Rename System Utilities

// Removed update.exe as LOLBIN. It's a way too generic name and causes a lot of noise. 
let lolbin = dynamic(["At.exe", "Atbroker.exe", "Bash.exe", "Bitsadmin.exe", "CertReq.exe", "Certutil.exe", "Cmd.exe", "Cmdkey.exe", "Cmstp.exe", "Control.exe", "Csc.exe", "Cscript.exe", "Desktopimgdownldr.exe", "Dfsvc.exe", "Diantz.exe", "Diskshadow.exe", "Dnscmd.exe", "Esentutl.exe", "Eventvwr.exe", "Expand.exe", "Extexport.exe", "Extrac32.exe", "Findstr.exe", "Forfiles.exe", "Ftp.exe", "GfxDownloadWrapper.exe", "Gpscript.exe", "Hh.exe", "Ie4uinit.exe", "Ieexec.exe", "Ilasm.exe", "Infdefaultinstall.exe", "Installutil.exe", "Jsc.exe", "Makecab.exe", "Mavinject.exe", "Microsoft.Workflow.Compiler.exe", "Mmc.exe", "MpCmdRun.exe", "Msbuild.exe", "Msconfig.exe", "Msdt.exe", "Mshta.exe", "Msiexec.exe", "Netsh.exe", "Odbcconf.exe", "Pcalua.exe", "Pcwrun.exe", "Pktmon.exe", "Presentationhost.exe", "Print.exe", "Psr.exe", "Rasautou.exe", "Reg.exe", "Regasm.exe", "Regedit.exe", "Regini.exe", "Register-cimprovider.exe", "Regsvcs.exe", "Regsvr32.exe", "Replace.exe", "Rpcping.exe", "Rundll32.exe", "Runonce.exe", "Runscripthelper.exe", "Sc.exe", "Schtasks.exe", "Scriptrunner.exe", "SyncAppvPublishingServer.exe", "Ttdinject.exe", "Tttracer.exe", "vbc.exe", "Verclsid.exe", "Wab.exe", "Wmic.exe", "Wscript.exe", "Wsreset.exe", "Xwizard.exe", "AgentExecutor.exe", "Appvlp.exe", "Bginfo.exe", "Cdb.exe", "csi.exe", "Devtoolslauncher.exe", "dnx.exe", "Dotnet.exe", "Dxcap.exe", "Excel.exe", "Mftrace.exe", "Msdeploy.exe", "msxsl.exe", "ntdsutil.exe", "Powerpnt.exe", "rcsi.exe", "Sqldumper.exe", "Sqlps.exe", "SQLToolsPS.exe", "Squirrel.exe", "te.exe", "Tracker.exe", "vsjitdebugger.exe", "Winword.exe", "Wsl.exe"]); 
let allHashesLolbin = materialize(
DeviceProcessEvents
| where FileName in~ (lolbin) and not(isempty(SHA1))
| extend OriginalFilename = tolower(FileName)
| summarize by SHA1, OriginalFilename);
allHashesLolbin
| join kind=inner hint.strategy = broadcast DeviceProcessEvents on SHA1
| where FileName !~ OriginalFilename
| where not(OriginalFilename =~ "bash.exe" and FileName =~ "sh.exe")
| extend message=strcat("Usage of ", OriginalFilename, ". Renamed as ", FileName)
| project-reorder message

kind: Scheduled
triggerThreshold: 0
tactics:
- DefenseEvasion
id: 335ddff8-b615-42cd-b593-86e419b45d78
query: |
  // Removed update.exe as LOLBIN. It's a way too generic name and causes a lot of noise. 
  let lolbin = dynamic(["At.exe", "Atbroker.exe", "Bash.exe", "Bitsadmin.exe", "CertReq.exe", "Certutil.exe", "Cmd.exe", "Cmdkey.exe", "Cmstp.exe", "Control.exe", "Csc.exe", "Cscript.exe", "Desktopimgdownldr.exe", "Dfsvc.exe", "Diantz.exe", "Diskshadow.exe", "Dnscmd.exe", "Esentutl.exe", "Eventvwr.exe", "Expand.exe", "Extexport.exe", "Extrac32.exe", "Findstr.exe", "Forfiles.exe", "Ftp.exe", "GfxDownloadWrapper.exe", "Gpscript.exe", "Hh.exe", "Ie4uinit.exe", "Ieexec.exe", "Ilasm.exe", "Infdefaultinstall.exe", "Installutil.exe", "Jsc.exe", "Makecab.exe", "Mavinject.exe", "Microsoft.Workflow.Compiler.exe", "Mmc.exe", "MpCmdRun.exe", "Msbuild.exe", "Msconfig.exe", "Msdt.exe", "Mshta.exe", "Msiexec.exe", "Netsh.exe", "Odbcconf.exe", "Pcalua.exe", "Pcwrun.exe", "Pktmon.exe", "Presentationhost.exe", "Print.exe", "Psr.exe", "Rasautou.exe", "Reg.exe", "Regasm.exe", "Regedit.exe", "Regini.exe", "Register-cimprovider.exe", "Regsvcs.exe", "Regsvr32.exe", "Replace.exe", "Rpcping.exe", "Rundll32.exe", "Runonce.exe", "Runscripthelper.exe", "Sc.exe", "Schtasks.exe", "Scriptrunner.exe", "SyncAppvPublishingServer.exe", "Ttdinject.exe", "Tttracer.exe", "vbc.exe", "Verclsid.exe", "Wab.exe", "Wmic.exe", "Wscript.exe", "Wsreset.exe", "Xwizard.exe", "AgentExecutor.exe", "Appvlp.exe", "Bginfo.exe", "Cdb.exe", "csi.exe", "Devtoolslauncher.exe", "dnx.exe", "Dotnet.exe", "Dxcap.exe", "Excel.exe", "Mftrace.exe", "Msdeploy.exe", "msxsl.exe", "ntdsutil.exe", "Powerpnt.exe", "rcsi.exe", "Sqldumper.exe", "Sqlps.exe", "SQLToolsPS.exe", "Squirrel.exe", "te.exe", "Tracker.exe", "vsjitdebugger.exe", "Winword.exe", "Wsl.exe"]); 
  let allHashesLolbin = materialize(
  DeviceProcessEvents
  | where FileName in~ (lolbin) and not(isempty(SHA1))
  | extend OriginalFilename = tolower(FileName)
  | summarize by SHA1, OriginalFilename);
  allHashesLolbin
  | join kind=inner hint.strategy = broadcast DeviceProcessEvents on SHA1
  | where FileName !~ OriginalFilename
  | where not(OriginalFilename =~ "bash.exe" and FileName =~ "sh.exe")
  | extend message=strcat("Usage of ", OriginalFilename, ". Renamed as ", FileName)
  | project-reorder message  
requiredDataConnectors:
- dataTypes:
  - DeviceProcessEvents
  connectorId: MicrosoftThreatProtection
name: Rename System Utilities
entityMappings:
- entityType: Host
  fieldMappings:
  - identifier: FullName
    columnName: DeviceName
- entityType: Account
  fieldMappings:
  - identifier: Sid
    columnName: AccountSid
  - identifier: Name
    columnName: AccountName
  - identifier: NTDomain
    columnName: AccountDomain
- entityType: Process
  fieldMappings:
  - identifier: CommandLine
    columnName: ProcessCommandLine
status: Available
description: |
  Attackers often use LOLBINs that are renamed to avoid detection rules that are based on filenames.
  This rule detects renamed LOLBINs by first searching for all the known SHA1 hashes of the LOLBINs in your DeviceProcessEvents. This list is then used as reference to find other files executed which have a name that doesn't match the original filename. 
  This query is really heavy on resources. Use it with care.  
severity: Medium
queryFrequency: 1d
version: 1.0.0
triggerOperator: gt
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/RenameSystemUtilities.yaml
relevantTechniques:
- T1036.003
queryPeriod: 1d

{
  "$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/335ddff8-b615-42cd-b593-86e419b45d78')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/335ddff8-b615-42cd-b593-86e419b45d78')]",
      "properties": {
        "alertRuleTemplateName": "335ddff8-b615-42cd-b593-86e419b45d78",
        "customDetails": null,
        "description": "Attackers often use LOLBINs that are renamed to avoid detection rules that are based on filenames.\nThis rule detects renamed LOLBINs by first searching for all the known SHA1 hashes of the LOLBINs in your DeviceProcessEvents. This list is then used as reference to find other files executed which have a name that doesn't match the original filename. \nThis query is really heavy on resources. Use it with care.\n",
        "displayName": "Rename System Utilities",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "DeviceName",
                "identifier": "FullName"
              }
            ]
          },
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "AccountSid",
                "identifier": "Sid"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Process",
            "fieldMappings": [
              {
                "columnName": "ProcessCommandLine",
                "identifier": "CommandLine"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/RenameSystemUtilities.yaml",
        "query": "// Removed update.exe as LOLBIN. It's a way too generic name and causes a lot of noise. \nlet lolbin = dynamic([\"At.exe\", \"Atbroker.exe\", \"Bash.exe\", \"Bitsadmin.exe\", \"CertReq.exe\", \"Certutil.exe\", \"Cmd.exe\", \"Cmdkey.exe\", \"Cmstp.exe\", \"Control.exe\", \"Csc.exe\", \"Cscript.exe\", \"Desktopimgdownldr.exe\", \"Dfsvc.exe\", \"Diantz.exe\", \"Diskshadow.exe\", \"Dnscmd.exe\", \"Esentutl.exe\", \"Eventvwr.exe\", \"Expand.exe\", \"Extexport.exe\", \"Extrac32.exe\", \"Findstr.exe\", \"Forfiles.exe\", \"Ftp.exe\", \"GfxDownloadWrapper.exe\", \"Gpscript.exe\", \"Hh.exe\", \"Ie4uinit.exe\", \"Ieexec.exe\", \"Ilasm.exe\", \"Infdefaultinstall.exe\", \"Installutil.exe\", \"Jsc.exe\", \"Makecab.exe\", \"Mavinject.exe\", \"Microsoft.Workflow.Compiler.exe\", \"Mmc.exe\", \"MpCmdRun.exe\", \"Msbuild.exe\", \"Msconfig.exe\", \"Msdt.exe\", \"Mshta.exe\", \"Msiexec.exe\", \"Netsh.exe\", \"Odbcconf.exe\", \"Pcalua.exe\", \"Pcwrun.exe\", \"Pktmon.exe\", \"Presentationhost.exe\", \"Print.exe\", \"Psr.exe\", \"Rasautou.exe\", \"Reg.exe\", \"Regasm.exe\", \"Regedit.exe\", \"Regini.exe\", \"Register-cimprovider.exe\", \"Regsvcs.exe\", \"Regsvr32.exe\", \"Replace.exe\", \"Rpcping.exe\", \"Rundll32.exe\", \"Runonce.exe\", \"Runscripthelper.exe\", \"Sc.exe\", \"Schtasks.exe\", \"Scriptrunner.exe\", \"SyncAppvPublishingServer.exe\", \"Ttdinject.exe\", \"Tttracer.exe\", \"vbc.exe\", \"Verclsid.exe\", \"Wab.exe\", \"Wmic.exe\", \"Wscript.exe\", \"Wsreset.exe\", \"Xwizard.exe\", \"AgentExecutor.exe\", \"Appvlp.exe\", \"Bginfo.exe\", \"Cdb.exe\", \"csi.exe\", \"Devtoolslauncher.exe\", \"dnx.exe\", \"Dotnet.exe\", \"Dxcap.exe\", \"Excel.exe\", \"Mftrace.exe\", \"Msdeploy.exe\", \"msxsl.exe\", \"ntdsutil.exe\", \"Powerpnt.exe\", \"rcsi.exe\", \"Sqldumper.exe\", \"Sqlps.exe\", \"SQLToolsPS.exe\", \"Squirrel.exe\", \"te.exe\", \"Tracker.exe\", \"vsjitdebugger.exe\", \"Winword.exe\", \"Wsl.exe\"]); \nlet allHashesLolbin = materialize(\nDeviceProcessEvents\n| where FileName in~ (lolbin) and not(isempty(SHA1))\n| extend OriginalFilename = tolower(FileName)\n| summarize by SHA1, OriginalFilename);\nallHashesLolbin\n| join kind=inner hint.strategy = broadcast DeviceProcessEvents on SHA1\n| where FileName !~ OriginalFilename\n| where not(OriginalFilename =~ \"bash.exe\" and FileName =~ \"sh.exe\")\n| extend message=strcat(\"Usage of \", OriginalFilename, \". Renamed as \", FileName)\n| project-reorder message\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [
          "T1036.003"
        ],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1036"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}