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

OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Cloudflare CCF/Analytic Rules/CloudflareCCFXSSProbingPattern.yaml
queryFrequency: 1h
name: Cloudflare - XSS probing pattern in request
severity: Medium
triggerThreshold: 0
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)  
requiredDataConnectors:
- dataTypes:
  - Cloudflare
  connectorId: CloudflareDataConnector
relevantTechniques:
- T1190
- T1133
status: Available
triggerOperator: gt
queryPeriod: 1h
description: |
    'Detects XSS probing patterns.'
id: 4d9d00b9-31a6-49e4-88c1-9e68277053ad
version: 1.0.1
entityMappings:
- fieldMappings:
  - columnName: SrcIpAddr
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: CompleteUrl
    identifier: Url
  entityType: URL
kind: Scheduled
tactics:
- InitialAccess

ARM