LOLSpoof – A Clever Technique To Evade Command Line Detection And Maintain OPSEC

LOLSpoof is a an interactive shell program that automatically spoof the command line arguments of the spawned process. Just call your incriminate-looking command line LOLBin (e.g. powershell -w hidden -enc ZwBlAHQALQBwAHIAbwBjAGUA....) and LOLSpoof will ensure that the process creation telemetry appears legitimate and clear.

Why

Process command line is a very monitored telemetry, being thoroughly inspected by AV/EDRs, SOC analysts or threat hunters.

How

1. Prepares the spoofed command line out of the real one: lolbin.exe " " * sizeof(real arguments)
2. Spawns that suspended LOLBin with the spoofed command line
3. Gets the remote PEB address
4. Gets the address of RTL_USER_PROCESS_PARAMETERS struct
5. Gets the address of the command line unicode buffer
6. Overrides the fake command line with the real one
7. Resumes the main thread

Opsec Considerations

Although this simple technique helps to bypass command line detection, it may introduce other suspicious telemetry:

1. Creation of suspended process
2. The new process has trailing spaces (but it’s really easy to make it a repeated character or even random data instead)
3. Write to the spawned process with WriteProcessMemory