The following analytic utilizes PowerShell Script Block Logging (EventCode=4104) to identify the execution of PowerShell with arguments utilized to start a process on a remote endpoint by abusing the DCOM protocol. Specifically, this search looks for the abuse of ShellExecute and ExecuteShellCommand. Red Teams and adversaries alike may abuse DCOM for lateral movement and remote code execution.
- Type: TTP
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2022-03-22
- Author: Mauricio Velazco, Splunk
- ID: fa1c3040-4680-11ec-a618-3e22fbd008af
Kill Chain Phase
1 2 3 4 5 `powershell` EventCode=4104 (ScriptBlockText="*Document.Application.ShellExecute*" OR ScriptBlockText="*Document.ActiveView.ExecuteShellCommand*") | stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer user_id | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `remote_process_instantiation_via_dcom_and_powershell_script_block_filter`
The SPL above uses the following Macros:
remote_process_instantiation_via_dcom_and_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 instructions can be found https://docs.splunk.com/Documentation/UBA/184.108.40.206/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Known False Positives
Administrators may leverage DCOM to start a process on remote systems, but this activity is usually limited to a small set of hosts or users.
Associated Analytic Story
|63.0||90||70||A process was started on a remote endpoint from $ComputerName by abusing WMI using PowerShell.exe|
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