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])

triggerOperator: gt
queryFrequency: 1d
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.'  
status: Available
kind: Scheduled
triggerThreshold: 0
requiredDataConnectors: []
version: 1.0.4
queryPeriod: 1d
name: Azure DevOps Retention Reduced
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADORetentionReduced.yaml
id: 71d374e0-1cf8-4e50-aecd-ab6c519795c2
tactics:
- DefenseEvasion
relevantTechniques:
- T1564
severity: Low
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: ActorUPN
  - identifier: Name
    columnName: AccountName
  - identifier: UPNSuffix
    columnName: AccountUPNSuffix
  entityType: Account
- fieldMappings:
  - identifier: Address
    columnName: IpAddress
  entityType: IP
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])  

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-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",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1564"
        ],
        "templateVersion": "1.0.4",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}