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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 syscallsto 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
- apjc500 for NimlineWhispers2 which practically already implemented all the logic of this tool.
- Cas van Cooten and yamakadi for posing and then answering how SW2 output could be used in Nim projects, which I've simply codified😁
- This tool uses SysWhispers3 to generate syscall stubs which are then processed for Nim.
- SysWhispers3 is based on SysWhispers2, so huge props to @Jackson_T for
SysWhispers2. - FalconForce's SysWhispers2BOF from which I borrowed several helper functions.
- All people credited for SysWhispers and SysWhispers2
- @Outflank and @_DaWouw for InlineWhispers
- @byt3bl33d3r for his incredibly informative OffensiveNim repository
- S3cur3Th1sSh1t for giving me a reason to work on this project.