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Description

This analytic looks for suspicious file creation on init system directories for automatic execution of script or file upon boot up. This technique is commonly abuse by adversaries, malware author and red teamer to persist on the targeted or compromised host. This behavior can be executed or use by an administrator or network operator to add script files or binary files as part of a task or automation. filter is needed.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-12-20
  • Author: Teoderick Contreras, Splunk
  • ID: 97d9cfb2-61ad-11ec-bb2d-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1037.004 RC Scripts Persistence, Privilege Escalation
T1037 Boot or Logon Initialization Scripts Persistence, Privilege Escalation
Kill Chain Phase
  • Installation
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_path IN ("*/etc/init.d/*", "*/etc/rc.d/*", "*/sbin/init.d/*", "*/etc/rc.local*") by Filesystem.dest Filesystem.file_name Filesystem.process_guid Filesystem.file_path 
| `drop_dm_object_name(Filesystem)` 
| `security_content_ctime(lastTime)` 
| `security_content_ctime(firstTime)` 
| `linux_file_creation_in_init_boot_directory_filter`

Macros

The SPL above uses the following Macros:

:information_source: linux_file_creation_in_init_boot_directory_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Filesystem.dest
  • Filesystem.file_create_time
  • Filesystem.file_name
  • Filesystem.process_guid
  • Filesystem.file_path

How To Implement

To successfully implement this search, you need to be ingesting logs with the file name, file path, and process_guid 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 create file in this folders for automation purposes. Please update the filter macros to remove false positives.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
49.0 70 70 A file $file_name$ is created in $file_path$ on $dest$

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

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

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