ID | Technique | Tactic |
---|---|---|
T1218.004 | InstallUtil | Defense Evasion |
T1218 | System Binary Proxy Execution | Defense Evasion |
Detection: Windows InstallUtil Uninstall Option with Network
Description
The following analytic identifies the use of Windows InstallUtil.exe making a remote network connection using the /u
(uninstall) switch. This detection leverages Endpoint Detection and Response (EDR) telemetry, focusing on process and network activity data. This behavior is significant as it may indicate an attempt to download and execute code while bypassing application control mechanisms. If confirmed malicious, this activity could allow an attacker to execute arbitrary code, potentially leading to system compromise, data exfiltration, or further lateral movement within the network.
Search
1
2| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where `process_installutil` Processes.process IN ("*/u*", "*uninstall*") by _time span=1h Processes.user Processes.process_id Processes.process_name Processes.dest Processes.process_path Processes.process Processes.parent_process_name
3| `drop_dm_object_name(Processes)`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| join process_id [
7| tstats `security_content_summariesonly` count FROM datamodel=Network_Traffic.All_Traffic where All_Traffic.dest_port != 0 by All_Traffic.process_id All_Traffic.dest All_Traffic.dest_port
8| `drop_dm_object_name(All_Traffic)`
9| rename dest as C2 ]
10| table _time user dest parent_process_name process_name process_path process process_id dest_port C2
11| `windows_installutil_uninstall_option_with_network_filter`
Data Source
Name | Platform | Sourcetype | Source |
---|---|---|---|
Sysmon EventID 1 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
Sysmon EventID 3 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
Macros Used
Name | Value |
---|---|
process_installutil | (Processes.process_name=installutil.exe OR Processes.original_file_name=InstallUtil.exe) |
windows_installutil_uninstall_option_with_network_filter | search * |
windows_installutil_uninstall_option_with_network_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
Limited false positives should be present as InstallUtil is not typically used to download remote files. Filter as needed based on Developers requirements.
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 $user$ performing an uninstall. | 80 | 80 | 100 |
References
-
https://evi1cg.me/archives/AppLocker_Bypass_Techniques.html#menu_index_12
-
https://github.com/api0cradle/UltimateAppLockerByPassList/blob/master/md/Installutil.exe.md
-
https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md
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