Svchost LOLBAS Execution Process Spawn
Description
The following analytic detects instances of 'svchost.exe' spawning Living Off The Land Binaries and Scripts (LOLBAS) processes. It leverages Endpoint Detection and Response (EDR) data to monitor child processes of 'svchost.exe' that match known LOLBAS executables. This activity is significant as adversaries often use LOLBAS techniques to execute malicious code stealthily, potentially indicating lateral movement or code execution attempts. If confirmed malicious, this behavior could allow attackers to execute arbitrary commands, escalate privileges, or maintain persistence within the environment, posing a significant security risk.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
FROM datamodel=Endpoint.Processes WHERE
Processes.parent_process = "*"
Processes.parent_process_name = "svchost.exe"
Processes.process_name IN (
"At.exe", "Atbroker.exe", "Bash.exe", "Bitsadmin.exe", "Certoc.exe", "Cmstp.exe",
"Diskshadow.exe", "Dnscmd.exe", "Extexport.exe", "Forfiles.exe", "Ftp.exe",
"Gpscript.exe", "Hh.exe", "Ie4uinit.exe", "Ieexec.exe", "Infdefaultinstall.exe",
"Installutil.exe", "Mavinject.exe", "Microsoft.Workflow.Compiler.exe",
"Msbuild.exe", "Msconfig.exe", "Msdt.exe", "Msiexec.exe", "Netsh.exe",
"Odbcconf.exe", "OfflineScannerShell.exe", "Pcalua.exe", "Pcwrun.exe",
"Pnputil.exe", "PresentationHost.exe", "Rasautou.exe", "Regasm.exe",
"Register-cimprovider.exe", "Regsvcs.exe", "Regsvr32.exe", "Runonce.exe",
"Runscripthelper.exe", "Schtasks.exe", "Scriptrunner.exe", "SettingSyncHost.exe",
"Stordiag.exe", "Syncappvpublishingserver.exe", "Ttdinject.exe", "Mshta.exe",
"Tttracer.exe", "Verclsid.exe", "Wab.exe", "Wmic.exe",
"WorkFolders.exe", "Wuauclt.exe", "Xwizard.exe"
)
NOT (
Processes.parent_process IN ("*-k GPSvcGroup*", "*-k netsvcs", "*-k netsvcs -p","*-k netsvcs -p -s gpsvc")
Processes.process_name = "Gpscript.exe"
)
NOT (
Processes.parent_process IN ("*-k netsvcs", "*-k netsvcs -p", "*-k netsvcs -p -s wuauserv", "-k netsvcs -p -s Schedule")
Processes.process_name IN ("Wuauclt.exe", "Schtasks.exe")
)
NOT (
Processes.parent_process = "*-k DcomLaunch*"
Processes.process_name IN ("PresentationHost.exe", "SettingSyncHost.exe")
)
BY Processes.action Processes.dest Processes.original_file_name
Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path Processes.user
Processes.user_id Processes.vendor_product
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `svchost_lolbas_execution_process_spawn_filter`
Implementation guide
The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.
Known false positives
- Legitimate applications may trigger this behavior, filter as needed.
Analyst notes
Known false positives: Legitimate applications may trigger this behavior, filter as needed.