Detection: Windows DLL Side-Loading Process Child Of Calc

Updated Date: 2024-05-22 ID: 295ca9ed-e97b-4520-90f7-dfb6469902e1 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic identifies suspicious child processes spawned by calc.exe, indicative of DLL side-loading techniques. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process GUIDs, names, and parent processes. This activity is significant as it is commonly associated with Qakbot malware, which uses calc.exe to load malicious DLLs via regsvr32.exe. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, maintain persistence, and escalate privileges, posing a severe threat to the environment.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.parent_process_name = "calc.exe")  AND Processes.process_name != "win32calc.exe" by Processes.parent_process Processes.process_name Processes.process_id Processes.process_guid Processes.process Processes.user Processes.dest 
3| `drop_dm_object_name("Processes")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_dll_side_loading_process_child_of_calc_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($field$)
windows_dll_side_loading_process_child_of_calc_filter search *
windows_dll_side_loading_process_child_of_calc_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_AE
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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

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

unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
calc.exe has a child process $process_name$ in $dest$ 81 90 90
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: 2