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                        NimlineWhispers3
                    Editor: @klezVirus 2022
                    Original: @ajpc500 2021

NimlineWhispers3

As with the original NimlineWhispers2, this project parses the SysWhispers header file output to include function return types and arguments in the outputted inline assembly. Everything is then output into a single Nim file including an emit block with the SysWhispers3 methods, plus the defined functions.

NOTE: NimlineWhispers 1 can be found here. NOTE: NimlineWhispers 2 can be found here.

How do I set this up?

Clone this repository including the SysWhispers3 sub module.
- git clone --recurse-submodules https://github.com/klezVirus/NimlineWhispers3.git
Update which functions you required in functions.txt.
Run python3 NimlineWhispers3.py (additional flags listed below) to generate the inline assembly (syscalls.nim) file - example in the repo.
Add include syscalls to your Nim project.

An example of integrating NimlineWhispers[2-3] output with your project can be seen in this repo.

Randomised Function Names (same functionality as NW1)

To evade detection based on the presence of function names in our Nim executables (as outlined in @ShitSecure's blog here), NimlineWhispers2 can be run with a --randomise flag, as follows:

python3 .\NimlineWhispers2.py --randomise --nobanner
[i] Function filter file "functions.txt" contains 6 functions.

[i] Using SysWhispers2 to generate asm stubs...
Complete! Files written to:
        nimlinewhispers.h
        nimlinewhispers.c
        nimlinewhispersstubs.asm

[i] Found return types for 6 functions.

[i] Producing randomised function mapping...
        NtResumeThread -> vWhUCQWffAEdMboE
        NtAllocateVirtualMemory -> SIitcDuyPGMirHPr
        NtClose -> uWZzTmdnlNmvteiL
        NtCreateThreadEx -> PDoWbNOwYbDDAcmW
        NtOpenProcess -> vWfwKlChxKZOutiX
        NtWriteVirtualMemory -> wItyVDPJWcFUqTNK

[+] Success! Outputted to syscalls.nim

For ease of integration, the mapping shown in the command-line is added as a comment in the outputted syscalls.nim file (just above the functions and below the SW2 methods). As below (including the first function to demonstrate the output):

...

# NtResumeThread -> vWhUCQWffAEdMboE
# NtAllocateVirtualMemory -> SIitcDuyPGMirHPr
# NtClose -> uWZzTmdnlNmvteiL
# NtCreateThreadEx -> PDoWbNOwYbDDAcmW
# NtOpenProcess -> vWfwKlChxKZOutiX
# NtWriteVirtualMemory -> wItyVDPJWcFUqTNK

proc vWhUCQWffAEdMboE*(ThreadHandle: HANDLE, PreviousSuspendCount: PULONG): NTSTATUS {.asmNoStackFrame.} =
    asm """
	mov [rsp +8], rcx 
...

Notably your function definitions such as the below will need to be updated with the randomised names too.

EXTERN_C NTSTATUS NtOpenProcess(
	OUT PHANDLE ProcessHandle,
	IN ACCESS_MASK DesiredAccess,
	IN POBJECT_ATTRIBUTES ObjectAttributes,
	IN PCLIENT_ID ClientId OPTIONAL);

Should become:

EXTERN_C NTSTATUS sjGfpzWwEqIMryMW(
	OUT PHANDLE ProcessHandle,
	IN ACCESS_MASK DesiredAccess,
	IN POBJECT_ATTRIBUTES ObjectAttributes,
	IN PCLIENT_ID ClientId OPTIONAL);

syscalls_rand.nim is included as an example output of this randomisation function.

Instructing SysWhispers3

To modify the behaviour of SysWhispers3, pass the arguments to the subparser sw in NimlineWhispers3:

usage: NimlineWhispers3.py sw [-h] [-a {x86,x64,all}] [-c {msvc,mingw,all}] [-m {embedded,egg_hunter,jumper,jumper_randomized}] [--int2eh] [--wow64] [-v] [--sw-debug]
                                                                                                                                                                      
optional arguments:                                                                                                                                                   
  -h, --help            show this help message and exit                                                                                                               
  -a {x86,x64,all}, --arch {x86,x64,all}                                                                                                                              
                        Architecture                                                                                                                                  
  -c {msvc,mingw,all}, --compiler {msvc,mingw,all}                                                                                                                    
                        Compiler                                                                                                                                      
  -m {embedded,egg_hunter,jumper,jumper_randomized}, --method {embedded,egg_hunter,jumper,jumper_randomized}                                                          
                        Syscall recovery method
  --int2eh              Use the old `int 2eh` instruction in place of `syscall`
  --wow64               Add support for WoW64, to run x86 on x64
  -v, --verbose         Enable debug output
  --sw-debug            Enable syscall debug (insert software breakpoint)

So, to use the "jumper" method, as an example, just use the following command line:

python NimlineWhispers3.py sw -m jumper

Limitations

Egg insertion is not yet fully supported (issue with bytes definition)
32-bits is not yet tested, and may cause issues

Credits