NGINX - Multiple user agents for single source

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Id	83a0b48f-1cb7-4b4f-a018-23c3203a239b
Rulename	NGINX - Multiple user agents for single source
Description	Detects requests with different user agents from one source in short timeframe.
Severity	Medium
Tactics	InitialAccess
Techniques	T1190 T1133
Required data connectors	CustomLogsAma
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/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
Version	1.0.2
Arm template	83a0b48f-1cb7-4b4f-a018-23c3203a239b.json

KQL

let threshold = 5;
NGINXHTTPServer
| summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
| extend ua_count = array_length(set_HttpUserAgentOriginal)
| where ua_count > threshold
| extend IPCustomEntity = SrcIpAddr

YAML

description: |
    'Detects requests with different user agents from one source in short timeframe.'
version: 1.0.2
triggerThreshold: 0
tactics:
- InitialAccess
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/NGINX HTTP Server/Analytic Rules/NGINXDifferentUAsFromSingleIP.yaml
triggerOperator: gt
status: Available
id: 83a0b48f-1cb7-4b4f-a018-23c3203a239b
name: NGINX - Multiple user agents for single source
queryFrequency: 1h
severity: Medium
kind: Scheduled
entityMappings:
- fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
  entityType: IP
relevantTechniques:
- T1190
- T1133
query: |
  let threshold = 5;
  NGINXHTTPServer
  | summarize makeset(HttpUserAgentOriginal) by SrcIpAddr, bin(TimeGenerated, 5m)
  | extend ua_count = array_length(set_HttpUserAgentOriginal)
  | where ua_count > threshold
  | extend IPCustomEntity = SrcIpAddr  
requiredDataConnectors:
- dataTypes:
  - NGINX_CL
  connectorId: CustomLogsAma

ARM