TA0005 · DEFENSE EVASION
System Script Proxy Execution
Adversaries may use trusted scripts, often signed with certificates, to proxy the execution of malicious files.
Detect it with
Monitor script processes, such as cscript, and command-line parameters for scripts like PubPrn.vbs that may be used to proxy execution of malicious files.
Why it matters on shift
System Script Proxy Execution is one of the concrete ways adversaries achieve defense evasion. Recognising it in telemetry lets you name the technique in your ticket and pivot to what came before and after.
What to look for next
After defense evasion, the next tactic is usually Credential Access. Search your telemetry for the transition before closing the ticket.
2 sub-techniques
How it shows up in practice
- T1216.001
PubPrn
Adversaries may use PubPrn to proxy execution of malicious remote files. PubPrn.vbs is a Visual Basic script that publishes a printer to Active Directory Domain Services.
- T1216.002
SyncAppvPublishingServer
Adversaries may abuse SyncAppvPublishingServer.vbs to proxy execution of malicious PowerShell commands. SyncAppvPublishingServer.vbs is a Visual Basic script associated with how Windows virtualizes applications (Microsoft Application Virtualization, or App-V).
Kill-chain context