detection.wiki

Detection rules › Kusto

NGINX - Private IP address in URL

Status
available
Severity
medium
Time window
1h
Source
github.com/Azure/Azure-Sentinel

'Detects requests to unusual URL'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1133 External Remote Services, T1190 Exploit Public-Facing Application

Rule body kusto

id: 1aa6bfed-f11b-402f-9007-0dccc1152ede
name: NGINX - Private IP address in URL
description: |
  'Detects requests to unusual URL'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: CustomLogsAma
    dataTypes:
      - NGINX_CL
queryFrequency: 1h
queryPeriod: 1h
triggerOperator: gt
triggerThreshold: 0
tactics:
  - InitialAccess
relevantTechniques:
  - T1190
  - T1133
query: |
  NGINXHTTPServer
  | where UrlOriginal matches regex @'(10\.\d{1,3}\.\d{1,3}\.\d{1,3})|(172\.1[6-9]\.\d{1,3}\.\d{1,3})|(172\.2[0-9]\.\d{1,3}\.\d{1,3})|(172\.3[0-1]\.\d{1,3}\.\d{1,3})|(192\.168\.\d{1,3}\.\d{1,3})'
  | extend UrlCustomEntity = UrlOriginal
entityMappings:
  - entityType: URL
    fieldMappings:
      - identifier: Url
        columnName: UrlCustomEntity
version: 1.0.2
kind: Scheduled

Stages and Predicates

Stage 1: source

NGINXHTTPServer

Stage 2: where

| where UrlOriginal matches regex @'(10\.\d{1,3}\.\d{1,3}\.\d{1,3})|(172\.1[6-9]\.\d{1,3}\.\d{1,3})|(172\.2[0-9]\.\d{1,3}\.\d{1,3})|(172\.3[0-1]\.\d{1,3}\.\d{1,3})|(192\.168\.\d{1,3}\.\d{1,3})'

Stage 3: extend

| extend UrlCustomEntity = UrlOriginal

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
UrlOriginalregex_match
    • (10.\d{1,3}.\d{1,3}.\d{1,3})
    • (172.1[6-9].\d{1,3}.\d{1,3})
    • (172.2[0-9].\d{1,3}.\d{1,3})
    • (172.3[0-1].\d{1,3}.\d{1,3})
    • (192.168.\d{1,3}.\d{1,3})

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
UrlCustomEntityextend