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woody-woodpacker
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assembly simplified

This commit is contained in:
pbonilla 2024-02-23 14:17:23 +01:00
parent 086bda7642
commit b714716094
6 changed files with 53 additions and 53 deletions
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6
README
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@ -1,5 +1,5 @@
Transform payload code in hexa :
nasm -f elf64 -o print.o print.s && ld -o print print.o && nasm -f bin -o payload print.s && hexdump -v -e '"\\\x\" 1/1 "%02x"' payload
nasm -f elf64 -o print.o print.s && ld -o print print.o && nasm -f bin -o payload print.s && hexdump -v -e '"\\\x\" 1/1 "%02x"' payload
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4
diff.txt
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@ -1,4 +0,0 @@
2c2
< resources/sample64: file format elf64-x86-64
---
> woody: file format elf64-x86-64

4
includes/woody.h
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@ -14,8 +14,8 @@
#include <elf.h>
#include <stdint.h>
#define PAYLOAD "\x50\x57\x56\x52\x53\x31\xc0\x99\xb2\x0a\xff\xc0\x89\xc7\x48\x8d\x35\x0c\x00\x00\x00\x0f\x05\x5b\x5a\x5e\x5f\x58\xe9\xdf\xff\xff\xff\x2e\x2e\x57\x4f\x4f\x44\x59\x2e\x2e\x0a"
#define JUMP "\xe9";//\xdf\xff\xff\xff";
#define PAYLOAD "\x50\x57\x56\x52\x53\xbf\x01\x00\x00\x00\x48\x8d\x35\x16\x00\x00\x00\xba\x0a\x00\x00\x00\xb8\x01\x00\x00\x00\x0f\x05\x5b\x5a\x5e\x5f\x58\xe9\xd9\xff\xff\xff\x2e\x2e\x57\x4f\x4f\x44\x59\x2e\x2e\x0a"
#define JUMP "\xe9"
typedef struct efl_content
{

66
print.s
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@ -1,28 +1,52 @@
; bits 64
; default rel
; global _start
; _start:
; push rax
; push rdi
; push rsi
; push rdx
; push rbx
; xor eax, eax
; cdq
; mov dl, 10
; inc eax
; mov edi, eax
; lea rsi, [rel msg]
; syscall
; pop rbx
; pop rdx
; pop rsi
; pop rdi
; pop rax
; jmp 0x00000000
; msg db "..WOODY..",10
bits 64
default rel
global _start
_start:
push rax
push rdi
push rsi
push rdx
push rbx
xor eax, eax
cdq
mov dl, 10
inc eax
mov edi, eax
lea rsi, [rel msg]
syscall
pop rbx
pop rdx
pop rsi
pop rdi
pop rax
jmp 0x00000000
push rax
push rdi
push rsi
push rdx
push rbx
mov rdi, 1
lea rsi, [rel msg]
mov rdx, 10
mov rax, 1
syscall
pop rbx
pop rdx
pop rsi
pop rdi
pop rax
jmp 0x00000000
msg db "..WOODY..",10

17
shellcode_test.c
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@ -1,17 +0,0 @@
#include <stdio.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/mman.h>
char code[] = "\x31\xc0\x99\xb2\x0a\xff\xc0\x89\xc7\x48\x8d\x35\x12\x00\x00\x00\x0f\x05\xb2\x2a\x31\xc0\xff\xc0\xf6\xe2\x89\xc7\x31\xc0\xb0\x3c\x0f\x05\x2e\x2e\x57\x4f\x4f\x44\x59\x2e\x2e\x0a";
typedef void (*ShellcodeFunc)();
int main() {
ShellcodeFunc func = (ShellcodeFunc)code;
size_t pagesize = 4096; // 4KB, a common page size
uintptr_t page_start = (uintptr_t)code & ~(pagesize - 1);
mprotect((void *)page_start, pagesize, PROT_READ | PROT_EXEC);
func();
return 0;
}

9
srcs/woody.c
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@ -45,7 +45,6 @@ int get_load_segment(t_efl_content *woody, int start, bool executable)
return -1;
}
int32_t find_jmp(char *code, size_t len)
{
char *jump = JUMP;
@ -70,7 +69,7 @@ void inject(t_efl_content *woody)
size_t payload_off = woody->Phdr[i].p_offset + woody->Phdr[i].p_memsz;
printf("Old entry : %ld\n", woody->Ehdr->e_entry);
printf("Code_cave_start = %ld\n", woody->Phdr[i].p_offset);
printf("Code_cave_start = %ld\n", payload_off);
printf("Code_cave_size = %ld\n", code_cave_size);
printf("Payload size = %ld\n", len_payload);
@ -80,12 +79,11 @@ void inject(t_efl_content *woody)
ft_memcpy(&payload[jmp_index + 1], &backward_len, sizeof(backward_len));
ft_memcpy(woody->file + payload_off, payload, len_payload);
printf("Backward offset = %d\n", backward_len);
printf("Backward offset = %d (%x)\n", backward_len, backward_len);
woody->Ehdr->e_entry = payload_off;
woody->Phdr[i].p_filesz += len_payload;
woody->Phdr[i].p_memsz += len_payload;
woody->file_size += len_payload;
printf("New entry = %ld\n", woody->Ehdr->e_entry);
}
@ -93,7 +91,7 @@ void inject(t_efl_content *woody)
int get_elf_sections(t_efl_content *woody)
{
woody->Ehdr = (Elf64_Ehdr *)fetch(woody->file, woody->file_size, 0, sizeof(Elf64_Ehdr));
if (!woody->Ehdr || !elf_magic_numbers(woody->file) || woody->Ehdr->e_ident[EI_CLASS] != 2)
if (!woody->Ehdr || !elf_magic_numbers(woody->file) || woody->Ehdr->e_ident[EI_CLASS] != ELFCLASS64)
{
ft_printf("Error: \'%s\' is not a valid 64-bit ELF file\n", woody->file_path);
return EXIT_FAILURE;
@ -150,7 +148,6 @@ int prepare_injection(t_efl_content *woody)
ft_memcpy(woody_file, woody->file, woody->file_size);
// encrypt(woody_file, strtab_header->sh_offset , strtab_header->sh_size);
munmap(woody_file, woody->file_size);
save_elf("woody", woody_file, woody->file_size);
free(woody_file);