On Monday, February 21, 2000 at 3:00:00 PM UTC+7, Gary Nebbett wrote:
"Christian Zietz" <czietz@gmx.net> wrote in message news:38AEAC16.F6FC7DA9@gmx.net...
is there a possibility to load an executable from RAM instead of from a file? What I want to do is: the EXE is loaded into memory by my application, the import table is patched, then the Windows loader
becomes active and creates a new process.
As Tomas pointed out, depending on exactly what you want to do, it might not be necessary to create a new process from an in-memory image. If you really do need to create a process from an in-memory image on NT then you might try the following, which assumes that the in-memory image originates from a binary resource bound to the executable.
Gary
#define WIN32_NO_STATUS
#include <windows.h>
#undef WIN32_NO_STATUS
namespace NT {
extern "C" {
#pragma warning(disable: 4005) // macro redefinition
#include <ntddk.h>
#pragma warning(default: 4005)
}
}
using NT::NTSTATUS;
typedef struct _DEBUG_CONTROL {
ULONG L0 : 1;
ULONG G0 : 1;
ULONG L1 : 1;
ULONG G1 : 1;
ULONG L2 : 1;
ULONG G2 : 1;
ULONG L3 : 1;
ULONG G3 : 1;
ULONG LE : 1;
ULONG GE : 1;
ULONG : 3;
ULONG GD : 1;
ULONG : 2;
ULONG RWE0 : 2;
ULONG LEN0 : 2;
ULONG RWE1 : 2;
ULONG LEN1 : 2;
ULONG RWE2 : 2;
ULONG LEN2 : 2;
ULONG RWE3 : 2;
ULONG LEN3 : 2;
} DEBUG_CONTROL, *PDEBUG_CONTROL;
VOID preppatch()
{
CONTEXT context = {CONTEXT_DEBUG_REGISTERS};
PDEBUG_CONTROL dr7 = PDEBUG_CONTROL(&context.Dr7);
context.Dr0 = ULONG(GetProcAddress(GetModuleHandle("ntdll.dll"), "ZwCreateThread"));
dr7->L0 = 1, dr7->RWE0 = 0, dr7->LEN0 = 0;
SetThreadContext(GetCurrentThread(), &context);
}
LONG patch(PEXCEPTION_POINTERS ep)
{
if (ep->ExceptionRecord->ExceptionCode == EXCEPTION_SINGLE_STEP) {
HANDLE hProcess = PHANDLE(ep->ContextRecord->Esp)[4];
PCONTEXT context = ((PCONTEXT*)(ep->ContextRecord->Esp))[6];
NT::PROCESS_BASIC_INFORMATION pbi;
NT::NtQueryInformationProcess(hProcess, NT::ProcessBasicInformation, &pbi, sizeof pbi, 0);
PVOID x; ReadProcessMemory(hProcess, PCHAR(pbi.PebBaseAddress) + 8, &x, sizeof x, 0);
NT::ZwUnmapViewOfSection(hProcess, x);
HRSRC hRsrc = FindResource(0, "Image", "EXE");
HGLOBAL hGlobal = LoadResource(0, hRsrc);
PVOID p = LockResource(hGlobal);
PIMAGE_NT_HEADERS nt = PIMAGE_NT_HEADERS(PCHAR(p) + PIMAGE_DOS_HEADER(p)->e_lfanew);
PVOID q = VirtualAllocEx(hProcess,
PVOID(nt->OptionalHeader.ImageBase),
nt->OptionalHeader.SizeOfImage,
MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
WriteProcessMemory(hProcess, PCHAR(q), PCHAR(p), 0x1000, 0);
PIMAGE_SECTION_HEADER sect = IMAGE_FIRST_SECTION(nt);
for (ULONG i = 0; i < nt->FileHeader.NumberOfSections; i++)
WriteProcessMemory(hProcess,
PCHAR(q) + sect[i].VirtualAddress,
PCHAR(p) + sect[i].PointerToRawData,
sect[i].SizeOfRawData, 0);
WriteProcessMemory(hProcess, PCHAR(pbi.PebBaseAddress) + 8, &q, sizeof q, 0);
context->Eax = ULONG(q) + nt->OptionalHeader.AddressOfEntryPoint;
ep->ContextRecord->Dr7 = 0;
return EXCEPTION_CONTINUE_EXECUTION;
}
return EXCEPTION_CONTINUE_SEARCH;
}
int main(int argc, char *argv[])
{
PROCESS_INFORMATION pi;
STARTUPINFO si = {sizeof si};
__try {
preppatch();
CreateProcess(0, "Explorer", 0, 0, FALSE, 0, 0, 0, &si, &pi);
}
__except (patch(GetExceptionInformation())) {}
return 0;
}
Could you help me explain the process of this stuff in a narrative way, perhaps?
and i dont know what is _try and _except
Thank you!
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