Azure DevOps Retention Reduced

AzureDevOpsAuditing
| where OperationName =~ "Pipelines.PipelineRetentionSettingChanged"
| where Data.SettingName in ("PurgeArtifacts", "PurgeRuns")
| where Data.NewValue == 1 or Data.NewValue < Data.OldValue/2
| project-reorder TimeGenerated, OperationName, ActorUPN, IpAddress, UserAgent, Data
| extend timestamp = TimeGenerated
| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])

relevantTechniques:
- T1564
name: Azure DevOps Retention Reduced
requiredDataConnectors: []
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: ActorUPN
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: IpAddress
  entityType: IP
triggerThreshold: 0
id: 71d374e0-1cf8-4e50-aecd-ab6c519795c2
tactics:
- DefenseEvasion
version: 1.0.4
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADORetentionReduced.yaml
queryPeriod: 1d
kind: Scheduled
queryFrequency: 1d
severity: Low
status: Available
description: |
  'AzureDevOps retains items such as run records and produced artifacts for a configurable amount of time. An attacker looking to reduce the footprint left by their malicious activity may look to reduce the retention time for artifacts and runs.
  This query will look for where retention has been reduced to the minimum level - 1, or reduced by more than half.'  
query: |
  AzureDevOpsAuditing
  | where OperationName =~ "Pipelines.PipelineRetentionSettingChanged"
  | where Data.SettingName in ("PurgeArtifacts", "PurgeRuns")
  | where Data.NewValue == 1 or Data.NewValue < Data.OldValue/2
  | project-reorder TimeGenerated, OperationName, ActorUPN, IpAddress, UserAgent, Data
  | extend timestamp = TimeGenerated
  | extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])  
triggerOperator: gt

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/71d374e0-1cf8-4e50-aecd-ab6c519795c2')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/71d374e0-1cf8-4e50-aecd-ab6c519795c2')]",
      "properties": {
        "alertRuleTemplateName": "71d374e0-1cf8-4e50-aecd-ab6c519795c2",
        "customDetails": null,
        "description": "'AzureDevOps retains items such as run records and produced artifacts for a configurable amount of time. An attacker looking to reduce the footprint left by their malicious activity may look to reduce the retention time for artifacts and runs.\nThis query will look for where retention has been reduced to the minimum level - 1, or reduced by more than half.'\n",
        "displayName": "Azure DevOps Retention Reduced",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "ActorUPN",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountUPNSuffix",
                "identifier": "UPNSuffix"
              }
            ]
          },
          {
            "entityType": "IP",
            "fieldMappings": [
              {
                "columnName": "IpAddress",
                "identifier": "Address"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADORetentionReduced.yaml",
        "query": "AzureDevOpsAuditing\n| where OperationName =~ \"Pipelines.PipelineRetentionSettingChanged\"\n| where Data.SettingName in (\"PurgeArtifacts\", \"PurgeRuns\")\n| where Data.NewValue == 1 or Data.NewValue < Data.OldValue/2\n| project-reorder TimeGenerated, OperationName, ActorUPN, IpAddress, UserAgent, Data\n| extend timestamp = TimeGenerated\n| extend AccountName = tostring(split(ActorUPN, \"@\")[0]), AccountUPNSuffix = tostring(split(ActorUPN, \"@\")[1])\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Low",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1564"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}