This analytic looks for commands to create user accounts on the linux platform. This technique is commonly abuse by adversaries, malware author and red teamers to persist on the targeted or compromised host by creating new user with an elevated privilege. This Hunting query may catch normal creation of user by administrator so filter is needed.
- Type: Hunting
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-12-21
- Author: Teoderick Contreras, Splunk
- ID: 51fbcaf2-6259-11ec-b0f3-acde48001122
Kill Chain Phase
- CIS 3
- CIS 5
- CIS 16
1 2 3 4 5 6 | tstats `security_content_summariesonly` count from datamodel=Endpoint.Processes where Processes.process_name IN ("useradd", "adduser") OR Processes.process IN ("*useradd *", "*adduser *") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id Processes.process_guid | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_add_user_account_filter`
The SPL above uses the following Macros:
linux_add_user_account_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
How To Implement
To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you can use the Add-on for Linux Sysmon from Splunkbase.
Known False Positives
Administrator or network operator can execute this command. Please update the filter macros to remove false positives.
Associated Analytic Story
|25.0||50||50||A commandline $process$ that may create user account on $dest$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1