Recent malware research shows that there is an increase in malware that is using direct system calls to evade user-mode API hooks used by security products. This tool demonstrates the use of direct System Calls and API unhooking and combine these techniques in a proof of concept code which can be used to create a LSASS memory dump using Cobalt Strike, while not touching disk and evading AV/EDR monitored user-mode API calls.
More info about the used techniques can be found on the following Blog: https://outflank.nl/blog/2019/06/19/red-team-tactics-combining-direct-system-calls-and-srdi-to-bypass-av-edr/
Two versions of the code are included:
An executable and a DLL version of the code. The DLL version can be run as follows:
rundll32.exe C:\Dumpert\Outflank-Dumpert.dll,Dump
Also, an sRDI version of the code is provided, including a Cobalt Strike agressor script. This script uses shinject to inject the sRDI shellcode version of the dumpert DLL into the current process. Then it waits a few seconds for the lsass minidump to finish and finally downloads the minidump file from the victim host.
Compile instructions:
This project is written in C and assembly.
You can use Visual Studio to compile it from source.
The sRDI code can be found here: https://github.com/monoxgas/sRDI