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Description

This analytic looks for the presence of suspicious commandline parameters typically present when using Impacket tools. Impacket is a collection of python classes meant to be used with Microsoft network protocols. There are multiple scripts that leverage impacket libraries like wmiexec.py, smbexec.py, dcomexec.py and atexec.py used to execute commands on remote endpoints. By default, these scripts leverage administrative shares and hardcoded parameters that can be used as a signature to detect its use. Red Teams and adversaries alike may leverage Impackets tools for lateral movement and remote code execution.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
  • Last Updated: 2022-01-18
  • Author: Mauricio Velazco, Splunk
  • ID: 8ce07472-496f-11ec-ab3b-3e22fbd008af

Annotations

ATT&CK
ID Technique Tactic
T1021 Remote Services Lateral Movement
T1021.002 SMB/Windows Admin Shares Lateral Movement
T1021.003 Distributed Component Object Model Lateral Movement
T1047 Windows Management Instrumentation Execution
T1543.003 Windows Service Persistence, Privilege Escalation
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE
1
2
3
4
5
6
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process = "*/c* \\\\127.0.0.1\\*" OR Processes.process= "*/c* 2>&1") 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)` 
| `impacket_lateral_movement_commandline_parameters_filter`

Macros

The SPL above uses the following Macros:

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

Required field

  • _time
  • Processes.dest
  • Processes.user
  • Processes.parent_process_name
  • Processes.parent_process
  • Processes.original_file_name
  • Processes.process_name
  • Processes.process
  • Processes.process_id
  • Processes.parent_process_path
  • Processes.process_path
  • Processes.parent_process_id

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.

Known False Positives

Although uncommon, Administrators may leverage Impackets tools to start a process on remote systems for system administration or automation use cases.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
63.0 90 70 Suspicious command line parameters on $dest may represent a lateral movement attack with Impackets tools

: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

source | version: 2