The client will search for hooks, check crc headers, check for proxies, lots of other stuff.
Anyway here are all of the functions tqwea.dll used to use (now in conquer.exe), I'll highlight some interesting ones you may look at.
Code:
> KERNEL32.dll: LocalAlloc, LeaveCriticalSection, TlsGetValue, EnterCriticalSection, GlobalReAlloc, GlobalHandle, InitializeCriticalSection, TlsAlloc, TlsSetValue, LocalReAlloc, DeleteCriticalSection, TlsFree, SetErrorMode, InterlockedIncrement, GlobalGetAtomNameA, GetFileAttributesA, lstrcmpW, GlobalFindAtomA, GlobalFlags, GetCPInfo, GetOEMCP, HeapFree, HeapAlloc, TerminateProcess, UnhandledExceptionFilter, SetUnhandledExceptionFilter, GetSystemTimeAsFileTime, VirtualAlloc, HeapReAlloc, InterlockedDecrement, GetProcessHeap, RtlUnwind, RaiseException, ExitProcess, HeapSize, GetACP, IsValidCodePage, LCMapStringA, LCMapStringW, HeapDestroy, HeapCreate, VirtualFree, GetStdHandle, GetTimeZoneInformation, SetHandleCount, GetFileType, GetStartupInfoA, FreeEnvironmentStringsA, GetEnvironmentStrings, FreeEnvironmentStringsW, GetEnvironmentStringsW, QueryPerformanceCounter, GetStringTypeA, GetStringTypeW, GetUserDefaultLCID, EnumSystemLocalesA, IsValidLocale, SetStdHandle, GetConsoleCP, GetConsoleMode, GetLocaleInfoW, WriteConsoleA, GetConsoleOutputCP, WriteConsoleW, SetEnvironmentVariableA, GetModuleFileNameW, GlobalAddAtomA, GlobalDeleteAtom, GetCurrentThread, GetCurrentThreadId, ConvertDefaultLocale, EnumResourceLanguagesA, GetLocaleInfoA, lstrcmpA, GetFullPathNameA, GetVolumeInformationA, FindClose, DuplicateHandle, SetEndOfFile, UnlockFile, LockFile, FlushFileBuffers, GetThreadLocale, SetLastError, FormatMessageA, LocalFree, CompareStringA, GetVersion, lstrlenA, CompareStringW, InterlockedExchange, GlobalFree, GlobalUnlock, GlobalLock, GlobalAlloc, lstrcpyA, FindFirstFileA, Module32First, CreateToolhelp32Snapshot, GetCurrentProcessId, FindResourceA, LoadResource, LockResource, SizeofResource, QueryDosDeviceA, GetLogicalDriveStringsA, ReadFile, GetFileSize, GetSystemDirectoryA, GetModuleFileNameA, SetFilePointer, WinExec, FreeLibrary, GetModuleHandleA, GetCurrentProcess, DeleteFileA, IsBadReadPtr, GetProcAddress, GetVersionExA, LoadLibraryA, WideCharToMultiByte, CreateFileW, FileTimeToSystemTime, MultiByteToWideChar, FileTimeToLocalFileTime, GetFileTime, Process32Next, Process32First, WriteFile, GetLastError, UnmapViewOfFile, ReadProcessMemory, MapViewOfFile, VirtualAllocEx, CreateFileMappingA, IsDebuggerPresent, Module32Next, CreateFileA, OpenProcess, WaitForSingleObject, CreateThread, Sleep, GetTickCount, WritePrivateProfileStringA, CloseHandle, GetCommandLineA, GetPrivateProfileStringA
> USER32.dll: GrayStringA, DrawTextExA, DrawTextA, TabbedTextOutA, ClientToScreen, ShowWindow, SetWindowTextA, RegisterWindowMessageA, LoadIconA, WinHelpA, GetCapture, SetPropA, GetPropA, RemovePropA, IsWindow, GetForegroundWindow, GetDlgItem, GetTopWindow, DestroyWindow, GetMessageTime, GetMessagePos, MapWindowPoints, SetForegroundWindow, GetMenu, GetClassInfoExA, GetClassInfoA, RegisterClassA, AdjustWindowRectEx, CopyRect, PtInRect, GetDlgCtrlID, DefWindowProcA, CallWindowProcA, SetWindowLongA, SetWindowPos, SystemParametersInfoA, IsIconic, GetWindowPlacement, GetWindowRect, LoadCursorA, GetDC, ReleaseDC, GetSysColor, UnregisterClassA, [B][COLOR="Red"]UnhookWindowsHookEx[/COLOR][/B], GetLastActivePopup, IsWindowEnabled, EnableWindow, MessageBoxA, SetCursor, [B][COLOR="Red"]SetWindowsHookExA[/COLOR][/B], [B][COLOR="Red"]CallNextHookEx[/COLOR][/B], GetMessageA, TranslateMessage, DispatchMessageA, GetActiveWindow, IsWindowVisible, GetKeyState, PeekMessageA, GetCursorPos, ValidateRect, PostMessageA, PostQuitMessage, SetMenuItemBitmaps, GetMenuCheckMarkDimensions, LoadBitmapA, GetFocus, ModifyMenuA, DestroyMenu, CreateWindowExA, EnableMenuItem, CheckMenuItem, GetSystemMetrics, GetMenuState, GetMenuItemID, GetMenuItemCount, GetSubMenu, CharUpperA, FindWindowExA, FindWindowA, GetClassLongA, GetClientRect, GetWindowLongA, GetParent, GetDesktopWindow, GetWindow, wsprintfW, [B][COLOR="Red"]EnumChildWindows[/COLOR][/B], GetWindowTextA, GetClassNameA, GetWindowThreadProcessId, [B][COLOR="Red"]EnumWindows[/COLOR][/B], SendMessageA, wsprintfA, GetSysColorBrush
> GDI32.dll: DeleteDC, GetStockObject, ScaleWindowExtEx, SetWindowExtEx, ScaleViewportExtEx, SetViewportExtEx, OffsetViewportOrgEx, SetViewportOrgEx, SelectObject, Escape, ExtTextOutA, TextOutA, RectVisible, PtVisible, GetDeviceCaps, SetMapMode, RestoreDC, SaveDC, DeleteObject, SetBkColor, SetTextColor, GetClipBox, CreateBitmap
> comdlg32.dll: GetFileTitleA
> WINSPOOL.DRV: ClosePrinter, DocumentPropertiesA, OpenPrinterA
> ADVAPI32.dll: RegSetValueExA, RegCreateKeyExA, [B][COLOR="Red"]RegQueryValueA[/COLOR][/B], RegEnumKeyA, RegDeleteKeyA, RegOpenKeyExA, RegQueryValueExA, [B][COLOR="Red"]RegOpenKeyA[/COLOR][/B], RegCloseKey, AdjustTokenPrivileges, LookupPrivilegeValueA, OpenProcessToken
> SHLWAPI.dll: PathStripToRootA, PathIsUNCA, PathFindExtensionA, PathFindFileNameA
> WININET.dll: [B][COLOR="Red"]InternetOpenA[/COLOR][/B], InternetGetConnectedState, [B][COLOR="Red"]InternetReadFile[/COLOR][/B], [B][COLOR="Red"]HttpOpenRequestA[/COLOR][/B], InternetConnectA, InternetCloseHandle, [B][COLOR="Red"]HttpSendRequestA[/COLOR][/B], HttpQueryInfoA
> VERSION.dll: GetFileVersionInfoA, GetFileVersionInfoSizeA, VerQueryValueA
