Cloudflare - XSS probing pattern in request

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Id	4d9d00b9-31a6-49e4-88c1-9e68277053ad
Rulename	Cloudflare - XSS probing pattern in request
Description	Detects XSS probing patterns.
Severity	Medium
Tactics	InitialAccess
Techniques	T1190 T1133
Required data connectors	CloudflareDataConnector
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/Cloudflare CCF/Analytic Rules/CloudflareCCFXSSProbingPattern.yaml
Version	1.0.1
Arm template	4d9d00b9-31a6-49e4-88c1-9e68277053ad.json

KQL

let s_threshold = 3;
Cloudflare
| where HttpRequestMethod in~ ('POST', 'PUT')
| extend susp_ch = countof(ClientRequestURI, '%00')
| where ClientRequestURI matches regex @'(alert\()|(alert\%28)|(String\.fromCharCode\()|(expression\(alert)' or susp_ch > s_threshold 
| extend CompleteUrl = strcat(HttpRequestHeaderHost,ClientRequestPath)

YAML

kind: Scheduled
severity: Medium
description: |
    'Detects XSS probing patterns.'
triggerThreshold: 0
status: Available
query: |
  let s_threshold = 3;
  Cloudflare
  | where HttpRequestMethod in~ ('POST', 'PUT')
  | extend susp_ch = countof(ClientRequestURI, '%00')
  | where ClientRequestURI matches regex @'(alert\()|(alert\%28)|(String\.fromCharCode\()|(expression\(alert)' or susp_ch > s_threshold 
  | extend CompleteUrl = strcat(HttpRequestHeaderHost,ClientRequestPath)  
relevantTechniques:
- T1190
- T1133
version: 1.0.1
triggerOperator: gt
entityMappings:
- fieldMappings:
  - identifier: Address
    columnName: SrcIpAddr
  entityType: IP
- fieldMappings:
  - identifier: Url
    columnName: CompleteUrl
  entityType: URL
requiredDataConnectors:
- connectorId: CloudflareDataConnector
  dataTypes:
  - Cloudflare
queryPeriod: 1h
tactics:
- InitialAccess
name: Cloudflare - XSS probing pattern in request
queryFrequency: 1h
id: 4d9d00b9-31a6-49e4-88c1-9e68277053ad
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare CCF/Analytic Rules/CloudflareCCFXSSProbingPattern.yaml

ARM