Windows Application Whitelisting Bypass Attempt via Rundll32
Description
The following analytic detects the execution of rundll32.exe calling one of the following DLLs:
- Advpack.dll
- Ieadvpack.dll
- Syssetup.dll
- Setupapi.dll
with one of the following functions: "LaunchINFSection", "InstallHinfSection", "SetupInfObjectInstallAction". This method is identified through Endpoint Detection and Response (EDR) telemetry, focusing on command-line executions and process details. This activity is significant as it indicates a potential application control or whitelisting bypass, allowing script code execution from a file. If confirmed malicious, an attacker could execute arbitrary code, potentially leading to privilege escalation, persistence, or further network compromise. Investigate the script content, network connections, and any spawned child processes for further context.
Query · spl
| tstats `security_content_summariesonly`
count min(_time) as firstTime
max(_time) as lastTime
from datamodel=Endpoint.Processes where
`process_rundll32`
Processes.process IN ("*syssetup*", "*advpack*", "*setupapi*")
Processes.process IN ("*LaunchINFSection*", "*InstallHinfSection*", "*SetupInfObjectInstallAction*")
NOT (Processes.parent_process_name="msiexec.exe" Processes.process="* C:\\Program Files (x86)\\Netskope\\EPDLP Deployment\\*")
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)`
| `windows_application_whitelisting_bypass_attempt_via_rundll32_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
- Although unlikely, some legitimate applications may leverage one of the following DLLs syssetup.dll, dvpack.dll, ieadvpack.dll and can trigger a false positive. Apply additional filters as needed.
Analyst notes
Known false positives: Although unlikely, some legitimate applications may leverage one of the following DLLs syssetup.dll, dvpack.dll, ieadvpack.dll and can trigger a false positive. Apply additional filters as needed.