/Shhhloader

Syscall Shellcode Loader (Work in Progress)

Primary LanguagePythonGNU General Public License v3.0GPL-3.0

Shhhloader

Shhhloader is a work in progress shellcode loader. It takes raw shellcode as input and compiles a C++ stub that does a bunch of different things to try and bypass AV/EDR. The included python builder will work on any Linux system that has Mingw-w64 installed.

4/13/23 EDIT: SysWhispers3 support has been added. Thanks to @KlezVirus for his work on the original project. SysWhispers2 syscalls have also been fixed and are supported again. In addition, both SW2 & SW3 should now work with all shellcode injection techniques. Stay tuned for the addition of more syscall execution methods soon. :)

4/4/23 EDIT: ThreadlessInject has been added to Shhhloader! Thanks to @_EthicalChaos_ for their initial project, and 0xLegacyy for their BOF version which was adapted for use here. In addition, unhooking NTDLL via KnownDLLs has been added thanks to @D1rkMtr. Finally, SysWhispers2 has been deprecated in this version for various reasons. I am currently working on adding a HWBP syscall option which should be pushed later this month. See the "Planned Updates" section below for more information regarding future planned features.

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┻┳| •.•)  - Shhhhh, AV might hear us!
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usage: Shhhloader.py [-h] [-p explorer.exe] [-m QueueUserAPC] [-u] [-w] [-nr] [-ns] [-np] [-l] [-v] [-sc GetSyscallStub] [-d] [-dp apphelp.dll]
                     [-s domain] [-sa testlab.local] [-o a.exe] [-cp] [-td ntdll.dll] [-ef NtClose]
                     file

ICYGUIDER'S CUSTOM SYSCALL SHELLCODE LOADER

positional arguments:
  file                  File containing raw shellcode

options:
  -h, --help            show this help message and exit
  -p explorer.exe, --process explorer.exe
                        Process to inject into (Default: explorer.exe)
  -m QueueUserAPC, --method QueueUserAPC
                        Method for shellcode execution (Options: ThreadlessInject, ModuleStomping, QueueUserAPC, ProcessHollow, EnumDisplayMonitors,
                        RemoteThreadContext, RemoteThreadSuspended, CurrentThread) (Default: QueueUserAPC)
  -u, --unhook          Unhook NTDLL in current process
  -w, --word-encode     Save shellcode in stub as array of English words
  -nr, --no-randomize   Disable syscall name randomization
  -ns, --no-sandbox     Disable sandbox checks
  -np, --no-ppid-spoof  Disable PPID spoofing
  -l, --llvm-obfuscator
                        Use Obfuscator-LLVM to compile stub
  -v, --verbose         Enable debugging messages upon execution
  -sc GetSyscallStub, --syscall GetSyscallStub
                        Syscall execution method (Options: SysWhispers2, SysWhispers3, GetSyscallStub, None) (Default: GetSyscallStub)
  -d, --dll             Generate a DLL instead of EXE
  -dp apphelp.dll, --dll-proxy apphelp.dll
                        Create Proxy DLL using supplied legitimate DLL (File must exist in current dir)
  -s domain, --sandbox domain
                        Sandbox evasion technique (Options: sleep, domain, hostname, username, dll) (Default: sleep)
  -sa testlab.local, --sandbox-arg testlab.local
                        Argument for sandbox evasion technique (Ex: WIN10CO-DESKTOP, testlab.local)
  -o a.exe, --outfile a.exe
                        Name of compiled file

ThreadlessInject:
  -cp, --create-process
                        Create process instead of injecting into existing one
  -td ntdll.dll, --target-dll ntdll.dll
                        Target DLL containing export function to overwrite
  -ef NtClose, --export-function NtClose
                        Export function to overwrite

Features:

  • 8 Different Shellcode Execution Methods (ThreadlessInject, ModuleStomping, QueueUserAPC, ProcessHollow, EnumDisplayMonitors, RemoteThreadContext, RemoteThreadSuspended, CurrentThread)
  • PPID Spoofing
  • Block 3rd Party DLLs
  • Unhook NTDLL via KnownDLLs
  • SysWhispers2, SysWhispers3, & GetSyscallStub
  • API Hashing for SW2 & SW3
  • Compile-Time String Encryption
  • Obfuscator-LLVM (OLLVM) Support
  • Automatic DLL Proxy Generation
  • Syscall Name Randomization
  • Store Shellcode as English Word Array
  • XOR Encoding with Dynamic Key Generation
  • Sandbox Evasion via Loaded DLL, Domain, User, Hostname, and System Enumeration

See below for a PoC video of the ThreadlessInject method being used to inject a Havoc beacon into IE without generating any alerts and minimal events in Microsoft Defender for Endpoint (MDE) EDR (Recorded 4/3/2023):

Shhhloader_ThreadlessInject_vs_Microsoft_Defender_for_Endpoint.mp4

See below video demonstrating the Module Stomping injection technique executed via DLL Proxying (Recorded 8/9/2022):

See Video
Shhhloader_Module_Stomping_DLL_Proxying.mp4

Shhhloader also now contains an aggressor script for use with Cobalt Strike! Simply import the Shhhloader.cna file with the script manager to use. All files used/created by the aggressor script should be located in your locally cloned Shhhloader repo.

See Screenshot Aggressor Script Screenshot

Known Issues:

  • The ThreadlessInject shellcode execution method must currently inject into a non-suspended process. This is done automatically for you if the "-cp" option is supplied. I hope to figure out a way to get it working with suspended processes soon.
  • The Cobalt Strike aggressor script has not been updated. It is probably broken unless used with older Shhhloader versions. It will be updated & fixed when I have time.
  • Windows Defender will detect most files generated by this tool, so please do not post an issue saying "DETECTED!!!". Play around with the new options and features until you get something that works; they were added for a reason :). Executing the generated file in memory is also a good way to evade these detections.
  • There are a ton of bugs in my code. Please test everything in advance before using for something important, and PLEASE provide as much information as possible when opening an issue. (THANKS!)

Planned Updates:

  • Hardware Breakpoint (HWBP) syscall option
  • Create processess using syscall instead of standard WinAPI function
  • Integrate ThreadlessInject with other shellcode injection techniques (Ex. ModuleStomping)
  • Refactor code to be more modular and readable
  • Fix countless bugs by learning to program better ;)

OPTIONAL: To use the Obfuscator-LLVM flag, you must have it installed on your system alongside wclang. I've found this to be a bit of a pain but you should be able to do it with a little perseverance. Here's a step-by-step that I used to install the llvm-13.x branch of OLLVM on my Kali Linux system:

See Details 
# Clone and Run CMake
git clone -b llvm-13.x https://github.com/heroims/obfuscator.git
mkdir build
cd build
cmake -DCMAKE_BUILD_TYPE=Release -DLLVM_ENABLE_NEW_PASS_MANAGER=OFF ../obfuscator/llvm/

# Configure CMake and Compile OLLVM
export clang_build_dir=$(cd ../; pwd)/obfuscator/clang
sed -i 's/LLVM_TOOL_CLANG_BUILD:BOOL=OFF/LLVM_TOOL_CLANG_BUILD:BOOL=ON/g' CMakeCache.txt
sed -i "s|LLVM_EXTERNAL_CLANG_SOURCE_DIR:PATH=|LLVM_EXTERNAL_CLANG_SOURCE_DIR:PATH=$clang_build_dir|g" CMakeCache.txt
make -j7

# ONCE COMPILED, BACKUP ORIGINAL CLANG BINARIES
mv /usr/bin/clang /usr/bin/clang13.0.1
mv /usr/bin/clang++ /usr/bin/clang++13.0.1

# Then in OLLVM build/bin dir, copy the newly build clang bins
cp bin/clang /usr/bin/clang
cp bin/clang++ /usr/bin/clang++

# Then install wclang
cd ..
git clone https://github.com/tpoechtrager/wclang.git
cd wclang/
cmake -DCMAKE_INSTALL_PREFIX=_prefix_ .
make
make install
export wclang_path=$(pwd)/_prefix_/bin
echo "export PATH=$wclang_path:$PATH" >> ~/.bashrc
export PATH=$wclang_path:$PATH

# Then backup original lib files
cp -R /lib/llvm-13/lib/clang/13.0.1/include/ /lib/llvm-13/lib/clang/13.0.1/include_backup/

# Finally in the OLLVM build/bin/lib/clang/13.0.1/ dir, copy the include folder
cd ../build/lib/clang/13.0.1/
cp -R include/ /lib/llvm-13/lib/clang/13.0.1/

There is probably a better way to do this but this is what worked for me. If you have issues, just keep trying and ensure that you can run x86_64-w64-mingw32-clang++ -v and it contains either "Obfuscator-LLVM" or "heroims" in the output. Unfortunately I do not have the time to assist individuals who may need more help, but you can try reading this issue on my Nimcrypt2 repo where a couple of users figured out how to do it on their systems.

Greetz & Credit: