TA0003 · PERSISTENCE
IIS Components
Adversaries may install malicious components that run on Internet Information Services (IIS) web servers to establish persistence. IIS provides several mechanisms to extend the functionality of the web servers.
Detect it with
Monitor for creation and/or modification of files (especially DLLs on webservers) that could be abused as malicious ISAPI extensions/filters or IIS modules. Changes to %windir%\system32\inetsrv\config\applicationhost.config could indicate an IIS module installation.
Why it matters on shift
IIS Components is one of the concrete ways adversaries achieve persistence. 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 persistence, the next tactic is usually Privilege Escalation. Search your telemetry for the transition before closing the ticket.
Kill-chain context