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Description

The following analytic identifies suspicious PowerShell script execution via EventCode 4104 performing checks to identify anti-virus products installed on the endpoint. This technique is commonly found in malware and APT events where the adversary will map all running security applications or services. During triage, review parallel processes within the same timeframe. Review the full script block to identify other related artifacts.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2022-03-22
  • Author: Teoderick Contreras, Splunk
  • ID: 28077620-c9f6-11eb-8785-acde48001122

Annotations

ATT&CK
ID Technique Tactic
T1592 Gather Victim Host Information Reconnaissance
Kill Chain Phase
  • Reconnaissance
NIST
CIS20
CVE
1
2
3
4
5
`powershell` EventCode=4104 (ScriptBlockText = "*SELECT*" OR ScriptBlockText = "*WMIC*") AND (ScriptBlockText = "*AntiVirusProduct*" OR ScriptBlockText = "*AntiSpywareProduct*") 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `recon_avproduct_through_pwh_or_wmi_filter`

Macros

The SPL above uses the following Macros:

Note that recon_avproduct_through_pwh_or_wmi_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 analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.

Known False Positives

network administrator may used this command for checking purposes

Associated Analytic story

RBA

Risk Score Impact Confidence Message
56.0 70 80 A suspicious powershell script contains AV recon command in $Message$ with EventCode $EventCode$ in host $ComputerName$

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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