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 | 1.0.1 |
Arm template | 3b9a44d7-c651-45ed-816c-eae583a6f2f1.json |
let lookback = 14d;
let timeframe = 1d;
let historical_data =
AzureDevOpsAuditing
| 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;
AzureDevOpsAuditing
| 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, AccountCustomEntity = ActorUPN, IPCustomEntity = IpAddress
version: 1.0.1
status: Available
queryFrequency: 1d
requiredDataConnectors: []
entityMappings:
- fieldMappings:
- columnName: AccountCustomEntity
identifier: FullName
entityType: Account
- fieldMappings:
- columnName: IPCustomEntity
identifier: Address
entityType: IP
kind: Scheduled
queryPeriod: 14d
severity: Medium
query: |
let lookback = 14d;
let timeframe = 1d;
let historical_data =
AzureDevOpsAuditing
| 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;
AzureDevOpsAuditing
| 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, AccountCustomEntity = ActorUPN, IPCustomEntity = IpAddress
triggerOperator: gt
id: 3b9a44d7-c651-45ed-816c-eae583a6f2f1
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.'
triggerThreshold: 0
name: Azure DevOps Build Variable Modified by New User.
relevantTechniques:
- T1578
tactics:
- DefenseEvasion
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADOVariableModifiedByNewUser.yaml
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"workspace": {
"type": "String"
}
},
"resources": [
{
"id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/3b9a44d7-c651-45ed-816c-eae583a6f2f1')]",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/3b9a44d7-c651-45ed-816c-eae583a6f2f1')]",
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
"kind": "Scheduled",
"apiVersion": "2022-11-01",
"properties": {
"displayName": "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 \nor 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, \njust 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 \nmodifying them before.'\n",
"severity": "Medium",
"enabled": true,
"query": "let lookback = 14d;\nlet timeframe = 1d;\nlet historical_data =\nAzureDevOpsAuditing\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;\nAzureDevOpsAuditing\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, AccountCustomEntity = ActorUPN, IPCustomEntity = IpAddress\n",
"queryFrequency": "P1D",
"queryPeriod": "P14D",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0,
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"DefenseEvasion"
],
"techniques": [
"T1578"
],
"alertRuleTemplateName": "3b9a44d7-c651-45ed-816c-eae583a6f2f1",
"customDetails": null,
"entityMappings": [
{
"entityType": "Account",
"fieldMappings": [
{
"identifier": "FullName",
"columnName": "AccountCustomEntity"
}
]
},
{
"entityType": "IP",
"fieldMappings": [
{
"identifier": "Address",
"columnName": "IPCustomEntity"
}
]
}
],
"status": "Available",
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/AzureDevOpsAuditing/Analytic Rules/ADOVariableModifiedByNewUser.yaml",
"templateVersion": "1.0.1"
}
}
]
}