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

triggerOperator: gt
queryFrequency: 1d
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
relevantTechniques:
- T1036.003
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
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  
triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/RenameSystemUtilities.yaml
queryPeriod: 1d
name: Rename System Utilities
status: Available
kind: Scheduled
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.  
id: 335ddff8-b615-42cd-b593-86e419b45d78
version: 1.0.0
tactics:
- DefenseEvasion
severity: Medium