ThreadlessInject

Threadless Process Injection

From my Bsides Cymru 2023 talk: Needles Without the Thread.

As red teamers, we always find ourselves in a cat and mouse game with the blue team. Many Anti-virus and EDR solutions over the past 10 years have become significantly more advanced at detecting fileless malware activity in a generic way.

Process injection, a technique used for executing code from within the address space of another process is a common method within the offensive operator’s toolbox. Commonly used to mask activity within legitimate processes such as browsers and instant messaging clients already running on the target workstation.

Within the last 2 years, tools such as Sysmon have added new detections and events for process injection along with big improvements in detections within commercial EDR space. With this in mind, a new method of injection was researched that would not fall foul to the traditional methods that are often detected today.

Possible Improvements

• Use more covert allocation and write primitives.
• Use patchless hooking via debugger attachment and hardware breakpoints (https://www.pentestpartners.com/security-blog/patchless-amsi-bypass-using-sharpblock).
• Avoid RWX on hooked function. Hook assembly will need to handle VirtualProtect calls.
• Support any DLL via remote module enumeration.