Sliver C2 Implant Activity Pattern [splunk-sysmon]

Adversaries may abuse command and script interpreters to execute commands, scripts, or binaries. These interfaces and languages provide ways of interacting with computer systems and are a common feature across many different platforms. Most systems come with some built-in command-line interface and scripting capabilities, for example, macOS and Linux distributions include some flavor of Unix Shell while Windows installations include the Windows Command Shell and PowerShell. This use case detects process activity patterns related to Sliver C2 framework implants when spawning PowerShell.