CVE-2017-8682 : Detail

CVE-2017-8682

8.8
/
High
A03-Injection
23.96%V3
Network
2017-09-13
01h00 +00:00
2024-09-17
02h36 +00:00
CVE.org
NVD
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CVE Descriptions

Windows graphics on 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, and 1703, Windows Server 2016, Microsoft Office Word Viewer, Microsoft Office 2007 Service Pack 3 , and Microsoft Office 2010 Service Pack 2 allows an attacker to execute remote code by the way it handles embedded fonts, aka "Win32k Graphics Remote Code Execution Vulnerability". This CVE ID is unique from CVE-2017-8683.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-20 Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 8.8 HIGH CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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.

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.

High

There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.

Availability Impact

This metric measures the impact to the availability of the impacted component resulting from a successfully exploited vulnerability.

High

There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

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 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C [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 : 42744

Publication date : 2017-09-17 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1273 We have encountered a number of Windows kernel crashes in the win32k.sys driver while processing corrupted TTF font files. The most frequent one occurring for the bug reported here is as follows: --- PAGE_FAULT_IN_NONPAGED_AREA (50) Invalid system memory was referenced. This cannot be protected by try-except, it must be protected by a Probe. Typically the address is just plain bad or it is pointing at freed memory. Arguments: Arg1: 8273777f, memory referenced. Arg2: 00000000, value 0 = read operation, 1 = write operation. Arg3: 919c279f, If non-zero, the instruction address which referenced the bad memory address. Arg4: 00000000, (reserved) Debugging Details: ------------------ FAULTING_IP: win32k!bGeneratePath+60 919c279f 8b0f mov ecx,dword ptr [edi] MM_INTERNAL_CODE: 0 DEFAULT_BUCKET_ID: WIN7_DRIVER_FAULT BUGCHECK_STR: 0x50 PROCESS_NAME: csrss.exe CURRENT_IRQL: 0 ANALYSIS_VERSION: 6.3.9600.17237 (debuggers(dbg).140716-0327) x86fre LAST_CONTROL_TRANSFER: from 91a9b6af to 919c279f STACK_TEXT: 99ee4a14 91a9b6af 00000000 000003e0 00000010 win32k!bGeneratePath+0x60 99ee4a40 91a9a105 fbc62cf0 00000005 faebeda0 win32k!ttfdQueryTrueTypeOutline+0x79 99ee4a90 91a82fef 00000000 fbc62cf0 00000005 win32k!ttfdSemQueryTrueTypeOutline+0x45 99ee4ad8 91a65175 00000000 fbc62cf0 00000005 win32k!PDEVOBJ::QueryTrueTypeOutline+0x3e 99ee4b90 91a5cd60 fbc62cf0 fbc62cf0 00000003 win32k!GreGetGlyphOutlineInternal+0x4f5 99ee4c0c 8286c87a 2801007e 0000003b 00000003 win32k!NtGdiGetGlyphOutline+0x95 99ee4c0c 770570b4 2801007e 0000003b 00000003 nt!KiFastCallEntry+0x12a WARNING: Frame IP not in any known module. Following frames may be wrong. 002df760 00000000 00000000 00000000 00000000 0x770570b4 --- We have observed the invalid memory addresses accessed by the win32k!bGeneratePath function to be seemingly "wild", e.g. 0x8273777f, 0xe9849de5, 0xc7617bc7, 0xf2edc7eb etc. The above crash dump comes from an old version of Windows 7 32-bit, because symbols for win32k.sys on the latest build are currently unavailable on the Microsoft Symbol Server. Nevertheless, a crash summary from an up-to-date system is as follows: --- cut --- PAGE_FAULT_IN_NONPAGED_AREA (50) Invalid system memory was referenced. This cannot be protected by try-except, it must be protected by a Probe. Typically the address is just plain bad or it is pointing at freed memory. Arguments: Arg1: 8128f57d, memory referenced. Arg2: 00000000, value 0 = read operation, 1 = write operation. Arg3: 925375f6, If non-zero, the instruction address which referenced the bad memory address. Arg4: 00000000, (reserved) Debugging Details: ------------------ FAULTING_IP: win32k!PATHOBJ_bCloseFigure+76 925375f6 8b0f mov ecx,dword ptr [edi] MM_INTERNAL_CODE: 0 DEFAULT_BUCKET_ID: WIN7_DRIVER_FAULT BUGCHECK_STR: 0x50 PROCESS_NAME: csrss.exe CURRENT_IRQL: 0 ANALYSIS_VERSION: 6.3.9600.17237 (debuggers(dbg).140716-0327) x86fre LAST_CONTROL_TRANSFER: from 9261b9c8 to 925375f6 STACK_TEXT: WARNING: Stack unwind information not available. Following frames may be wrong. 89277a10 9261b9c8 00000000 00000150 00000010 win32k!PATHOBJ_bCloseFigure+0x76 89277a3c 9261a316 fbb26cf0 0000000c fba36f38 win32k!XLATEOBJ_hGetColorTransform+0x423bf 89277a8c 926019b4 00000000 fbb26cf0 0000000c win32k!XLATEOBJ_hGetColorTransform+0x40d0d 89277ad4 925e33e5 00000000 fbb26cf0 0000000c win32k!XLATEOBJ_hGetColorTransform+0x283ab 89277b90 925dafcc fbb26cf0 fbb26cf0 00000003 win32k!XLATEOBJ_hGetColorTransform+0x9ddc 89277c0c 82837986 2201061c 00000029 00000003 win32k!XLATEOBJ_hGetColorTransform+0x19c3 89277c0c 772b6c74 2201061c 00000029 00000003 nt!KiSystemServicePostCall 0019f608 00000000 00000000 00000000 00000000 0x772b6c74 --- cut --- While the above crashes are the most common ones, we have also encountered bugchecks (likely caused by the same issue) at the following other locations on old Windows 7 32-bit: --- win32k!vQsplineToPolyBezier+43 91522614 8b4608 mov eax,dword ptr [esi+8] --- win32k!vQsplineToPolyBezier+83 92292654 8941fc mov dword ptr [ecx-4],eax --- ... and on latest Windows 7 32-bit: --- win32k!EngDeleteRgn+3293 91e0747c 8b460c mov eax,dword ptr [esi+0Ch] --- The crash in win32k!vQsplineToPolyBezier+83 strongly suggests that the failures are caused or may lead to memory corruption, and consequently to arbitrary code execution. While we have not determined the specific root cause of the vulnerability, we have pinpointed the offending mutations to reside in the "fpgm" table. In case of the few samples we have examined, the problem seems to stem from changing one of the instructions in the FPGM program to "FLIPPT". The issue reproduces on Windows 7 (other platforms unchecked). It is easiest to reproduce with Special Pools enabled for win32k.sys (leading to an immediate crash when the bug is triggered), but it it also possible to observe a system crash on a default Windows installation. In order to reproduce the problem with the provided samples, it is necessary to use a custom program which calls the GetGlyphOutline() API with various parameters over all of the font's glyphs. Attached is an archive with several proof-of-concept mutated TTF files. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/42744.zip

Products Mentioned

Configuraton 0

Microsoft>>Office_2007 >> Version -

Microsoft>>Office_2010 >> Version -

    Microsoft>>Office_word_viewer >> Version -

    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

    http://www.securitytracker.com/id/1039352
    Tags : vdb-entry, x_refsource_SECTRACK
    http://www.securityfocus.com/bid/100772
    Tags : vdb-entry, x_refsource_BID
    https://www.exploit-db.com/exploits/42744/
    Tags : exploit, x_refsource_EXPLOIT-DB