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

relevantTechniques:
- T1036.003
entityMappings:
- fieldMappings:
  - columnName: DeviceName
    identifier: FullName
  entityType: Host
- fieldMappings:
  - columnName: AccountSid
    identifier: Sid
  - columnName: AccountName
    identifier: Name
  - columnName: AccountDomain
    identifier: NTDomain
  entityType: Account
- fieldMappings:
  - columnName: ProcessCommandLine
    identifier: CommandLine
  entityType: Process
triggerThreshold: 0
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.  
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
triggerOperator: gt
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/FalconFriday/Analytic Rules/RenameSystemUtilities.yaml
id: 335ddff8-b615-42cd-b593-86e419b45d78
queryFrequency: 1d
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  
severity: Medium
status: Available
queryPeriod: 1d
name: Rename System Utilities
tactics:
- DefenseEvasion
kind: Scheduled