CVE-2016-3216 : Detail

CVE-2016-3216

4.3
/
Medium
A01-Broken Access Control
5.68%V3
Network
2016-06-15
23h00 +00:00
2018-10-12
17h57 +00:00
CVE.org
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CVE Descriptions

GDI32.dll in the Graphics component in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8.1, Windows Server 2012 Gold and R2, Windows RT 8.1, and Windows 10 Gold and 1511 allows remote attackers to bypass the ASLR protection mechanism via unspecified vectors, aka "Windows Graphics Component Information Disclosure Vulnerability."

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 4.3 MEDIUM CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/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.

Network

A vulnerability exploitable with network access means the vulnerable component is bound to the network stack and the attacker's path is through OSI layer 3 (the network layer). Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable one or more network hops away (e.g. across layer 3 boundaries from routers).

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.

None

The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.

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.

Low

There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is constrained. The information disclosure does not cause a direct, serious loss to the impacted component.

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

 nvd@nist.gov
V2 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N nvd@nist.gov

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 : 39990

Publication date : 2016-06-20 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=757 As clearly visible in the EMF (Enhanced Metafile) image format specification ([MS-EMF]), there are multiple records which deal with DIBs (Device Independent Bitmaps). Examples of such records are EMR_ALPHABLEND, EMR_BITBLT, EMR_MASKBLT, EMR_PLGBLT, EMR_SETDIBITSTODEVICE, EMR_STRETCHBLT, EMR_STRETCHDIBITS, EMR_TRANSPARENTBLT, EMR_CREATEDIBPATTERNBRUSHPT, EMR_CREATEMONOBRUSH and EMR_EXTCREATEPEN. The DIB format is relatively complex, since the headers and data itself may be interpreted in a number of ways depending on a combination of settings found in the headers. For example, various (de)compression algorithms can be applied to the data depending on the BITMAPINFOHEADER.biCompression field, and the image data can either be treated as RGB, or indexes into a color palette, depending on BITMAPINFOHEADER.biBitCount. The Windows API functions taking DIBs on input work under the assumption that the passed bitmap is valid, and particularly that there is enough memory in the image buffer to cover all picture pixels. The EMF format essentially works as a proxy for GDI calls, and therefore the burden of a thorough DIB sanitization is on the underlying implementation. We have found the sanitization performed by a number of EMF record handlers in the gdi32.dll user-mode library to be insufficient, leading to heap-based out-of-bounds reads while parsing/loading the bitmap, and in some cases to a subsequent memory disclosure. Since the bugs are present in a core Windows library, all of its clients which allow the loading of arbitrary EMF images are affected. The severity is highest for software which makes it possible to recover the disclosed heap bytes, as an attacker could then steal secret information from the program's memory, or defeat the ASLR exploit mitigation mechanism to reliably take advantage of another vulnerability. The DIB-embedding records follow a common scheme: they include four fields, denoting the offsets and lengths of the DIB header and DIB data, respectively (named offBmiSrc, cbBmiSrc, offBitsSrc, cbBitsSrc). A correct implementation should: 1) Verify that cbBmiSrc is within expected bounds, accounting for the DIB header, color palette etc. 2) Verify that the (offBmiSrc, offBmiSrc + cbBmiSrc) region resides within the record buffer's area. 3) Verify that cbBitsSrc is within expected bounds, and especially that it is larger or equal the expected number of bitmap bytes. 4) Verify that the (offBitsSrc, offBitsSrc + cbBitsSrc) region resides within the record buffer's area. If any of the above steps is not executed correctly, it is possible for an attacker to craft an EMF file which causes gdi32.dll to attempt to create DIB objects based on out-of-bounds memory. As it turns out, many EMF record handlers fail to perform exhaustive sanitization. Our analysis was based on a 32-bit gdi32.dll file found in the C:\Windows\SysWOW64 directory on a fully patched Windows 7 operating system. The problems we have discovered are as follows: -------------------------------------------------------------------------------- - MRALPHABLEND::bPlay - MRBITBLT::bPlay - MRMASKBLT::bPlay - MRPLGBLT::bPlay - MRSTRETCHBLT::bPlay - MRTRANSPARENTBLT::bPlay -------------------------------------------------------------------------------- Conditions (1) and (2) are not checked. -------------------------------------------------------------------------------- - MRSETDIBITSTODEVICE::bPlay -------------------------------------------------------------------------------- Condition (3) is not checked. -------------------------------------------------------------------------------- - MRSTRETCHDIBITS::bPlay -------------------------------------------------------------------------------- Conditions (1) and (3) are not checked. -------------------------------------------------------------------------------- - MRSTRETCHDIBITS::bPlay - MRCREATEMONOBRUSH::bPlay - MREXTCREATEPEN::bPlay -------------------------------------------------------------------------------- Conditions (1), (2), (3) and (4) are not checked. Please note that seeing the general class of bugs and how widespread it is across various DIB-related EMF handlers, we only performed a cursory analysis to see which checks are missing from which functions. It is possible that there are more missing sanity checks in some of them that we haven't noted in the list above. We recommend performing a careful security audit of the handlers dealing with DIBs, to ensure they perform correct and complete sanitization of the input data. In order to demonstrate that the bug is real and affects Internet Explorer (among other targets - Microsoft Office 2013 was also tested), we have hacked up a proof-of-concept EMF file, which includes a specially crafted EMR_STRETCHBLT record, which in turn contains a 8 bpp DIB, whose palette entries go beyond the record area. Each time the image is opened in Internet Explorer, it is displayed differently, as the garbage heap bytes beyond the allocated buffer change. Attached is also a screenshot of the proof of concept picture, as displayed by Internet Explorer 11 on Windows 7 when opened three times in a row. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/39990.zip

Products Mentioned

Configuraton 0

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1511

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_vista >> Version *

References

https://www.exploit-db.com/exploits/39990/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1036101
Tags : vdb-entry, x_refsource_SECTRACK