Is it possible to replace a system dll with a proxy dll? - windows

Question

After reading this interesting article:
http://www.codeproject.com/Articles/16541/Create-your-Proxy-DLLs-automatically
I've decided to try and create a proxy dll for pure research purposes. :-)
I did all the steps on ws2_32.dll and this is the code I've got:
#include <windows.h>
#include <stdio.h>
#pragma pack(1)
HINSTANCE hLThis = 0;
HINSTANCE hL = 0;
FARPROC p[182] = {0};
BOOL WINAPI DllMain(HINSTANCE hInst,DWORD reason,LPVOID)
{
//to get indication whether we were loaded
FILE* f;
fopen_s(&f, "C:\\load.txt", "a+");
fclose(f);
if (reason == DLL_PROCESS_ATTACH)
{
hLThis = hInst;
hL = LoadLibrary("ws2_32_.dll");
if (!hL) return false;
p[0] = GetProcAddress(hL,"FreeAddrInfoEx");
p[1] = GetProcAddress(hL,"FreeAddrInfoExW");
p[2] = GetProcAddress(hL,"FreeAddrInfoW");
p[3] = GetProcAddress(hL,"GetAddrInfoExA");
p[4] = GetProcAddress(hL,"GetAddrInfoExW");
p[5] = GetProcAddress(hL,"GetAddrInfoW");
p[6] = GetProcAddress(hL,"GetNameInfoW");
p[7] = GetProcAddress(hL,"InetNtopW");
p[8] = GetProcAddress(hL,"InetPtonW");
p[9] = GetProcAddress(hL,"SetAddrInfoExA");
p[10] = GetProcAddress(hL,"SetAddrInfoExW");
p[11] = GetProcAddress(hL,"WEP");
p[12] = GetProcAddress(hL,"WPUCompleteOverlappedRequest");
p[13] = GetProcAddress(hL,"WSAAccept");
p[14] = GetProcAddress(hL,"WSAAddressToStringA");
p[15] = GetProcAddress(hL,"WSAAddressToStringW");
p[16] = GetProcAddress(hL,"WSAAdvertiseProvider");
p[17] = GetProcAddress(hL,"WSAAsyncGetHostByAddr");
p[18] = GetProcAddress(hL,"WSAAsyncGetHostByName");
p[19] = GetProcAddress(hL,"WSAAsyncGetProtoByName");
p[20] = GetProcAddress(hL,"WSAAsyncGetProtoByNumber");
p[21] = GetProcAddress(hL,"WSAAsyncGetServByName");
p[22] = GetProcAddress(hL,"WSAAsyncGetServByPort");
p[23] = GetProcAddress(hL,"WSAAsyncSelect");
p[24] = GetProcAddress(hL,"WSACancelAsyncRequest");
p[25] = GetProcAddress(hL,"WSACancelBlockingCall");
p[26] = GetProcAddress(hL,"WSACleanup");
p[27] = GetProcAddress(hL,"WSACloseEvent");
p[28] = GetProcAddress(hL,"WSAConnect");
p[29] = GetProcAddress(hL,"WSAConnectByList");
p[30] = GetProcAddress(hL,"WSAConnectByNameA");
p[31] = GetProcAddress(hL,"WSAConnectByNameW");
p[32] = GetProcAddress(hL,"WSACreateEvent");
p[33] = GetProcAddress(hL,"WSADuplicateSocketA");
p[34] = GetProcAddress(hL,"WSADuplicateSocketW");
p[35] = GetProcAddress(hL,"WSAEnumNameSpaceProvidersA");
p[36] = GetProcAddress(hL,"WSAEnumNameSpaceProvidersExA");
p[37] = GetProcAddress(hL,"WSAEnumNameSpaceProvidersExW");
p[38] = GetProcAddress(hL,"WSAEnumNameSpaceProvidersW");
p[39] = GetProcAddress(hL,"WSAEnumNetworkEvents");
p[40] = GetProcAddress(hL,"WSAEnumProtocolsA");
p[41] = GetProcAddress(hL,"WSAEnumProtocolsW");
p[42] = GetProcAddress(hL,"WSAEventSelect");
p[43] = GetProcAddress(hL,"WSAGetLastError");
p[44] = GetProcAddress(hL,"WSAGetOverlappedResult");
p[45] = GetProcAddress(hL,"WSAGetQOSByName");
p[46] = GetProcAddress(hL,"WSAGetServiceClassInfoA");
p[47] = GetProcAddress(hL,"WSAGetServiceClassInfoW");
p[48] = GetProcAddress(hL,"WSAGetServiceClassNameByClassIdA");
p[49] = GetProcAddress(hL,"WSAGetServiceClassNameByClassIdW");
p[50] = GetProcAddress(hL,"WSAHtonl");
p[51] = GetProcAddress(hL,"WSAHtons");
p[52] = GetProcAddress(hL,"WSAInstallServiceClassA");
p[53] = GetProcAddress(hL,"WSAInstallServiceClassW");
p[54] = GetProcAddress(hL,"WSAIoctl");
p[55] = GetProcAddress(hL,"WSAIsBlocking");
p[56] = GetProcAddress(hL,"WSAJoinLeaf");
p[57] = GetProcAddress(hL,"WSALookupServiceBeginA");
p[58] = GetProcAddress(hL,"WSALookupServiceBeginW");
p[59] = GetProcAddress(hL,"WSALookupServiceEnd");
p[60] = GetProcAddress(hL,"WSALookupServiceNextA");
p[61] = GetProcAddress(hL,"WSALookupServiceNextW");
p[62] = GetProcAddress(hL,"WSANSPIoctl");
p[63] = GetProcAddress(hL,"WSANtohl");
p[64] = GetProcAddress(hL,"WSANtohs");
p[65] = GetProcAddress(hL,"WSAPoll");
p[66] = GetProcAddress(hL,"WSAProviderCompleteAsyncCall");
p[67] = GetProcAddress(hL,"WSAProviderConfigChange");
p[68] = GetProcAddress(hL,"WSARecv");
p[69] = GetProcAddress(hL,"WSARecvDisconnect");
p[70] = GetProcAddress(hL,"WSARecvFrom");
p[71] = GetProcAddress(hL,"WSARemoveServiceClass");
p[72] = GetProcAddress(hL,"WSAResetEvent");
p[73] = GetProcAddress(hL,"WSASend");
p[74] = GetProcAddress(hL,"WSASendDisconnect");
p[75] = GetProcAddress(hL,"WSASendMsg");
p[76] = GetProcAddress(hL,"WSASendTo");
p[77] = GetProcAddress(hL,"WSASetBlockingHook");
p[78] = GetProcAddress(hL,"WSASetEvent");
p[79] = GetProcAddress(hL,"WSASetLastError");
p[80] = GetProcAddress(hL,"WSASetServiceA");
p[81] = GetProcAddress(hL,"WSASetServiceW");
p[82] = GetProcAddress(hL,"WSASocketA");
p[83] = GetProcAddress(hL,"WSASocketW");
p[84] = GetProcAddress(hL,"WSAStartup");
p[85] = GetProcAddress(hL,"WSAStringToAddressA");
p[86] = GetProcAddress(hL,"WSAStringToAddressW");
p[87] = GetProcAddress(hL,"WSAUnadvertiseProvider");
p[88] = GetProcAddress(hL,"WSAUnhookBlockingHook");
p[89] = GetProcAddress(hL,"WSAWaitForMultipleEvents");
p[90] = GetProcAddress(hL,"WSApSetPostRoutine");
p[91] = GetProcAddress(hL,"WSCDeinstallProvider");
p[92] = GetProcAddress(hL,"WSCDeinstallProvider32");
p[93] = GetProcAddress(hL,"WSCEnableNSProvider");
p[94] = GetProcAddress(hL,"WSCEnableNSProvider32");
p[95] = GetProcAddress(hL,"WSCEnumNameSpaceProviders32");
p[96] = GetProcAddress(hL,"WSCEnumNameSpaceProvidersEx32");
p[97] = GetProcAddress(hL,"WSCEnumProtocols");
p[98] = GetProcAddress(hL,"WSCEnumProtocols32");
p[99] = GetProcAddress(hL,"WSCGetApplicationCategory");
p[100] = GetProcAddress(hL,"WSCGetProviderInfo");
p[101] = GetProcAddress(hL,"WSCGetProviderInfo32");
p[102] = GetProcAddress(hL,"WSCGetProviderPath");
p[103] = GetProcAddress(hL,"WSCGetProviderPath32");
p[104] = GetProcAddress(hL,"WSCInstallNameSpace");
p[105] = GetProcAddress(hL,"WSCInstallNameSpace32");
p[106] = GetProcAddress(hL,"WSCInstallNameSpaceEx");
p[107] = GetProcAddress(hL,"WSCInstallNameSpaceEx32");
p[108] = GetProcAddress(hL,"WSCInstallProvider");
p[109] = GetProcAddress(hL,"WSCInstallProvider64_32");
p[110] = GetProcAddress(hL,"WSCInstallProviderAndChains64_32");
p[111] = GetProcAddress(hL,"WSCSetApplicationCategory");
p[112] = GetProcAddress(hL,"WSCSetProviderInfo");
p[113] = GetProcAddress(hL,"WSCSetProviderInfo32");
p[114] = GetProcAddress(hL,"WSCUnInstallNameSpace");
p[115] = GetProcAddress(hL,"WSCUnInstallNameSpace32");
p[116] = GetProcAddress(hL,"WSCUpdateProvider");
p[117] = GetProcAddress(hL,"WSCUpdateProvider32");
p[118] = GetProcAddress(hL,"WSCWriteNameSpaceOrder");
p[119] = GetProcAddress(hL,"WSCWriteNameSpaceOrder32");
p[120] = GetProcAddress(hL,"WSCWriteProviderOrder");
p[121] = GetProcAddress(hL,"WSCWriteProviderOrder32");
p[122] = GetProcAddress(hL,"WahCloseApcHelper");
p[123] = GetProcAddress(hL,"WahCloseHandleHelper");
p[124] = GetProcAddress(hL,"WahCloseNotificationHandleHelper");
p[125] = GetProcAddress(hL,"WahCloseSocketHandle");
p[126] = GetProcAddress(hL,"WahCloseThread");
p[127] = GetProcAddress(hL,"WahCompleteRequest");
p[128] = GetProcAddress(hL,"WahCreateHandleContextTable");
p[129] = GetProcAddress(hL,"WahCreateNotificationHandle");
p[130] = GetProcAddress(hL,"WahCreateSocketHandle");
p[131] = GetProcAddress(hL,"WahDestroyHandleContextTable");
p[132] = GetProcAddress(hL,"WahDisableNonIFSHandleSupport");
p[133] = GetProcAddress(hL,"WahEnableNonIFSHandleSupport");
p[134] = GetProcAddress(hL,"WahEnumerateHandleContexts");
p[135] = GetProcAddress(hL,"WahInsertHandleContext");
p[136] = GetProcAddress(hL,"WahNotifyAllProcesses");
p[137] = GetProcAddress(hL,"WahOpenApcHelper");
p[138] = GetProcAddress(hL,"WahOpenCurrentThread");
p[139] = GetProcAddress(hL,"WahOpenHandleHelper");
p[140] = GetProcAddress(hL,"WahOpenNotificationHandleHelper");
p[141] = GetProcAddress(hL,"WahQueueUserApc");
p[142] = GetProcAddress(hL,"WahReferenceContextByHandle");
p[143] = GetProcAddress(hL,"WahRemoveHandleContext");
p[144] = GetProcAddress(hL,"WahWaitForNotification");
p[145] = GetProcAddress(hL,"WahWriteLSPEvent");
p[146] = GetProcAddress(hL,"__WSAFDIsSet");
p[147] = GetProcAddress(hL,"accept");
p[148] = GetProcAddress(hL,"bind");
p[149] = GetProcAddress(hL,"closesocket");
p[150] = GetProcAddress(hL,"connect");
p[151] = GetProcAddress(hL,"freeaddrinfo");
p[152] = GetProcAddress(hL,"getaddrinfo");
p[153] = GetProcAddress(hL,"gethostbyaddr");
p[154] = GetProcAddress(hL,"gethostbyname");
p[155] = GetProcAddress(hL,"gethostname");
p[156] = GetProcAddress(hL,"getnameinfo");
p[157] = GetProcAddress(hL,"getpeername");
p[158] = GetProcAddress(hL,"getprotobyname");
p[159] = GetProcAddress(hL,"getprotobynumber");
p[160] = GetProcAddress(hL,"getservbyname");
p[161] = GetProcAddress(hL,"getservbyport");
p[162] = GetProcAddress(hL,"getsockname");
p[163] = GetProcAddress(hL,"getsockopt");
p[164] = GetProcAddress(hL,"htonl");
p[165] = GetProcAddress(hL,"htons");
p[166] = GetProcAddress(hL,"inet_addr");
p[167] = GetProcAddress(hL,"inet_ntoa");
p[168] = GetProcAddress(hL,"inet_ntop");
p[169] = GetProcAddress(hL,"inet_pton");
p[170] = GetProcAddress(hL,"ioctlsocket");
p[171] = GetProcAddress(hL,"listen");
p[172] = GetProcAddress(hL,"ntohl");
p[173] = GetProcAddress(hL,"ntohs");
p[174] = GetProcAddress(hL,"recv");
p[175] = GetProcAddress(hL,"recvfrom");
p[176] = GetProcAddress(hL,"select");
p[177] = GetProcAddress(hL,"send");
p[178] = GetProcAddress(hL,"sendto");
p[179] = GetProcAddress(hL,"setsockopt");
p[180] = GetProcAddress(hL,"shutdown");
p[181] = GetProcAddress(hL,"socket");
}
if (reason == DLL_PROCESS_DETACH)
{
FreeLibrary(hL);
}
return 1;
}
// FreeAddrInfoEx
extern "C" __declspec(naked) void __stdcall __E__0__()
{
__asm
{
jmp p[0*4];
}
}
// FreeAddrInfoExW
extern "C" __declspec(naked) void __stdcall __E__1__()
{
__asm
{
jmp p[1*4];
}
}
// FreeAddrInfoW
extern "C" __declspec(naked) void __stdcall __E__2__()
{
__asm
{
jmp p[2*4];
}
}
// GetAddrInfoExA
extern "C" __declspec(naked) void __stdcall __E__3__()
{
__asm
{
jmp p[3*4];
}
}
// GetAddrInfoExW
extern "C" __declspec(naked) void __stdcall __E__4__()
{
__asm
{
jmp p[4*4];
}
}
...
I've compiled it (with the .def file) and got a new proxy.dll file. :-)
So far so good. Now, on my VBox win7 x64 I've renamed the original ws2_32.dll to ws2_32_.dll, placed my proxy.dll in C:\\Windows\\System32\\ and renamed it to ws2_32.dll. I did all of this with live-cd linux because of premmisions problems.
As you can see the proxy loads ws2_32_.dll so we should be okay.
But when the system returns from boot every program uses ws2_32.dll throws an error and the file C:\\load.txt is never create.
I don't know what the guy from the article did to make it work. I've read on google that you need to place (and rename) the proxy.dll in the same directory as the program that you want to run the proxy dll with, but I am looking for a global solution.
Maybe it's a checksum problem? I've read that Microsoft uses some secret checksum on it's system PEs.
Thanks, gfgqtmakia.

Answer 1

Moved to 32bit and now it's working.
Also:
Check your proxy's dependencies, it might need additional .dlls in order to run. (Dependency Walker)
Use this guide to replace the system's .dll. This is faster than rebooting into linux.