CVE-2017-0085 : Detail

CVE-2017-0085

4.3
/
Medium
A01-Broken Access Control
5.83%V3
Network
2017-03-16
23h00 +00:00
2017-08-15
07h57 +00:00
CVE.org
NVD
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CVE Descriptions

Uniscribe in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, and Windows 7 SP1 allows remote attackers to obtain sensitive information from process memory via a crafted web site, aka "Uniscribe Information Disclosure Vulnerability." CVE-2017-0091, CVE-2017-0092, CVE-2017-0111, CVE-2017-0112, CVE-2017-0113, CVE-2017-0114, CVE-2017-0115, CVE-2017-0116, CVE-2017-0117, CVE-2017-0118, CVE-2017-0119, CVE-2017-0120, CVE-2017-0121, CVE-2017-0122, CVE-2017-0123, CVE-2017-0124, CVE-2017-0125, CVE-2017-0126, CVE-2017-0127, and CVE-2017-0128.

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

 [email protected]
V2 4.3 AV:N/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 : 41646

Publication date : 2017-03-19 23h00 +00:00
Author : Google Security Research
EDB Verified : Yes

Source: https://bugs.chromium.org/p/project-zero/issues/detail?id=1019 We have encountered a crash in the Windows Uniscribe user-mode library, in the usp10!otlChainRuleSetTable::rule function, while trying to display text using a corrupted TTF font file: --- (4464.11b4): Access violation - code c0000005 (first chance) First chance exceptions are reported before any exception handling. This exception may be expected and handled. eax=0933d8bf ebx=00000000 ecx=09340ffc edx=00001b9f esi=0026ecac edi=00000009 eip=752378f3 esp=0026ec24 ebp=0026ec2c iopl=0 nv up ei pl zr na pe nc cs=0023 ss=002b ds=002b es=002b fs=0053 gs=002b efl=00010246 USP10!ScriptPositionSingleGlyph+0x28533: 752378f3 668b4c5002 mov cx,word ptr [eax+edx*2+2] ds:002b:09340fff=???? 0:000> kb ChildEBP RetAddr Args to Child 0026ec2c 752382f3 0026ecac 00001b9f 09340ffc USP10!otlChainRuleSetTable::rule+0x13 0026eccc 75231471 42555347 0026f078 0133d7d2 USP10!otlChainingLookup::apply+0x7d3 0026ed48 752335e1 000000e4 0026f078 0026f09c USP10!ApplyLookup+0x261 0026ef4c 7522f29f 42555347 0026f0b4 0026f078 USP10!ApplyFeatures+0x481 0026ef98 7522f710 00000000 09342ffa 09342f40 USP10!SubstituteOtlGlyphs+0x1bf 0026efd4 752213c0 0026f050 0026f088 0026f0b4 USP10!SubstituteOtlChars+0x220 0026f250 7521548a 0026f35c 0026f388 0026f370 USP10!HebrewEngineGetGlyphs+0x690 0026f310 7521253f 0026f35c 0026f388 0026f370 USP10!ShapingGetGlyphs+0x36a 0026f3fc 751e5c6f 2d011da2 09316124 09316318 USP10!ShlShape+0x2ef 0026f440 751f167a 2d011da2 09316124 09316318 USP10!ScriptShape+0x15f 0026f4a0 751f2b14 00000000 00000000 0026f520 USP10!RenderItemNoFallback+0xfa 0026f4cc 751f2da2 00000000 00000000 0026f520 USP10!RenderItemWithFallback+0x104 0026f4f0 751f4339 00000000 0026f520 09316124 USP10!RenderItem+0x22 0026f534 751e7a04 000004a0 00000400 2d011da2 USP10!ScriptStringAnalyzeGlyphs+0x1e9 0026f54c 76ca5465 2d011da2 09316040 0000000a USP10!ScriptStringAnalyse+0x284 0026f598 76ca5172 2d011da2 0026fa1c 0000000a LPK!LpkStringAnalyse+0xe5 0026f694 76ca1410 2d011da2 00000000 00000000 LPK!LpkCharsetDraw+0x332 0026f6c8 763c18b0 2d011da2 00000000 00000000 LPK!LpkDrawTextEx+0x40 0026f708 763c22bf 2d011da2 00000048 00000000 USER32!DT_DrawStr+0x13c 0026f754 763c21f2 2d011da2 0026fa1c 0026fa30 USER32!DT_GetLineBreak+0x78 0026f800 763c14d4 2d011da2 00000000 0000000a USER32!DrawTextExWorker+0x255 0026f824 763c2475 2d011da2 0026fa1c ffffffff USER32!DrawTextExW+0x1e [...] --- The crash is caused by a single-byte change in a legitimate font file: at offset 0x845A, byte 0x00 is changed to 0xFF. The data region corresponds to the "GSUB" sfnt table. The change causes the otlChainRuleTable::backtrackGlyphCount() function to return an overly large 16-bit integer of 0xED00, which is then used as the number of iterations in a subsequent loop in the otlChainingLookup::apply() function, without prior validation. Increasing (out-of-bounds) indexes are then passed to otlChainRuleSetTable::rule() in the 2nd parameter, and used to address an array of 16-bit indexes. This is where the crash takes place, as the large index eventually starts pointing into the boundary of the last mapped heap memory page. The 16-bit value being read from outside the allocated buffer is later used as yet another index, used to address some an array in the otlChainRuleTable::otlChainRuleTable() routine. While the function only appears to read from the newly formed pointer at first glance, we are not ruling out the possibility of memory corruption. In a read-only scenario, the issue could be potentially used to disclose sensitive data from the process heap. The issue reproduces on Windows 7. It is easiest to reproduce with PageHeap enabled, but it is also possible to observe a crash in a default system configuration. In order to reproduce the problem with the provided samples, it might be necessary to use a custom program which displays all of the font's glyphs at various point sizes. Attached is an archive with the original and modified TTF files. Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/41646.zip

Products Mentioned

Configuraton 0

Microsoft>>Windows_7 >> Version *

Microsoft>>Windows_server_2008 >> Version *

Microsoft>>Windows_server_2008 >> Version r2

Microsoft>>Windows_vista >> Version *

References

https://www.exploit-db.com/exploits/41646/
Tags : exploit, x_refsource_EXPLOIT-DB
http://www.securitytracker.com/id/1037992
Tags : vdb-entry, x_refsource_SECTRACK
http://www.securityfocus.com/bid/96652
Tags : vdb-entry, x_refsource_BID