Windows的PE加载器在启动程序的时候，会将磁盘上的文件加载到内存，然后做很多操作，如函数导入表重定位，变量预处理之类的。这位仁兄等于是自己写了一个PE加载器。直接将内存中的程序启动。记得以前的“红色代码”病毒也有相同的特性。
直接启动内存中的程序相当于加了一个壳，可以把程序加密保存，运行时解密到内存，然后启动，不过对于增加破解难度还要稍微复杂点。否则人家把内存中的进程DUMP出来然后修复导入表就被拖出来了。
#include " stdafx.h "
typedef IMAGE_SECTION_HEADER ( * PIMAGE_SECTION_HEADERS)[ 1 ];
// 计算对齐后的大小
unsigned long GetAlignedSize(unsigned long Origin, unsigned long Alignment)
... {
return (Origin + Alignment - 1) / Alignment * Alignment;
}
// 计算加载pe并对齐需要占用多少内存
// 未直接使用OptionalHeader.SizeOfImage作为结果是因为据说有的编译器生成的exe这个值会填0
unsigned long CalcTotalImageSize(PIMAGE_DOS_HEADER MzH
, unsigned long FileLen
, PIMAGE_NT_HEADERS peH
, PIMAGE_SECTION_HEADERS peSecH)
... {
unsigned long res;
// 计算pe头的大小
res = GetAlignedSize( peH->OptionalHeader.SizeOfHeaders
, peH->OptionalHeader.SectionAlignment
);
// 计算所有节的大小
for( int i = 0; i < peH->FileHeader.NumberOfSections; ++i)
...{
// 超出文件范围
if(peSecH[i]->PointerToRawData + peSecH[i]->SizeOfRawData > FileLen)
return 0;
else if(peSecH[i]->VirtualAddress)//计算对齐后某节的大小
...{
if(peSecH[i]->Misc.VirtualSize)
...{
res = GetAlignedSize( peSecH[i]->VirtualAddress + peSecH[i]->Misc.VirtualSize
, peH->OptionalHeader.SectionAlignment
);
}
else
...{
res = GetAlignedSize( peSecH[i]->VirtualAddress + peSecH[i]->SizeOfRawData
, peH->OptionalHeader.SectionAlignment
);
}
}
else if( peSecH[i]->Misc.VirtualSize < peSecH[i]->SizeOfRawData )
...{
res += GetAlignedSize( peSecH[i]->SizeOfRawData
, peH->OptionalHeader.SectionAlignment
);
}
else
...{
res += GetAlignedSize( peSecH[i]->Misc.VirtualSize
, peH->OptionalHeader.SectionAlignment
);
}// if_else
}// for
return res;
}
// 加载pe到内存并对齐所有节
BOOL AlignPEToMem( void * Buf
, long Len
, PIMAGE_NT_HEADERS & peH
, PIMAGE_SECTION_HEADERS & peSecH
, void *& Mem
, unsigned long & ImageSize)
... {
PIMAGE_DOS_HEADER SrcMz;// DOS头
PIMAGE_NT_HEADERS SrcPeH;// PE头
PIMAGE_SECTION_HEADERS SrcPeSecH;// 节表
SrcMz = (PIMAGE_DOS_HEADER)Buf;
if( Len < sizeof(IMAGE_DOS_HEADER) )
return FALSE;
if( SrcMz->e_magic != IMAGE_DOS_SIGNATURE )
return FALSE;
if( Len < SrcMz->e_lfanew + (long)sizeof(IMAGE_NT_HEADERS) )
return FALSE;
SrcPeH = (PIMAGE_NT_HEADERS)((int)SrcMz + SrcMz->e_lfanew);
if( SrcPeH->Signature != IMAGE_NT_SIGNATURE )
return FALSE;
if( (SrcPeH->FileHeader.Characteristics & IMAGE_FILE_DLL) ||
(SrcPeH->FileHeader.Characteristics & IMAGE_FILE_EXECUTABLE_IMAGE == 0) ||
(SrcPeH->FileHeader.SizeOfOptionalHeader != sizeof(IMAGE_OPTIONAL_HEADER)) )
...{
return FALSE;
}
SrcPeSecH = (PIMAGE_SECTION_HEADERS)((int)SrcPeH + sizeof(IMAGE_NT_HEADERS));
ImageSize = CalcTotalImageSize( SrcMz, Len, SrcPeH, SrcPeSecH);
if( ImageSize == 0 )
return FALSE;
Mem = VirtualAlloc( NULL, ImageSize, MEM_COMMIT, PAGE_EXECUTE_READWRITE); // 分配内存
if( Mem != NULL )
...{
// 计算需要复制的PE头字节数
unsigned long l = SrcPeH->OptionalHeader.SizeOfHeaders;
for( int i = 0; i < SrcPeH->FileHeader.NumberOfSections; ++i)
...{
if( (SrcPeSecH[i]->PointerToRawData) &&
(SrcPeSecH[i]->PointerToRawData < l) )
...{
l = SrcPeSecH[i]->PointerToRawData;
}
}
memmove( Mem, SrcMz, l);
peH = (PIMAGE_NT_HEADERS)((int)Mem + ((PIMAGE_DOS_HEADER)Mem)->e_lfanew);
peSecH = (PIMAGE_SECTION_HEADERS)((int)peH + sizeof(IMAGE_NT_HEADERS));
void *Pt = (void *)((unsigned long)Mem
+ GetAlignedSize( peH->OptionalHeader.SizeOfHeaders
, peH->OptionalHeader.SectionAlignment)
);
for( i = 0; i < peH->FileHeader.NumberOfSections; ++i)
...{
// 定位该节在内存中的位置
if(peSecH[i]->VirtualAddress)
Pt = (void *)((unsigned long)Mem + peSecH[i]->VirtualAddress);
if(peSecH[i]->SizeOfRawData)
...{
// 复制数据到内存
memmove(Pt, (const void *)((unsigned long)(SrcMz) + peSecH[i]->PointerToRawData), peSecH[i]->SizeOfRawData);
if(peSecH[i]->Misc.VirtualSize < peSecH[i]->SizeOfRawData)
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->SizeOfRawData, peH->OptionalHeader.SectionAlignment));
else // pt 定位到下一节开始位置
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->Misc.VirtualSize, peH->OptionalHeader.SectionAlignment));
}
else
...{
Pt = (void *)((unsigned long)Pt + GetAlignedSize(peSecH[i]->Misc.VirtualSize, peH->OptionalHeader.SectionAlignment));
}
}
}
return TRUE;
}
typedef void * (__stdcall * pfVirtualAllocEx)(unsigned long , void * , unsigned long , unsigned long , unsigned long );
pfVirtualAllocEx MyVirtualAllocEx = NULL;
BOOL IsNT()
... {
return MyVirtualAllocEx!=NULL;
}
// 生成外壳程序命令行
char * PrepareShellExe( char * CmdParam, unsigned long BaseAddr, unsigned long ImageSize)
... {
if(IsNT())
...{
char *Buf = new char[256];
memset(Buf, 0, 256);
GetModuleFileName(0, Buf, 256);
strcat(Buf, CmdParam);
return Buf; // 请记得释放内存;-)
}
else
...{
// Win98下的处理请参考原文;-)
// http://community.csdn.net/Expert/topic/4416/4416252.xml?temp=8.709133E-03
return NULL;
}
}
// 是否包含可重定向列表
BOOL HasRelocationTable(PIMAGE_NT_HEADERS peH)
... {
return (peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress)
&& (peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].Size);
}
#pragma pack(push, 1 )
typedef struct ... {
unsigned long VirtualAddress;
unsigned long SizeOfBlock;
} * PImageBaseRelocation;
#pragma pack(pop)
// 重定向PE用到的地址
void DoRelocation(PIMAGE_NT_HEADERS peH, void * OldBase, void * NewBase)
... {
unsigned long Delta = (unsigned long)NewBase - peH->OptionalHeader.ImageBase;
PImageBaseRelocation p = (PImageBaseRelocation)((unsigned long)OldBase
+ peH->OptionalHeader.DataDirectory[IMAGE_DIRECTORY_ENTRY_BASERELOC].VirtualAddress);
while(p->VirtualAddress + p->SizeOfBlock)
...{
unsigned short *pw = (unsigned short *)((int)p + sizeof(*p));
for(unsigned int i=1; i <= (p->SizeOfBlock - sizeof(*p)) / 2; ++i)
...{
if((*pw) & 0xF000 == 0x3000)...{
unsigned long *t = (unsigned long *)((unsigned long)(OldBase) + p->VirtualAddress + ((*pw) & 0x0FFF));
*t += Delta;
}
++pw;
}
p = (PImageBaseRelocation)pw;
}
}
// 卸载原外壳占用内存
BOOL UnloadShell(HANDLE ProcHnd, unsigned long BaseAddr)
... {
typedef unsigned long (__stdcall *pfZwUnmapViewOfSection)(unsigned long, unsigned long);
pfZwUnmapViewOfSection ZwUnmapViewOfSection = NULL;
BOOL res = FALSE;
HMODULE m = LoadLibrary("ntdll.dll");
if(m)...{
ZwUnmapViewOfSection = (pfZwUnmapViewOfSection)GetProcAddress(m, "ZwUnmapViewOfSection");
if(ZwUnmapViewOfSection)
res = (ZwUnmapViewOfSection((unsigned long)ProcHnd, BaseAddr) == 0);
FreeLibrary(m);
}
return res;
}
// 创建外壳进程并获取其基址、大小和当前运行状态
BOOL CreateChild( char * Cmd, CONTEXT & Ctx, HANDLE & ProcHnd, HANDLE & ThrdHnd,
unsigned long & ProcId, unsigned long & BaseAddr, unsigned long & ImageSize)
... {
STARTUPINFOA si;
PROCESS_INFORMATION pi;
unsigned long old;
MEMORY_BASIC_INFORMATION MemInfo;
memset(&si, 0, sizeof(si));
memset(&pi, 0, sizeof(pi));
si.cb = sizeof(si);
BOOL res = CreateProcess(NULL, Cmd, NULL, NULL, FALSE, CREATE_SUSPENDED, NULL, NULL, &si, &pi); // 以挂起方式运行进程;
if(res)...{
ProcHnd = pi.hProcess;
ThrdHnd = pi.hThread;
ProcId = pi.dwProcessId;
// 获取外壳进程运行状态，[ctx.Ebx+8]内存处存的是外壳进程的加载基址，ctx.Eax存放有外壳进程的入口地址
Ctx.ContextFlags = CONTEXT_FULL;
GetThreadContext(ThrdHnd, &Ctx);
ReadProcessMemory(ProcHnd, (void *)(Ctx.Ebx+8), &BaseAddr, sizeof(unsigned long), &old); // 读取加载基址
void *p = (void *)BaseAddr;
// 计算外壳进程占有的内存
while(VirtualQueryEx(ProcHnd, p, &MemInfo, sizeof(MemInfo)))
...{
if(MemInfo.State = MEM_FREE) break;
p = (void *)((unsigned long)p + MemInfo.RegionSize);
}
ImageSize = (unsigned long)p - (unsigned long)BaseAddr;
}
return res;
}
// 创建外壳进程并用目标进程替换它然后执行
HANDLE AttachPE( char * CmdParam, PIMAGE_NT_HEADERS peH, PIMAGE_SECTION_HEADERS peSecH,
void * Ptr, unsigned long ImageSize, unsigned long & ProcId)
... {
HANDLE res = INVALID_HANDLE_VALUE;
CONTEXT Ctx;
HANDLE Thrd;
unsigned long Addr, Size;
char *s = PrepareShellExe(CmdParam, peH->OptionalHeader.ImageBase, ImageSize);
if(s==NULL) return res;
if(CreateChild(s, Ctx, res, Thrd, ProcId, Addr, Size))...{
void *p = NULL;
unsigned long old;
if((peH->OptionalHeader.ImageBase == Addr) && (Size >= ImageSize))...{// 外壳进程可以容纳目标进程并且加载地址一致
p = (void *)Addr;
VirtualProtectEx(res, p, Size, PAGE_EXECUTE_READWRITE, &old);
}
else if(IsNT())...{
if(UnloadShell(res, Addr))...{// 卸载外壳进程占有内存
p = MyVirtualAllocEx((unsigned long)res, (void *)peH->OptionalHeader.ImageBase, ImageSize, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
}
if((p == NULL) && HasRelocationTable(peH))...{// 分配内存失败并且目标进程支持重定向
p = MyVirtualAllocEx((unsigned long)res, NULL, ImageSize, MEM_RESERVE | MEM_COMMIT, PAGE_EXECUTE_READWRITE);
if(p) DoRelocation(peH, Ptr, p); // 重定向
}
}
if(p)...{
WriteProcessMemory(res, (void *)(Ctx.Ebx+8), &p, sizeof(DWORD), &old); // 重置目标进程运行环境中的基址
peH->OptionalHeader.ImageBase = (unsigned long)p;
if(WriteProcessMemory(res, p, Ptr, ImageSize, &old))...{// 复制PE数据到目标进程
Ctx.ContextFlags = CONTEXT_FULL;
if((unsigned long)p == Addr)
Ctx.Eax = peH->OptionalHeader.ImageBase + peH->OptionalHeader.AddressOfEntryPoint; // 重置运行环境中的入口地址
else
Ctx.Eax = (unsigned long)p + peH->OptionalHeader.AddressOfEntryPoint;
SetThreadContext(Thrd, &Ctx);// 更新运行环境
ResumeThread(Thrd);// 执行
CloseHandle(Thrd);
}
else...{// 加载失败,杀掉外壳进程
TerminateProcess(res, 0);
CloseHandle(Thrd);
CloseHandle(res);
res = INVALID_HANDLE_VALUE;
}
}
else...{// 加载失败,杀掉外壳进程
TerminateProcess(res, 0);
CloseHandle(Thrd);
CloseHandle(res);
res = INVALID_HANDLE_VALUE;
}
}
delete[] s;
return res;
}
HANDLE MemExecute( void * ABuffer, long Len, char * CmdParam, unsigned long * ProcessId)
... {
HANDLE res = INVALID_HANDLE_VALUE;
PIMAGE_NT_HEADERS peH;
PIMAGE_SECTION_HEADERS peSecH;
void *Ptr;
unsigned long peSz;
if(AlignPEToMem(ABuffer, Len, peH, peSecH, Ptr, peSz))
...{
res = AttachPE(CmdParam, peH, peSecH, Ptr, peSz, *ProcessId);
VirtualFree(Ptr, peSz, MEM_DECOMMIT);
}
return res;
}
// 初始化
class CInit
... {
public:
CInit()
...{
MyVirtualAllocEx = (pfVirtualAllocEx)GetProcAddress(GetModuleHandle("Kernel32.dll"), "VirtualAllocEx");
}
} Init;
int APIENTRY WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
... {
HANDLE hFile = NULL;
hFile = ::CreateFile( "f:/SourceFromCsdn2.exe"
, FILE_ALL_ACCESS
, 0
, NULL
, OPEN_EXISTING
, FILE_ATTRIBUTE_NORMAL
, NULL
);
if( hFile == INVALID_HANDLE_VALUE )
return -1;
::SetFilePointer( hFile, 0, NULL, FILE_BEGIN);
DWORD dwFileSize = ::GetFileSize( hFile, NULL);
LPBYTE pBuf = new BYTE[dwFileSize];
memset( pBuf, 0, dwFileSize);
DWORD dwNumberOfBytesRead = 0;
::ReadFile( hFile
, pBuf
, dwFileSize
, &dwNumberOfBytesRead
, NULL
);
::CloseHandle(hFile);
unsigned long ulProcessId = 0;
MemExecute( pBuf, dwFileSize, "", &ulProcessId);
delete[] pBuf;
return 0;
}