WMI Permanent Event Subscription - Sysmon
Description
The following analytic identifies the creation of WMI permanent event subscriptions, which can be used to establish persistence or perform privilege escalation. It leverages Sysmon data, specifically EventCodes 19, 20, and 21, to detect the creation of WMI EventFilters, EventConsumers, and FilterToConsumerBindings. This activity is significant as it may indicate an attacker setting up mechanisms to execute code with elevated SYSTEM privileges when specific events occur. If confirmed malicious, this could allow the attacker to maintain persistence, escalate privileges, and execute arbitrary code, posing a severe threat to the environment.
- Type: TTP
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2024-05-20
- Author: Rico Valdez, Michael Haag, Splunk
- ID: ad05aae6-3b2a-4f73-af97-57bd26cee3b9
Annotations
ATT&CK
Kill Chain Phase
- Exploitation
- Installation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
1
2
3
4
`sysmon` EventCode=21
| rename host as dest
| table _time, dest, user, Operation, EventType, Query, Consumer, Filter
| `wmi_permanent_event_subscription___sysmon_filter`
Macros
The SPL above uses the following Macros:
wmi_permanent_event_subscription_-_sysmon_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _time
- EventCode
- host
- user
- Operation
- EventType
- Query
- Consumer
- Filter
How To Implement
To successfully implement this search, you must be collecting Sysmon data using Sysmon version 6.1 or greater and have Sysmon configured to generate alerts for WMI activity (eventID= 19, 20, 21). In addition, you must have at least version 6.0.4 of the Sysmon TA installed to properly parse the fields.
Known False Positives
Although unlikely, administrators may use event subscriptions for legitimate purposes.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
30.0 | 30 | 100 | WMI Permanent Event Subscription detected on $dest$ by $user$ |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1546.003/T1546.003.md
- https://www.eideon.com/2018-03-02-THL03-WMIBackdoors/
- https://github.com/trustedsec/SysmonCommunityGuide/blob/master/chapters/WMI-events.md
- https://in.security/2019/04/03/an-intro-into-abusing-and-identifying-wmi-event-subscriptions-for-persistence/
Test Dataset
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 | version: 3