Detect Registry Run Keys / Startup Folder in CrowdStrike LogScale
Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key. Adding an entry to the 'run keys' in the Registry or startup folder will cause the program referenced to be executed when a user logs in. These programs will be executed under the context of the user and will have the account's associated permissions level. The following run keys are created by default on Windows systems: HKCU\Software\Microsoft\Windows\CurrentVersion\Run, HKCU\Software\Microsoft\Windows\CurrentVersion\RunOnce, HKLM\Software\Microsoft\Windows\CurrentVersion\Run, and HKLM\Software\Microsoft\Windows\CurrentVersion\RunOnce. Additional persistence can be achieved through the Startup folder at C:\Users\[Username]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs\Startup and the system-wide C:\ProgramData\Microsoft\Windows\Start Menu\Programs\StartUp. The BootExecute value under Session Manager and the load value under HKCU\Software\Microsoft\Windows NT\CurrentVersion\Windows are also abusable.
MITRE ATT&CK
- Tactic
- Persistence Privilege Escalation
- Technique
- T1547 Boot or Logon Autostart Execution
- Sub-technique
- T1547.001 Registry Run Keys / Startup Folder
- Canonical reference
- https://attack.mitre.org/techniques/T1547/001/
LogScale Detection Query
#event_simpleName=RegValueSet
| TargetRegistryKey = /(?i)(CurrentVersion\\Run|CurrentVersion\\RunOnce|CurrentVersion\\RunOnceEx|CurrentVersion\\RunServices|CurrentVersion\\RunServicesOnce|Policies\\Explorer\\Run|Windows NT\\CurrentVersion\\Windows|Control\\Session Manager\\BootExecute)/
| ImageFileName != /(?i)(\\msiexec\.exe$|\\TrustedInstaller\.exe$|\\TiWorker\.exe$|\\ccmexec\.exe$|\\MpSigStub\.exe$)/
| SuspiciousPath := if(TargetRegistryValueData = /(?i)(\\Temp\\|\\AppData\\Local\\Temp|\\Downloads\\|\\Public\\|Recycle\.Bin|\\ProgramData\\)/, "true", "false")
| ScriptExt := if(TargetRegistryValueData = /(?i)\.(vbs|js|bat|cmd|ps1|hta|wsh|wsf)("| |$)/, "true", "false")
| SuspiciousPath = "true" OR ScriptExt = "true"
| RiskScore := if(SuspiciousPath = "true" AND ScriptExt = "true", "HIGH", if(SuspiciousPath = "true" OR ScriptExt = "true", "MEDIUM", "LOW"))
| table([timestamp, ComputerName, UserSid, TargetRegistryKey, TargetRegistryValueName, TargetRegistryValueData, ImageFileName, CommandLine, SuspiciousPath, ScriptExt, RiskScore])
| sort(field=timestamp, order=desc)CrowdStrike LogScale (Falcon) query over RegValueSet telemetry events detecting writes to Registry Run Key autorun paths from non-trusted processes where the registered value data references suspicious writable directories or script file types. Computes a composite risk score for analyst prioritization.
Data Sources
Required Tables
False Positives & Tuning
- Software auto-updaters (Chrome, Firefox, Adobe) that temporarily write update launcher paths referencing versioned subdirectories within ProgramData or LocalAppData during update cycles
- RMM (Remote Monitoring and Management) tools such as ConnectWise, NinjaRMM, or Datto that install persistent agent launchers via run keys, sometimes using .cmd or .bat wrappers
- Developer workstations running local testing of persistence mechanisms as part of red team tooling validation, purple team exercises, or application self-update testing pipelines
Other platforms for T1547.001
Testing Methodology
Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Registry Run Key Persistence (HKCU)
Expected signal: Sysmon Event ID 13: RegistryValueSet on HKCU\Software\Microsoft\Windows\CurrentVersion\Run with ValueName 'df00tech-test' and Details 'C:\Windows\System32\calc.exe'. MDE DeviceRegistryEvents with ActionType 'RegistryValueSet'.
- Test 2Startup Folder Persistence via Batch Script
Expected signal: Sysmon Event ID 11: FileCreate for df00tech-test.bat in the Startup folder path. Security Event ID 4688 showing cmd.exe creating the file.
- Test 3RunOnceEx Dependency DLL Loading
Expected signal: Sysmon Event ID 12: Registry key created for RunOnceEx\0001\Depend. Sysmon Event ID 13: Value set with DLL path. MDE DeviceRegistryEvents captures both the key creation and value set.
- Test 4HKLM Run Key via PowerShell
Expected signal: Sysmon Event ID 13: RegistryValueSet with Image=powershell.exe. Sysmon Event ID 1: Process creation for powershell.exe with the Set-ItemProperty command. PowerShell ScriptBlock Log Event ID 4104.
References (8)
- https://attack.mitre.org/techniques/T1547/001/
- https://learn.microsoft.com/en-us/windows/win32/setupapi/run-and-runonce-registry-keys
- https://oddvar.moe/2018/03/21/persistence-using-runonceex-hidden-from-autoruns-exe/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1547.001/T1547.001.md
- https://github.com/SigmaHQ/sigma/tree/master/rules/windows/registry_set
- https://web.archive.org/web/20160214140250/http://blog.cylance.com/windows-registry-persistence-part-2-the-run-keys-and-search-order
- https://docs.microsoft.com/en-us/windows/win32/sysinfo/32-bit-and-64-bit-application-data-in-the-registry
- https://blog.malwarebytes.com/cybercrime/2013/10/hiding-in-plain-sight/
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