Cloudflare - XSS probing pattern in request

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Id	4d9d00b9-31a6-49e4-88c1-9e68277053ac
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/Analytic Rules/CloudflareXSSProbingPattern.yaml
Version	1.0.0
Arm template	4d9d00b9-31a6-49e4-88c1-9e68277053ac.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 IPCustomEntity = SrcIpAddr
| extend UrlCustomEntity = ClientRequestURI

YAML

queryPeriod: 1h
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 IPCustomEntity = SrcIpAddr
  | extend UrlCustomEntity = ClientRequestURI  
name: Cloudflare - XSS probing pattern in request
entityMappings:
- fieldMappings:
  - columnName: IPCustomEntity
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: UrlCustomEntity
    identifier: Url
  entityType: URL
queryFrequency: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare/Analytic Rules/CloudflareXSSProbingPattern.yaml
requiredDataConnectors:
- connectorId: CloudflareDataConnector
  dataTypes:
  - Cloudflare
description: |
    'Detects XSS probing patterns.'
kind: Scheduled
version: 1.0.0
status: Available
severity: Medium
relevantTechniques:
- T1190
- T1133
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
id: 4d9d00b9-31a6-49e4-88c1-9e68277053ac

ARM