The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of the
Get-NetTcpconnection commandlet. This commandlet is used to return a listing of network connections on a compromised system. Red Teams and adversaries alike may use this commandlet for situational awareness and Active Directory Discovery.
- Type: Hunting
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-04-02
- Author: Mauricio Velazco, Splunk
- ID: 091712ff-b02a-4d43-82ed-34765515d95d
Kill Chain Phase
- CIS 10
1 2 3 4 `powershell` EventCode=4104 (ScriptBlockText = "*Get-NetTcpconnection*") | stats count min(_time) as firstTime max(_time) as lastTime by Opcode Computer UserID EventCode ScriptBlockText | `security_content_ctime(firstTime)` | `getnettcpconnection_with_powershell_script_block_filter`
The SPL above uses the following Macros:
getnettcpconnection_with_powershell_script_block_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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/220.127.116.11/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Known False Positives
Administrators or power users may use this PowerShell commandlet for troubleshooting.
Associated Analytic Story
|15.0||30||50||Network Connection discovery on $Computer$ by $user$|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 2