Suspicious script in the command line
You believe a script run on the command line caused a user’s machine to become infected with malware. You want to see the entire script to be able to analyze it further.
Required data
Procedure
This sample search uses Sysmon data. You can replace this source with any other system log data used in your organization.
Run the following search.You can optimize it by specifying an index and adjusting the time range.
host=<hostname> sourcetype=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational *.exe CommandLine=* EventCode=1 |table CommandLine length
Search explanation
The table provides an explanation of what each part of this search achieves. You can adjust this query based on the specifics of your environment.
| Splunk Search | Explanation |
|---|---|
|
host=<hostname> |
Restrict your search to the known infected host. |
|
sourcetype=XmlWinEventLog:Microsoft-Windows-Sysmon/Operational |
Search only Windows Sysmon operational logs. Sysmon can create many types of logs. As your organization scales, you’ll want to be familiar with the kinds of events Sysmon captures. SwiftOnSecurity offers a popular XML configuration file. |
|
*.exe |
Search for process execution. |
|
CommandLine=* |
Search for command line processes. |
|
EventCode=1 |
Search for process creation events in Sysmon data. |
|
|table CommandLine |
Display the CommandLine field results of the search in a table. |
Next steps
The CommandLine results provide the context of the process execution. After you identify a suspicious script, review it for content that you can create alarms from to prevent or detect future, similar attacks.
Finally, you might be interested in other processes associated with the Investigating a ransomware attack use case.