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Description

This search is to detect a suspicious enabling of smb1protocol through “powershell.exe”. This technique was seen in some ransomware (like reddot) where it enable smb share to do the lateral movement and encrypt other files within the compromise network system.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2021-06-22
  • Author: Teoderick Contreras, Splunk
  • ID: afed80b2-d34b-11eb-a952-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1027 Obfuscated Files or Information Defense Evasion
T1027.005 Indicator Removal from Tools Defense Evasion
Kill Chain Phase
  • Exploitation
NIST
CIS20
CVE 
1
2
3
4
5

`powershell` EventCode=4104 Message = "*Enable-WindowsOptionalFeature*" Message = "*SMB1Protocol*" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode Message ComputerName User 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `powershell_enable_smb1protocol_feature_filter`

Macros

The SPL above uses the following Macros:

Note that powershell_enable_smb1protocol_feature_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
  • EventCode
  • Message
  • ComputerName
  • User

How To Implement

To successfully implement this search, you need to be ingesting logs with the powershell logs from your endpoints. make sure you enable needed registry to monitor this event.

Known False Positives

network operator may enable or disable this windows feature.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
25.0 50 50 Powershell Enable SMB1Protocol Feature

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