c9-11ec-bf63-0242ac130002
name: PaloAlto - Inbound connection to high risk ports
description: |
'Detects inbound connection to high risk ports.'
severity: Medium
status: Available
requiredDataConnectors:
- connectorId: CefAma
dataTypes:
- CommonSecurityLog
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
relevantTechniques:
- T1190
- T1133
query: |
let HighRiskPorts = dynamic(['21', '22', '23', '25', '53', '443', '110', '135', '137', '138', '139', '1433', '1434']);
PaloAltoCDLEvent
| where EventResourceId =~ 'TRAFFIC'
| where ipv4_is_private(SrcIpAddr) == false
| where DstPortNumber in (HighRiskPorts)
| extend IPCustomEntity = SrcIpAddr
entityMappings:
- entityType: IP
fieldMappings:
- identifier: Address
columnName: IPCustomEntity
version: 1.0.3
kind: Scheduled
Stages and Predicates
Parameters
let HighRiskPorts = dynamic(['21', '22', '23', '25', '53', '443', '110', '135', '137', '138', '139', '1433', '1434']);
Stage 1: source
PaloAltoCDLEvent
Stage 2: where
| where EventResourceId =~ 'TRAFFIC'
Stage 3: where
| where ipv4_is_private(SrcIpAddr) == false
Stage 4: where
| where DstPortNumber in (HighRiskPorts)
Stage 5: extend
| extend IPCustomEntity = SrcIpAddr
Exclusions
The rule actively suppresses these predicates.
| Field | Kind | Excluded values | Search |
|---|---|---|---|
SrcIpAddr | cidr_match | 10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 169.254.0.0/16, 127.0.0.0/8 | excludes:SrcIpAddr |
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
DstPortNumber | in |
| field:"DstPortNumber" kind:in |
EventResourceId | eq |
| field:"EventResourceId" kind:eq value:"TRAFFIC" |
Output fields
These fields are emitted when the rule matches.
| Field | Source |
|---|---|
IPCustomEntity | extend |