Azure DevOps Pull Request Policy Bypassing - Historic allow list

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Id	4d8de9e6-263e-4845-8618-cd23a4f58b70
Rulename	Azure DevOps Pull Request Policy Bypassing - Historic allow list
Description	This detection builds an allow list of historic PR policy bypasses and compares to recent history, flagging pull request bypasses that are not manually in the allow list and not historically included in the allow list.
Severity	Medium
Tactics	Persistence
Techniques	T1098
Kind	Scheduled
Query frequency	3h
Query period	14d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/AzDOHistoricPrPolicyBypassing.yaml
Version	1.0.5
Arm template	4d8de9e6-263e-4845-8618-cd23a4f58b70.json

KQL

let starttime = 14d;
let endtime = 3h;
// Add full UPN (user@domain.com) to Authorized Bypassers to ignore policy bypasses by certain authorized users
let AuthorizedBypassers = dynamic(['foo@baz.com', 'test@foo.com']);
let historicBypassers = AzureDevOpsAuditing
| where TimeGenerated between (ago(starttime) .. ago(endtime))
| where OperationName == 'Git.RefUpdatePoliciesBypassed'
| distinct ActorUPN;
AzureDevOpsAuditing
| where TimeGenerated >= ago(endtime)
| where OperationName == 'Git.RefUpdatePoliciesBypassed'
| where ActorUPN !in (historicBypassers) and ActorUPN !in (AuthorizedBypassers)
| parse ScopeDisplayName with OrganizationName '(Organization)'
| project TimeGenerated, ActorUPN, IpAddress, UserAgent, OrganizationName, ProjectName, RepoName = Data.RepoName, AlertDetails = Details, Branch = Data.Name,
  BypassReason = Data.BypassReason, PRLink = strcat('https://dev.azure.com/', OrganizationName, '/', ProjectName, '/_git/', Data.RepoName, '/pullrequest/', Data.PullRequestId)
| extend timestamp = TimeGenerated
| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])

YAML

status: Available
requiredDataConnectors: []
id: 4d8de9e6-263e-4845-8618-cd23a4f58b70
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/AzDOHistoricPrPolicyBypassing.yaml
triggerThreshold: 0
query: |
  let starttime = 14d;
  let endtime = 3h;
  // Add full UPN (user@domain.com) to Authorized Bypassers to ignore policy bypasses by certain authorized users
  let AuthorizedBypassers = dynamic(['foo@baz.com', 'test@foo.com']);
  let historicBypassers = AzureDevOpsAuditing
  | where TimeGenerated between (ago(starttime) .. ago(endtime))
  | where OperationName == 'Git.RefUpdatePoliciesBypassed'
  | distinct ActorUPN;
  AzureDevOpsAuditing
  | where TimeGenerated >= ago(endtime)
  | where OperationName == 'Git.RefUpdatePoliciesBypassed'
  | where ActorUPN !in (historicBypassers) and ActorUPN !in (AuthorizedBypassers)
  | parse ScopeDisplayName with OrganizationName '(Organization)'
  | project TimeGenerated, ActorUPN, IpAddress, UserAgent, OrganizationName, ProjectName, RepoName = Data.RepoName, AlertDetails = Details, Branch = Data.Name,
    BypassReason = Data.BypassReason, PRLink = strcat('https://dev.azure.com/', OrganizationName, '/', ProjectName, '/_git/', Data.RepoName, '/pullrequest/', Data.PullRequestId)
  | extend timestamp = TimeGenerated
  | extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])  
severity: Medium
entityMappings:
- fieldMappings:
  - columnName: ActorUPN
    identifier: FullName
  - columnName: AccountName
    identifier: Name
  - columnName: AccountUPNSuffix
    identifier: UPNSuffix
  entityType: Account
- fieldMappings:
  - columnName: IpAddress
    identifier: Address
  entityType: IP
- fieldMappings:
  - columnName: PRLink
    identifier: Url
  entityType: URL
tactics:
- Persistence
version: 1.0.5
kind: Scheduled
relevantTechniques:
- T1098
name: Azure DevOps Pull Request Policy Bypassing - Historic allow list
triggerOperator: gt
queryFrequency: 3h
description: |
    'This detection builds an allow list of historic PR policy bypasses and compares to recent history, flagging pull request bypasses that are not manually in the allow list and not historically included in the allow list.'
queryPeriod: 14d

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/4d8de9e6-263e-4845-8618-cd23a4f58b70')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/4d8de9e6-263e-4845-8618-cd23a4f58b70')]",
      "properties": {
        "alertRuleTemplateName": "4d8de9e6-263e-4845-8618-cd23a4f58b70",
        "customDetails": null,
        "description": "'This detection builds an allow list of historic PR policy bypasses and compares to recent history, flagging pull request bypasses that are not manually in the allow list and not historically included in the allow list.'\n",
        "displayName": "Azure DevOps Pull Request Policy Bypassing - Historic allow list",
        "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"
              }
            ]
          },
          {
            "entityType": "URL",
            "fieldMappings": [
              {
                "columnName": "PRLink",
                "identifier": "Url"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/AzDOHistoricPrPolicyBypassing.yaml",
        "query": "let starttime = 14d;\nlet endtime = 3h;\n// Add full UPN (user@domain.com) to Authorized Bypassers to ignore policy bypasses by certain authorized users\nlet AuthorizedBypassers = dynamic(['foo@baz.com', 'test@foo.com']);\nlet historicBypassers = AzureDevOpsAuditing\n| where TimeGenerated between (ago(starttime) .. ago(endtime))\n| where OperationName == 'Git.RefUpdatePoliciesBypassed'\n| distinct ActorUPN;\nAzureDevOpsAuditing\n| where TimeGenerated >= ago(endtime)\n| where OperationName == 'Git.RefUpdatePoliciesBypassed'\n| where ActorUPN !in (historicBypassers) and ActorUPN !in (AuthorizedBypassers)\n| parse ScopeDisplayName with OrganizationName '(Organization)'\n| project TimeGenerated, ActorUPN, IpAddress, UserAgent, OrganizationName, ProjectName, RepoName = Data.RepoName, AlertDetails = Details, Branch = Data.Name,\n  BypassReason = Data.BypassReason, PRLink = strcat('https://dev.azure.com/', OrganizationName, '/', ProjectName, '/_git/', Data.RepoName, '/pullrequest/', Data.PullRequestId)\n| extend timestamp = TimeGenerated\n| extend AccountName = tostring(split(ActorUPN, \"@\")[0]), AccountUPNSuffix = tostring(split(ActorUPN, \"@\")[1])\n",
        "queryFrequency": "PT3H",
        "queryPeriod": "P14D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "Persistence"
        ],
        "techniques": [
          "T1098"
        ],
        "templateVersion": "1.0.5",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}