Azure DevOps Build Variable Modified by New User
Id | 3b9a44d7-c651-45ed-816c-eae583a6f2f1 |
Rulename | Azure DevOps Build Variable Modified by New User |
Description | Variables can be configured and used at any stage of the build process in Azure DevOps to inject values. An attacker with the required permissions could modify or add to these variables to conduct malicious activity such as changing paths or remote endpoints called during the build. As variables are often changed by users, just detecting these changes would have a high false positive rate. This detection looks for modifications to variable groups where that user has not been observed modifying them before. |
Severity | Medium |
Tactics | DefenseEvasion |
Techniques | T1578 |
Kind | Scheduled |
Query frequency | 1d |
Query period | 14d |
Trigger threshold | 0 |
Trigger operator | gt |
Source Uri | https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADOVariableModifiedByNewUser.yaml |
Version | 1.0.6 |
Arm template | 3b9a44d7-c651-45ed-816c-eae583a6f2f1.json |
let lookback = 14d;
let timeframe = 1d;
let historical_data =
ADOAuditLogs
| where TimeGenerated > ago(lookback) and TimeGenerated < ago(timeframe)
| where OperationName =~ "Library.VariableGroupModified"
| extend variables = Data.Variables
| extend VariableGroupId = tostring(Data.VariableGroupId)
| extend UserKey = strcat(VariableGroupId, "-", ActorUserId)
| project UserKey;
ADOAuditLogs
| where TimeGenerated > ago(timeframe)
| where OperationName =~ "Library.VariableGroupModified"
| extend VariableGroupName = tostring(Data.VariableGroupName)
| extend VariableGroupId = tostring(Data.VariableGroupId)
| extend UserKey = strcat(VariableGroupId, "-", ActorUserId)
| where UserKey !in (historical_data)
| project-away UserKey
| project-reorder TimeGenerated, VariableGroupName, ActorUPN, IpAddress, UserAgent
| extend timestamp = TimeGenerated
| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADOVariableModifiedByNewUser.yaml
query: |
let lookback = 14d;
let timeframe = 1d;
let historical_data =
ADOAuditLogs
| where TimeGenerated > ago(lookback) and TimeGenerated < ago(timeframe)
| where OperationName =~ "Library.VariableGroupModified"
| extend variables = Data.Variables
| extend VariableGroupId = tostring(Data.VariableGroupId)
| extend UserKey = strcat(VariableGroupId, "-", ActorUserId)
| project UserKey;
ADOAuditLogs
| where TimeGenerated > ago(timeframe)
| where OperationName =~ "Library.VariableGroupModified"
| extend VariableGroupName = tostring(Data.VariableGroupName)
| extend VariableGroupId = tostring(Data.VariableGroupId)
| extend UserKey = strcat(VariableGroupId, "-", ActorUserId)
| where UserKey !in (historical_data)
| project-away UserKey
| project-reorder TimeGenerated, VariableGroupName, ActorUPN, IpAddress, UserAgent
| extend timestamp = TimeGenerated
| extend AccountName = tostring(split(ActorUPN, "@")[0]), AccountUPNSuffix = tostring(split(ActorUPN, "@")[1])
description: |
'Variables can be configured and used at any stage of the build process in Azure DevOps to inject values. An attacker with the required permissions could modify or add to these variables to conduct malicious activity such as changing paths or remote endpoints called during the build.
As variables are often changed by users, just detecting these changes would have a high false positive rate. This detection looks for modifications to variable groups where that user has not been observed modifying them before.'
severity: Medium
requiredDataConnectors: []
name: Azure DevOps Build Variable Modified by New User
triggerThreshold: 0
tactics:
- DefenseEvasion
version: 1.0.6
relevantTechniques:
- T1578
triggerOperator: gt
entityMappings:
- entityType: Account
fieldMappings:
- columnName: ActorUPN
identifier: FullName
- columnName: AccountName
identifier: Name
- columnName: AccountUPNSuffix
identifier: UPNSuffix
- entityType: IP
fieldMappings:
- columnName: IpAddress
identifier: Address
id: 3b9a44d7-c651-45ed-816c-eae583a6f2f1
status: Available
kind: Scheduled
queryFrequency: 1d
queryPeriod: 14d
{
"$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/3b9a44d7-c651-45ed-816c-eae583a6f2f1')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/3b9a44d7-c651-45ed-816c-eae583a6f2f1')]",
"properties": {
"alertRuleTemplateName": "3b9a44d7-c651-45ed-816c-eae583a6f2f1",
"customDetails": null,
"description": "'Variables can be configured and used at any stage of the build process in Azure DevOps to inject values. An attacker with the required permissions could modify or add to these variables to conduct malicious activity such as changing paths or remote endpoints called during the build.\nAs variables are often changed by users, just detecting these changes would have a high false positive rate. This detection looks for modifications to variable groups where that user has not been observed modifying them before.'\n",
"displayName": "Azure DevOps Build Variable Modified by New User",
"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/ADOVariableModifiedByNewUser.yaml",
"query": "let lookback = 14d;\nlet timeframe = 1d;\nlet historical_data =\nADOAuditLogs\n| where TimeGenerated > ago(lookback) and TimeGenerated < ago(timeframe)\n| where OperationName =~ \"Library.VariableGroupModified\"\n| extend variables = Data.Variables\n| extend VariableGroupId = tostring(Data.VariableGroupId)\n| extend UserKey = strcat(VariableGroupId, \"-\", ActorUserId)\n| project UserKey;\nADOAuditLogs\n| where TimeGenerated > ago(timeframe)\n| where OperationName =~ \"Library.VariableGroupModified\"\n| extend VariableGroupName = tostring(Data.VariableGroupName)\n| extend VariableGroupId = tostring(Data.VariableGroupId)\n| extend UserKey = strcat(VariableGroupId, \"-\", ActorUserId)\n| where UserKey !in (historical_data)\n| project-away UserKey\n| project-reorder TimeGenerated, VariableGroupName, ActorUPN, IpAddress, UserAgent\n| extend timestamp = TimeGenerated\n| extend AccountName = tostring(split(ActorUPN, \"@\")[0]), AccountUPNSuffix = tostring(split(ActorUPN, \"@\")[1])\n",
"queryFrequency": "P1D",
"queryPeriod": "P14D",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"DefenseEvasion"
],
"techniques": [
"T1578"
],
"templateVersion": "1.0.6",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}