Detection: Linux Change File Owner To Root

Description

The following analytic detects the use of the 'chown' command to change a file owner to 'root' on a Linux system. It leverages Endpoint Detection and Response (EDR) telemetry, specifically monitoring command-line executions and process details. This activity is significant as it may indicate an attempt to escalate privileges by adversaries, malware, or red teamers. If confirmed malicious, this action could allow an attacker to gain root-level access, leading to full control over the compromised host and potential persistence within the environment.

Search

 1
 2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
 3  WHERE (
 4        Processes.process_name = chown
 5        OR
 6        Processes.process = "*chown *"
 7    )
 8    AND Processes.process = "* root *"
 9  BY Processes.action Processes.dest Processes.original_file_name
10     Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
11     Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
12     Processes.process Processes.process_exec Processes.process_guid
13     Processes.process_hash Processes.process_id Processes.process_integrity_level
14     Processes.process_name Processes.process_path Processes.user
15     Processes.user_id Processes.vendor_product
16
17| `drop_dm_object_name(Processes)`
18
19| `security_content_ctime(firstTime)`
20
21| `security_content_ctime(lastTime)`
22
23| `linux_change_file_owner_to_root_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon for Linux EventID 1	Linux	'sysmon:linux'	'Syslog:Linux-Sysmon/Operational'

Macros Used

Annotations

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

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

Administrator or network operator can execute this command. Please update the filter macros to remove false positives.

Associated Analytic Story

• Linux Persistence Techniques

• Linux Privilege Escalation

• Linux Living Off The Land

Intermediate Findings

References

• https://askubuntu.com/questions/617850/changing-from-user-to-superuser

• https://unix.stackexchange.com/questions/101073/how-to-change-permissions-from-root-user-to-all-users

Detection Testing

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: 11