Shellcode Reference — Compile, Extract, Test

Linux Assembly compiling instruction:

• For x32:

$ nasm -f elf32 <file_assembly.asm> -o <output_file.o>
$ ld -m elf_i386 <asm_output_file.o> -o <binary_name>

• For x64:

$ nasm -f elf_x86_64 <file_assembly.asm> -o <output_file.o>
$ ld -m elf_x86_64 <asm_output_file.o> -o <binary_name>

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Get Hex value:

if [ -z "$1" ]
then
  echo "Usage: $0 <path to executable>"
  exit
fi
 objdump -d $1 | grep '[0-9a-f]:' | grep -v 'file' | cut -f2 -d: | cut -f1-6 -d' ' | tr -s ' ' | tr '\t' ' ' | sed 's/ $//g' | sed 's/ /\\x/g' | paste -d '' -s |  sed 's/^/"/' | sed 's/$/"/g'

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Shellcode Tester (Not work for me ParotOS):

char shellcode[] = "HexValue";
int main(){
   (*(void(*)())shellcode)();
   return 0;
}

• Compile with gcc:

$ gcc -m<32/64> -z execstack -fno-stack-protector -no-pie <test_shell.c> -o <test_shell_binary>

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