The following hunting analytic will identify any protocol handlers utilized on the command-line. A protocol handler is an application that knows how to handle particular types of links: for example, a mail client is a protocol handler for "mailto:" links. When the user clicks a "mailto:" link, the browser opens the application selected as the handler for the "mailto:" protocol (or offers them a choice of handlers, depending on their settings). To identify protocol handlers we can use NirSoft https://www.nirsoft.net/utils/url_protocol_view.html URLProtocolView or query the registry using PowerShell.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2022-09-13
- Author: Michael Haag, Splunk
- ID: bd5c311e-a6ea-48ae-a289-19a3398e3648
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 7 8 | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(Processes.process) as process values(Processes.parent_process) as parent_process from datamodel=Endpoint.Processes by Processes.dest Processes.parent_process_name Processes.user Processes.process_name Processes.process | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `drop_dm_object_name(Processes)` | lookup windows_protocol_handlers handler AS process OUTPUT handler ishandler | where ishandler="TRUE" | `windows_identify_protocol_handlers_filter`
The SPL above uses the following Macros:
windows_identify_protocol_handlers_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
The SPL above uses the following Lookups:
List of fields required to use this analytic.
How To Implement
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
False positives will be found. https and http is a URL Protocol handler that will trigger this analytic. Tune based on process or command-line.
Associated Analytic Story
|6.0||30||20||An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ utilizing a protocol handler.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 2