Detection: WMI Temporary Event Subscription

EXPERIMENTAL DETECTION

This detection status is set to experimental. The Splunk Threat Research team has not yet fully tested, simulated, or built comprehensive datasets for this detection. As such, this analytic is not officially supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-08-15 ID: 38cbd42c-1098-41bb-99cf-9d6d2b296d83 Author: Rico Valdez, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of WMI temporary event subscriptions. It leverages Windows Event Logs, specifically EventCode 5860, to identify these activities. This detection is significant because attackers often use WMI to execute commands, gather information, or maintain persistence within a compromised system. If confirmed malicious, this activity could allow an attacker to execute arbitrary code, escalate privileges, or persist in the environment. Analysts should review the specific WMI queries and assess their intent, considering potential false positives from legitimate administrative tasks.

1`wmi` EventCode=5860 Temporary 
2| rex field=Message "NotificationQuery =\s+(?<query>[^;
3|^$]+)" 
4| search query!="SELECT * FROM Win32_ProcessStartTrace WHERE ProcessName = 'wsmprovhost.exe'" AND query!="SELECT * FROM __InstanceOperationEvent WHERE TargetInstance ISA 'AntiVirusProduct' OR TargetInstance ISA 'FirewallProduct' OR TargetInstance ISA 'AntiSpywareProduct'" 
5| stats count min(_time) as firstTime max(_time) as lastTime by ComputerName, query  
6| `security_content_ctime(firstTime)`
7| `security_content_ctime(lastTime)` 
8| `wmi_temporary_event_subscription_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
wmi_temporary_event_subscription_filter search *
wmi_temporary_event_subscription_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1047 Windows Management Instrumentation Execution
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT29
APT32
APT41
Blue Mockingbird
Chimera
Cinnamon Tempest
Deep Panda
Earth Lusca
FIN13
FIN6
FIN7
FIN8
GALLIUM
Gamaredon Group
Indrik Spider
Lazarus Group
Leviathan
Magic Hound
MuddyWater
Mustang Panda
Naikon
OilRig
Sandworm Team
Stealth Falcon
TA2541
Threat Group-3390
ToddyCat
Volt Typhoon
Windshift
Wizard Spider
menuPass

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
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

To successfully implement this search, you must be ingesting the Windows WMI activity logs. This can be done by adding a stanza to inputs.conf on the system generating logs with a title of [WinEventLog://Microsoft-Windows-WMI-Activity/Operational].

Known False Positives

Some software may create WMI temporary event subscriptions for various purposes. The included search contains an exception for two of these that occur by default on Windows 10 systems. You may need to modify the search to create exceptions for other legitimate events.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
tbd 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit ❌ Failing N/A N/A N/A
Integration ❌ Failing N/A N/A N/A

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: 3