splunk-security_content/docs/_posts/2021-07-26-suspicious_rundll32_plugininit.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Suspicious Rundll32 PluginInit	Signed Binary Proxy Execution, Rundll32	Endpoint	2021-07-26	true		Signed Binary Proxy Execution Defense Evasion Rundll32 Defense Evasion Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This search is to detect a suspicious rundll32.exe process with plugininit parameter. This technique is commonly seen in IceID malware to execute its initial dll stager to download another payload to the compromised machine.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-07-26
• Author: Teoderick Contreras, Splunk
• ID: 92d51712-ee29-11eb-b1ae-acde48001122

ATT&CK

ID	Technique	Tactic
T1218	Signed Binary Proxy Execution	Defense Evasion

| T1218.011 | Rundll32 | Defense Evasion |

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_rundll32` Processes.process=*PluginInit* by  Processes.process_name Processes.process Processes.parent_process_name Processes.original_file_name Processes.parent_process Processes.process_id Processes.parent_process_id Processes.dest Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `suspicious_rundll32_plugininit_filter`

Associated Analytic Story

• IcedID

How To Implement

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Required field

• _time
• Processes.dest
• Processes.user
• Processes.parent_process_name
• Processes.parent_process
• Processes.original_file_name
• Processes.process_name
• Processes.process
• Processes.process_id
• Processes.parent_process_path
• Processes.process_path
• Processes.parent_process_id

Kill Chain Phase

• Exploitation

Known False Positives

third party application may used this dll export name to execute function.

RBA

Risk Score	Impact	Confidence	Message
42.0	60	70	rundll32 process process_name with commandline process in host dest

Reference

• https://threatpost.com/icedid-banking-trojan-surges-emotet/165314/

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/icedid/inf_icedid/windows-sysmon.log

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