Detection: Msmpeng Application DLL Side Loading

Updated Date: 2024-05-16 ID: 8bb3f280-dd9b-11eb-84d5-acde48001122 Author: Teoderick Contreras, Splunk, Sanjay Govind Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the suspicious creation of msmpeng.exe or mpsvc.dll in non-default Windows Defender folders. It leverages the Endpoint.Filesystem datamodel to identify instances where these files are created outside their expected directories. This activity is significant because it is associated with the REvil ransomware, which uses DLL side-loading to execute malicious payloads. If confirmed malicious, this could lead to ransomware deployment, resulting in data encryption, system compromise, and potential data loss or extortion.

1
2|tstats `security_content_summariesonly` values(Filesystem.file_path) as file_path count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where (Filesystem.file_name = "msmpeng.exe" OR Filesystem.file_name = "mpsvc.dll")  AND NOT (Filesystem.file_path IN ("*\\Program Files\\windows defender\\*","*\\WinSxS\\*defender-service*","*\\WinSxS\\Temp\\*defender-service*")) by Filesystem.file_create_time Filesystem.process_id  Filesystem.file_name Filesystem.user Filesystem.dest 
3| `drop_dm_object_name(Filesystem)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `msmpeng_application_dll_side_loading_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($field$)
msmpeng_application_dll_side_loading_filter search *
msmpeng_application_dll_side_loading_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
T1574.002 DLL Side-Loading Defense Evasion
T1574 Hijack Execution Flow Persistence
KillChainPhase.EXPLOITAITON
KillChainPhase.INSTALLATION
NistCategory.DE_CM
Cis18Value.CIS_10
APT19
APT3
APT32
APT41
BRONZE BUTLER
BlackTech
Chimera
Cinnamon Tempest
Earth Lusca
FIN13
GALLIUM
Higaisa
Lazarus Group
LuminousMoth
MuddyWater
Mustang Panda
Naikon
Patchwork
SideCopy
Sidewinder
Threat Group-3390
Tropic Trooper
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 need to be ingesting information on process that include the name of the Filesystem responsible for the changes from your endpoints into the Endpoint datamodel in the Filesystem node.

Known False Positives

quite minimal false positive expected.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Suspicious creation of msmpeng.exe or mpsvc.dll in non default windows defender folder on host - $dest$ 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.

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