CVE-2018-8468 : Detail

CVE-2018-8468

4.7
/
Medium
1.27%V3
Network
2018-09-12
22h00 +00:00
2018-09-29
07h57 +00:00
CVE.org
NVD
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CVE Descriptions

An elevation of privilege vulnerability exists when Windows, allowing a sandbox escape, aka "Windows Elevation of Privilege 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.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE Other No informations.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 4.7 MEDIUM CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/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.

Changed

An exploited vulnerability can affect resources beyond the authorization privileges intended by the vulnerable component. In this case the vulnerable component and the impacted component are different.

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.

None

There is no loss of confidentiality within 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.

Low

Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is constrained. The data modification does not have a direct, serious impact on 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:N/I:P/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 : 45502

Publication date : 2018-09-26 22h00 +00:00
Author : Google Security Research
EDB Verified : Yes

1. Content process -> Privileged content process (first_stage.js) When spawning a new Edge content process, its privilege is determined by its URL. This URL check is performed by the LCIEUrlPolicy::GetPICForPrivilegedInternalPage method in eModel.dll. The method calls several another methods to check the URL. One of them EdgeUrlUtils::IsAboutFlagsResUri is vulnerable. Since it only checks the scheme and whether the URL ends with "/edgehtml.dll/flags.htm", the following URL which will execute arbitrary JavaScript code will be considered to need to spawn a privileged content process. res://apds.dll/redirect.html?target=javascript:alert(1)//edgehtml.dll/flags.htm As a navigation triggered from JavaScript to the "res" scheme is not allowed, an additional renderer exploit is required. I used issue 1588 for it. 2. Privileged content process -> Internet Explorer (second_stage.js) In a privileged content process, we can ask to the host to launch IE for some sites for compatibility. The host then redirects the request to the broker after checking whether the domain of the requested URL is in the IE compatibility view list. Since it only checks the domain, an arbitrary scheme like "file://" can be given. For this part, a domain in the IE compatibility view list is required to host a samba server. I found that some domains were unregistered, but I just modified the hosts file for testing. 3. Internet Explorer If the given URL has the "file://" scheme and it's a folder, IE will just open it using ShellExecuteExW. I managed to create a lnk file that bypasses the folder check and executes an arbitrary file. Please find lnk_bug.cc in the PoC. To reproduce the PoC, you will need a remote machine hosting a samba server and a http server. Note that the PoC uses hardcoded offsets for "Build 17692.rs_prerelease.180609-1317". Proof of Concept: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/45502.zip

Products Mentioned

Configuraton 0

Microsoft>>Windows_10 >> Version -

Microsoft>>Windows_10 >> Version 1607

Microsoft>>Windows_10 >> Version 1703

Microsoft>>Windows_10 >> Version 1709

Microsoft>>Windows_10 >> Version 1803

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 -

Microsoft>>Windows_server_2016 >> Version 1709

Microsoft>>Windows_server_2016 >> Version 1803

References

http://www.securityfocus.com/bid/105275
Tags : vdb-entry, x_refsource_BID
https://www.exploit-db.com/exploits/45502/
Tags : exploit, x_refsource_EXPLOIT-DB