Try in Splunk Security Cloud

Description

This analytic is to detect a possible attempt to dump or access the content of /etc/passwd and /etc/shadow to enable offline credential cracking. "etc/passwd" store user information within linux OS while "etc/shadow" contain the user passwords hash. Adversaries and threat actors may attempt to access this to gain persistence and/or privilege escalation. This anomaly detection can be a good indicator of possible credential dumping technique but it might catch some normal administrator automation scripts or during credential auditing. In this scenario filter is needed.

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2022-01-10
  • Author: Teoderick Contreras, Splunk
  • ID: 16107e0e-71fc-11ec-b862-acde48001122

ATT&CK

ID Technique Tactic
T1003.008 /etc/passwd and /etc/shadow Credential Access
T1003 OS Credential Dumping Credential Access

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name IN("cat", "nano*","vim*", "vi*")  AND Processes.process IN("*/etc/shadow*", "*/etc/passwd*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `linux_possible_access_to_credential_files_filter`

Associated Analytic Story

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.

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_id

Kill Chain Phase

  • Privilege Escalation

Known False Positives

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

RBA

Risk Score Impact Confidence Message
25.0 50 50 A commandline $process$ executed on $dest$

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

source | version: 1