linux-bof-loader

A standalone C implementation of a "Beacon Object File" (BOF) loader designed for Linux x86-64 environments.

It simulates the "Beacon Object File" (BOF) execution model found in tools like Cobalt Strike or Sliver but adapted for Linux ELF binaries. It includes a custom argument packing protocol that allows you to pass integers, shorts, strings, and binary blobs from the command line directly to your C payload.

Features

• ELF Loading: Parses and loads x64 ELF relocatable objects (ET_REL) into memory.
• Dynamic Relocation: Handles standard x64 relocations (R_X86_64_64, PC32, PLT32) to ensure code executes correctly at arbitrary memory addresses.
• Symbol Resolution: Automatically resolves external function calls (like malloc, snprintf) using the host's standard library via dlsym.
• Argument Packing: Includes a built-in CLI argument packer that serializes arguments into a binary format compatible with the included payload parser.

Building

You will need gcc to compile both the loader and the payload.

make

Usage

Run the loader and pass arguments in the format type:value.

The example payload (example.c) expects arguments in this specific order:

1. Integer (ID)
2. Short (Age)
3. String (Name)

Supported Argument Types

Prefix	Type	Description	Example
int:	4-byte Integer	standard integer	int:1234
short:	2-byte Short	short integer	short:42
str:	String	null-terminated string	str:Hello
bin:	Binary	hex-encoded byte string	bin:aabbcc

Example Run

./loader example.o go int:1337 short:25 str:Alice

Expected Output:

Invoking go at 0x7f...
Result: [1337] Hello, Alice (25)!