Potential Build Process Compromise - MDE
Id | 1bf6e165-5e32-420e-ab4f-0da8558a8be2 |
Rulename | Potential Build Process Compromise - MDE |
Description | The query looks for source code files being modified immediately after a build process is started. The purpose of this is to look for malicious code injection during the build process. This query uses Microsoft Defender for Endpoint telemetry. More details: https://techcommunity.microsoft.com/t5/azure-sentinel/monitoring-the-software-supply-chain-with-azure-sentinel/ba-p/2176463 |
Severity | Medium |
Tactics | Persistence |
Techniques | T1554 |
Required data connectors | MicrosoftThreatProtection |
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/Microsoft Defender XDR/Analytic Rules/PotentialBuildProcessCompromiseMDE.yaml |
Version | 1.1.0 |
Arm template | 1bf6e165-5e32-420e-ab4f-0da8558a8be2.json |
// How far back to look for events from
let timeframe = 1d;
// How close together build events and file modifications should occur to alert (make this smaller to reduce FPs)
let time_window = 5m;
// Edit this to include build processes used
let build_processes = dynamic(["MSBuild.exe", "dotnet.exe", "VBCSCompiler.exe"]);
// Include any processes that you want to allow to edit files during/around the build process
let allow_list = dynamic([]);
DeviceProcessEvents
| where TimeGenerated > ago(timeframe)
// Look for build process starts
| where FileName has_any (build_processes)
| summarize by BuildParentProcess=InitiatingProcessFileName, BuildProcess=FileName, BuildAccount = AccountName, DeviceName, BuildCommand=ProcessCommandLine,
timekey= bin(TimeGenerated, time_window), BuildProcessTime=TimeGenerated
| join kind=inner(
DeviceFileEvents
| where TimeGenerated > ago(timeframe)
| where InitiatingProcessFileName !in (allow_list)
| where ActionType == "FileCreated" or ActionType == "FileModified"
// Look for code files, edit this to include file extensions used in build.
| where FileName endswith ".cs" or FileName endswith ".cpp"
| summarize by FileEditParentProcess=InitiatingProcessParentFileName, FileEditAccount = InitiatingProcessAccountName, FileEditDomain = InitiatingProcessAccountDomain, FileEditUpn = InitiatingProcessAccountUpn,
DeviceName, FileEdited=FileName, FileEditProcess=InitiatingProcessFileName, timekey= bin(TimeGenerated, time_window), FileEditTime=TimeGenerated)
// join where build processes and file modifications seen at same time on same host
on timekey, DeviceName
// Limit to only where the file edit happens after the build process starts
| where BuildProcessTime <= FileEditTime
| summarize make_set(FileEdited), make_set(FileEditProcess) by timekey, DeviceName, BuildParentProcess, BuildProcess, FileEditAccount, FileEditDomain, FileEditUpn
| extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)
queryPeriod: 1d
version: 1.1.0
tactics:
- Persistence
queryFrequency: 1d
id: 1bf6e165-5e32-420e-ab4f-0da8558a8be2
triggerOperator: gt
requiredDataConnectors:
- dataTypes:
- DeviceProcessEvents
- DeviceFileEvents
connectorId: MicrosoftThreatProtection
severity: Medium
entityMappings:
- entityType: Host
fieldMappings:
- columnName: HostName
identifier: HostName
- columnName: HostNameDomain
identifier: DnsDomain
- entityType: Account
fieldMappings:
- columnName: FileEditUpn
identifier: FullName
- columnName: FileEditAccount
identifier: Name
- columnName: FileEditDomain
identifier: UPNSuffix
triggerThreshold: 0
relevantTechniques:
- T1554
query: |
// How far back to look for events from
let timeframe = 1d;
// How close together build events and file modifications should occur to alert (make this smaller to reduce FPs)
let time_window = 5m;
// Edit this to include build processes used
let build_processes = dynamic(["MSBuild.exe", "dotnet.exe", "VBCSCompiler.exe"]);
// Include any processes that you want to allow to edit files during/around the build process
let allow_list = dynamic([]);
DeviceProcessEvents
| where TimeGenerated > ago(timeframe)
// Look for build process starts
| where FileName has_any (build_processes)
| summarize by BuildParentProcess=InitiatingProcessFileName, BuildProcess=FileName, BuildAccount = AccountName, DeviceName, BuildCommand=ProcessCommandLine,
timekey= bin(TimeGenerated, time_window), BuildProcessTime=TimeGenerated
| join kind=inner(
DeviceFileEvents
| where TimeGenerated > ago(timeframe)
| where InitiatingProcessFileName !in (allow_list)
| where ActionType == "FileCreated" or ActionType == "FileModified"
// Look for code files, edit this to include file extensions used in build.
| where FileName endswith ".cs" or FileName endswith ".cpp"
| summarize by FileEditParentProcess=InitiatingProcessParentFileName, FileEditAccount = InitiatingProcessAccountName, FileEditDomain = InitiatingProcessAccountDomain, FileEditUpn = InitiatingProcessAccountUpn,
DeviceName, FileEdited=FileName, FileEditProcess=InitiatingProcessFileName, timekey= bin(TimeGenerated, time_window), FileEditTime=TimeGenerated)
// join where build processes and file modifications seen at same time on same host
on timekey, DeviceName
// Limit to only where the file edit happens after the build process starts
| where BuildProcessTime <= FileEditTime
| summarize make_set(FileEdited), make_set(FileEditProcess) by timekey, DeviceName, BuildParentProcess, BuildProcess, FileEditAccount, FileEditDomain, FileEditUpn
| extend HostName = tostring(split(DeviceName, ".")[0]), DomainIndex = toint(indexof(DeviceName, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)
kind: Scheduled
name: Potential Build Process Compromise - MDE
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/PotentialBuildProcessCompromiseMDE.yaml
description: |
'The query looks for source code files being modified immediately after a build process is started. The purpose of this is to look for malicious code injection during the build process. This query uses Microsoft Defender for Endpoint telemetry.
More details: https://techcommunity.microsoft.com/t5/azure-sentinel/monitoring-the-software-supply-chain-with-azure-sentinel/ba-p/2176463'
status: Available
tags:
- Solorigate
- NOBELIUM
{
"$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/1bf6e165-5e32-420e-ab4f-0da8558a8be2')]",
"kind": "Scheduled",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/1bf6e165-5e32-420e-ab4f-0da8558a8be2')]",
"properties": {
"alertRuleTemplateName": "1bf6e165-5e32-420e-ab4f-0da8558a8be2",
"customDetails": null,
"description": "'The query looks for source code files being modified immediately after a build process is started. The purpose of this is to look for malicious code injection during the build process. This query uses Microsoft Defender for Endpoint telemetry.\nMore details: https://techcommunity.microsoft.com/t5/azure-sentinel/monitoring-the-software-supply-chain-with-azure-sentinel/ba-p/2176463'\n",
"displayName": "Potential Build Process Compromise - MDE",
"enabled": true,
"entityMappings": [
{
"entityType": "Host",
"fieldMappings": [
{
"columnName": "HostName",
"identifier": "HostName"
},
{
"columnName": "HostNameDomain",
"identifier": "DnsDomain"
}
]
},
{
"entityType": "Account",
"fieldMappings": [
{
"columnName": "FileEditUpn",
"identifier": "FullName"
},
{
"columnName": "FileEditAccount",
"identifier": "Name"
},
{
"columnName": "FileEditDomain",
"identifier": "UPNSuffix"
}
]
}
],
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/PotentialBuildProcessCompromiseMDE.yaml",
"query": "// How far back to look for events from\nlet timeframe = 1d;\n// How close together build events and file modifications should occur to alert (make this smaller to reduce FPs)\nlet time_window = 5m;\n// Edit this to include build processes used\nlet build_processes = dynamic([\"MSBuild.exe\", \"dotnet.exe\", \"VBCSCompiler.exe\"]);\n// Include any processes that you want to allow to edit files during/around the build process\nlet allow_list = dynamic([]);\nDeviceProcessEvents\n| where TimeGenerated > ago(timeframe)\n// Look for build process starts\n| where FileName has_any (build_processes)\n| summarize by BuildParentProcess=InitiatingProcessFileName, BuildProcess=FileName, BuildAccount = AccountName, DeviceName, BuildCommand=ProcessCommandLine, \ntimekey= bin(TimeGenerated, time_window), BuildProcessTime=TimeGenerated\n| join kind=inner(\nDeviceFileEvents\n| where TimeGenerated > ago(timeframe)\n| where InitiatingProcessFileName !in (allow_list)\n| where ActionType == \"FileCreated\" or ActionType == \"FileModified\"\n// Look for code files, edit this to include file extensions used in build.\n| where FileName endswith \".cs\" or FileName endswith \".cpp\"\n| summarize by FileEditParentProcess=InitiatingProcessParentFileName, FileEditAccount = InitiatingProcessAccountName, FileEditDomain = InitiatingProcessAccountDomain, FileEditUpn = InitiatingProcessAccountUpn, \nDeviceName, FileEdited=FileName, FileEditProcess=InitiatingProcessFileName, timekey= bin(TimeGenerated, time_window), FileEditTime=TimeGenerated)\n// join where build processes and file modifications seen at same time on same host\non timekey, DeviceName\n// Limit to only where the file edit happens after the build process starts\n| where BuildProcessTime <= FileEditTime\n| summarize make_set(FileEdited), make_set(FileEditProcess) by timekey, DeviceName, BuildParentProcess, BuildProcess, FileEditAccount, FileEditDomain, FileEditUpn\n| extend HostName = tostring(split(DeviceName, \".\")[0]), DomainIndex = toint(indexof(DeviceName, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(DeviceName, DomainIndex + 1), DeviceName)\n",
"queryFrequency": "P1D",
"queryPeriod": "P1D",
"severity": "Medium",
"status": "Available",
"subTechniques": [],
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Persistence"
],
"tags": [
"Solorigate",
"NOBELIUM"
],
"techniques": [
"T1554"
],
"templateVersion": "1.1.0",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0
},
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
}
]
}