ID | Technique | Tactic |
---|---|---|
T1055 | Process Injection | Defense Evasion |
Detection: Rundll32 Create Remote Thread To A Process
Description
The following analytic detects the creation of a remote thread by rundll32.exe into another process. It leverages Sysmon EventCode 8 logs, specifically monitoring SourceImage and TargetImage fields. This activity is significant as it is a common technique used by malware, such as IcedID, to execute malicious code within legitimate processes, aiding in defense evasion and data theft. If confirmed malicious, this behavior could allow an attacker to execute arbitrary code, escalate privileges, and exfiltrate sensitive information from the compromised host.
Search
1`sysmon` EventCode=8 SourceImage = "*\\rundll32.exe" TargetImage = "*.exe"
2| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage TargetImage TargetProcessId SourceProcessId StartAddress EventCode dest
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `rundll32_create_remote_thread_to_a_process_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Sysmon EventID 8 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' |
N/A |
Macros Used
Name | Value |
---|---|
security_content_ctime | convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$) |
rundll32_create_remote_thread_to_a_process_filter | search * |
rundll32_create_remote_thread_to_a_process_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
Implementation
To successfully implement this search, you need to be ingesting logs with the SourceImage, TargetImage, and EventCode executions from your endpoints related to create remote thread or injecting codes. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
Known False Positives
unknown
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
rundl32 process $SourceImage$ create a remote thread to process $TargetImage$ in host $dest$ | 56 | 70 | 80 |
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