Base64 encoded Windows process command-lines
Id | ca67c83e-7fff-4127-a3e3-1af66d6d4cad |
Rulename | Base64 encoded Windows process command-lines |
Description | Identifies instances of a base64 encoded PE file header seen in the process command line parameter. |
Severity | Medium |
Tactics | Execution DefenseEvasion |
Techniques | T1059 T1027 T1140 |
Required data connectors | SecurityEvents WindowsForwardedEvents WindowsSecurityEvents |
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/Endpoint Threat Protection Essentials/Analytic Rules/base64_encoded_pefile.yaml |
Version | 1.1.2 |
Arm template | ca67c83e-7fff-4127-a3e3-1af66d6d4cad.json |
let ProcessCreationEvents=() {
let processEvents=(union isfuzzy=true
(SecurityEvent
| where EventID==4688
| where isnotempty(CommandLine)
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,
FileName = Process, CommandLine, ParentProcessName
),
(WindowsEvent
| where EventID==4688
| where EventData has "TVqQAAMAAAAEAAA"
| extend CommandLine = tostring(EventData.CommandLine)
| where isnotempty(CommandLine)
| extend ParentProcessName = tostring(EventData.ParentProcessName)
| extend NewProcessName = tostring(EventData.NewProcessName)
| extend Process=tostring(split(NewProcessName, '\\')[-1])
| extend SubjectUserName = tostring(EventData.SubjectUserName)
| extend SubjectDomainName = tostring(EventData.SubjectDomainName)
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,
FileName = Process, CommandLine, ParentProcessName));
processEvents};
ProcessCreationEvents
| where CommandLine contains "TVqQAAMAAAAEAAA"
| extend timestamp = StartTimeUtc, AccountCustomEntity = Account, HostCustomEntity = Computer
tactics:
- Execution
- DefenseEvasion
severity: Medium
requiredDataConnectors:
- connectorId: SecurityEvents
dataTypes:
- SecurityEvent
- connectorId: WindowsSecurityEvents
dataTypes:
- SecurityEvent
- connectorId: WindowsSecurityEvents
dataTypes:
- SecurityEvents
- connectorId: WindowsForwardedEvents
dataTypes:
- WindowsEvent
triggerOperator: gt
query: |
let ProcessCreationEvents=() {
let processEvents=(union isfuzzy=true
(SecurityEvent
| where EventID==4688
| where isnotempty(CommandLine)
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,
FileName = Process, CommandLine, ParentProcessName
),
(WindowsEvent
| where EventID==4688
| where EventData has "TVqQAAMAAAAEAAA"
| extend CommandLine = tostring(EventData.CommandLine)
| where isnotempty(CommandLine)
| extend ParentProcessName = tostring(EventData.ParentProcessName)
| extend NewProcessName = tostring(EventData.NewProcessName)
| extend Process=tostring(split(NewProcessName, '\\')[-1])
| extend SubjectUserName = tostring(EventData.SubjectUserName)
| extend SubjectDomainName = tostring(EventData.SubjectDomainName)
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,
FileName = Process, CommandLine, ParentProcessName));
processEvents};
ProcessCreationEvents
| where CommandLine contains "TVqQAAMAAAAEAAA"
| extend timestamp = StartTimeUtc, AccountCustomEntity = Account, HostCustomEntity = Computer
triggerThreshold: 0
name: Base64 encoded Windows process command-lines
kind: Scheduled
version: 1.1.2
relevantTechniques:
- T1059
- T1027
- T1140
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Endpoint Threat Protection Essentials/Analytic Rules/base64_encoded_pefile.yaml
description: |
'Identifies instances of a base64 encoded PE file header seen in the process command line parameter.'
status: Available
queryFrequency: 1d
queryPeriod: 1d
entityMappings:
- entityType: Account
fieldMappings:
- identifier: FullName
columnName: AccountCustomEntity
- entityType: Host
fieldMappings:
- identifier: FullName
columnName: HostCustomEntity
id: ca67c83e-7fff-4127-a3e3-1af66d6d4cad
{
"$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/ca67c83e-7fff-4127-a3e3-1af66d6d4cad')]",
"name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/ca67c83e-7fff-4127-a3e3-1af66d6d4cad')]",
"type": "Microsoft.OperationalInsights/workspaces/providers/alertRules",
"kind": "Scheduled",
"apiVersion": "2022-11-01",
"properties": {
"displayName": "Base64 encoded Windows process command-lines",
"description": "'Identifies instances of a base64 encoded PE file header seen in the process command line parameter.'\n",
"severity": "Medium",
"enabled": true,
"query": "let ProcessCreationEvents=() {\nlet processEvents=(union isfuzzy=true\n(SecurityEvent\n| where EventID==4688\n| where isnotempty(CommandLine)\n| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,\nFileName = Process, CommandLine, ParentProcessName\n),\n(WindowsEvent\n| where EventID==4688\n| where EventData has \"TVqQAAMAAAAEAAA\"\n| extend CommandLine = tostring(EventData.CommandLine)\n| where isnotempty(CommandLine)\n| extend ParentProcessName = tostring(EventData.ParentProcessName)\n| extend NewProcessName = tostring(EventData.NewProcessName)\n| extend Process=tostring(split(NewProcessName, '\\\\')[-1])\n| extend SubjectUserName = tostring(EventData.SubjectUserName)\n| extend SubjectDomainName = tostring(EventData.SubjectDomainName)\n| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), count() by Computer, Account = SubjectUserName, AccountDomain = SubjectDomainName,\nFileName = Process, CommandLine, ParentProcessName));\nprocessEvents};\nProcessCreationEvents\n| where CommandLine contains \"TVqQAAMAAAAEAAA\"\n| extend timestamp = StartTimeUtc, AccountCustomEntity = Account, HostCustomEntity = Computer\n",
"queryFrequency": "P1D",
"queryPeriod": "P1D",
"triggerOperator": "GreaterThan",
"triggerThreshold": 0,
"suppressionDuration": "PT1H",
"suppressionEnabled": false,
"tactics": [
"Execution",
"DefenseEvasion"
],
"techniques": [
"T1059",
"T1027",
"T1140"
],
"alertRuleTemplateName": "ca67c83e-7fff-4127-a3e3-1af66d6d4cad",
"customDetails": null,
"entityMappings": [
{
"fieldMappings": [
{
"columnName": "AccountCustomEntity",
"identifier": "FullName"
}
],
"entityType": "Account"
},
{
"fieldMappings": [
{
"columnName": "HostCustomEntity",
"identifier": "FullName"
}
],
"entityType": "Host"
}
],
"status": "Available",
"templateVersion": "1.1.2",
"OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Endpoint Threat Protection Essentials/Analytic Rules/base64_encoded_pefile.yaml"
}
}
]
}