Azure DevOps Retention Reduced

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Id	71d374e0-1cf8-4e50-aecd-ab6c519795c2
Rulename	Azure DevOps Retention Reduced
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.
Severity	Low
Tactics	DefenseEvasion
Techniques	T1564
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADORetentionReduced.yaml
Version	1.0.5
Arm template	71d374e0-1cf8-4e50-aecd-ab6c519795c2.json

KQL

ADOAuditLogs
| 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])

YAML

tactics:
- DefenseEvasion
entityMappings:
- fieldMappings:
  - columnName: ActorUPN
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: IpAddress
    identifier: Address
  entityType: IP
queryPeriod: 1d
requiredDataConnectors: []
triggerThreshold: 0
status: Available
kind: Scheduled
relevantTechniques:
- T1564
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADORetentionReduced.yaml
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: |
  ADOAuditLogs
  | 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])  
version: 1.0.5
id: 71d374e0-1cf8-4e50-aecd-ab6c519795c2
name: Azure DevOps Retention Reduced
queryFrequency: 1d
triggerOperator: gt
severity: Low

ARM

{
  "$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": "ADOAuditLogs\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": "1.0.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}