ID | Technique | Tactic |
---|---|---|
T1003.002 | Security Account Manager | Credential Access |
T1003 | OS Credential Dumping | Credential Access |
Detection: Excel Spawning Windows Script Host
Description
The following analytic identifies instances where Microsoft Excel spawns Windows Script Host processes (cscript.exe
or wscript.exe
). This behavior is detected using Endpoint Detection and Response (EDR) telemetry, focusing on process creation events where the parent process is excel.exe
. This activity is significant because it is uncommon and often associated with malicious actions, such as spearphishing attacks. If confirmed malicious, this could allow an attacker to execute scripts, potentially leading to code execution, data exfiltration, or further system compromise. Immediate investigation and mitigation are recommended.
Search
1
2| tstats `security_content_summariesonly` count values(Processes.process) min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="excel.exe" Processes.process_name IN ("cscript.exe", "wscript.exe") by Processes.parent_process Processes.parent_process_name Processes.process_name Processes.user Processes.dest
3| `drop_dm_object_name("Processes")`
4| `security_content_ctime(firstTime)`
5|`security_content_ctime(lastTime)`
6| `excel_spawning_windows_script_host_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | 'crowdstrike:events:sensor' |
'crowdstrike' |
N/A |
Macros Used
Name | Value |
---|---|
security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
excel_spawning_windows_script_host_filter | search * |
excel_spawning_windows_script_host_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
Default Configuration
This detection is configured by default in Splunk Enterprise Security to run with the following settings:
Setting | Value |
---|---|
Disabled | true |
Cron Schedule | 0 * * * * |
Earliest Time | -70m@m |
Latest Time | -10m@m |
Schedule Window | auto |
Creates Notable | Yes |
Rule Title | %name% |
Rule Description | %description% |
Notable Event Fields | user, dest |
Creates Risk Event | True |
Implementation
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 should be limited, but if any are present, filter as needed. In some instances, cscript.exe
is used for legitimate business practices.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$, indicating potential suspicious macro execution. | 80 | 80 | 100 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
xmlwineventlog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
xmlwineventlog |
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
Source: GitHub | Version: 4