ID | Technique | Tactic |
---|---|---|
T1036 | Masquerading | Defense Evasion |
T1036.003 | Rename System Utilities | Defense Evasion |
T1218 | System Binary Proxy Execution | Defense Evasion |
T1218.004 | InstallUtil | Defense Evasion |
Detection: Windows DotNet Binary in Non Standard Path
Description
The following analytic detects the execution of native .NET binaries from non-standard directories within the Windows operating system. It leverages Endpoint Detection and Response (EDR) telemetry, comparing process names and original file names against a predefined lookup using the is_net_windows_file_macro
macro. This activity is significant because adversaries may move .NET binaries to unconventional paths to evade detection and execute malicious code. If confirmed malicious, this behavior could allow attackers to execute arbitrary code, escalate privileges, or maintain persistence within the environment, posing a significant security risk.
Search
1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes where NOT (Processes.process_path IN ("*\\Windows\\ADWS\\*","*\\Windows\\SysWOW64*", "*\\Windows\\system32*", "*\\Windows\\NetworkController\\*", "*\\Windows\\SystemApps\\*", "*\\WinSxS\\*", "*\\Windows\\Microsoft.NET\\*")) by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.original_file_name Processes.process_path Processes.process_id Processes.parent_process_id
3| `drop_dm_object_name("Processes")`
4| `security_content_ctime(firstTime)`
5| `security_content_ctime(lastTime)`
6| `is_net_windows_file_macro`
7| `windows_dotnet_binary_in_non_standard_path_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
CrowdStrike ProcessRollup2 | N/A | 'crowdstrike:events:sensor' |
'crowdstrike' |
N/A |
Macros Used
Name | Value |
---|---|
is_net_windows_file_macro | `lookup update=true is_net_windows_file filename as process_name OUTPUT netFile |
windows_dotnet_binary_in_non_standard_path_filter | search * |
windows_dotnet_binary_in_non_standard_path_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
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
False positives may be present and filtering may be required. Certain utilities will run from non-standard paths based on the third-party application in use.
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
An instance of $parent_process_name$ spawning $process_name$ from a non-standard path was identified on endpoint $dest$ by user $user$. | 49 | 70 | 70 |
References
-
https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1036.003/T1036.003.yaml
-
https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md
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: 3