CVE-2016-6914 : Detail

CVE-2016-6914

7.8
/
High
A01-Broken Access Control
0.08%V3
Local
2017-12-27
16h00 +00:00
2017-12-28
09h57 +00:00
CVE.org
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CVE Descriptions

Ubiquiti UniFi Video before 3.8.0 for Windows uses weak permissions for the installation directory, which allows local users to gain SYSTEM privileges via a Trojan horse taskkill.exe file.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-276 Incorrect Default Permissions
During installation, installed file permissions are set to allow anyone to modify those files.

Metrics

Metrics Score Severity CVSS Vector Source
V3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/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.

Local

The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities.

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 when attacking the vulnerable component.

Privileges Required

This metric describes the level of privileges an attacker must possess before successfully exploiting the vulnerability.

Low

The attacker 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 has the ability to access only non-sensitive resources.

User Interaction

This metric captures the requirement for a human user, other than the attacker, to participate in the successful compromise of the vulnerable component.

None

The vulnerable system can be exploited without interaction from any user.

Base: Scope Metrics

The Scope metric captures whether a vulnerability in one vulnerable component impacts resources in components beyond its security scope.

Scope

Formally, a security authority is a mechanism (e.g., an application, an operating system, firmware, a sandbox environment) that defines and enforces access control in terms of how certain subjects/actors (e.g., human users, processes) can access certain restricted objects/resources (e.g., files, CPU, memory) in a controlled manner. All the subjects and objects under the jurisdiction of a single security authority are considered to be under one security scope. If a vulnerability in a vulnerable component can affect a component which is in a different security scope than the vulnerable component, a Scope change occurs. Intuitively, whenever the impact of a vulnerability breaches a security/trust boundary and impacts components outside the security scope in which vulnerable component resides, a Scope change occurs.

Unchanged

An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.

Base: Impact Metrics

The Impact metrics capture the effects of a successfully exploited vulnerability on the component that suffers the worst outcome that is most directly and predictably associated with the attack. Analysts should constrain impacts to a reasonable, final outcome which they are confident an attacker is able to achieve.

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 a 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 a 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 in the description of a vulnerability.

Environmental Metrics

These metrics enable the analyst to customize the CVSS score depending on the importance of the affected IT asset to a user’s organization, measured in terms of Confidentiality, Integrity, and Availability.

 [email protected]
V2 7.2 AV:L/AC:L/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 : 43390

Publication date : 2017-12-25 23h00 +00:00
Author : Julien Ahrens
EDB Verified : No

RCE Security Advisory https://www.rcesecurity.com 1. ADVISORY INFORMATION ======================= Product: Ubiquiti UniFi Video (Windows) Vendor URL: https://www.ubnt.com Type: Improper Handling of Insufficient Permissions or Privileges [CWE-280] Date found: 2016-05-24 Date published: 2017-12-20 CVSSv3 Score: 7.8 (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) CVE: CVE-2016-6914 2. CREDITS ========== This vulnerability was discovered and researched by Julien Ahrens from RCE Security. 3. VERSIONS AFFECTED ==================== UniFi Video 3.7.3 (Windows), UniFi Video 3.7.0 (Windows), UniFi Video 3.2.2 (Windows), older versions may be affected too. 4. INTRODUCTION =============== UniFi Video is a powerful and flexible, integrated IP video management surveillance system designed to work with Ubiquiti’s UniFi Video Camera product line. UniFi Video has an intuitive, configurable, and feature‑packed user interface with advanced features such as motion detection, auto‑discovery, user-level security, storage management, reporting, and mobile device support. (from the vendor's homepage) 5. VULNERABILITY DETAILS ======================== Ubiquiti UniFi Video for Windows is installed to "C:\ProgramData\unifi-video\" by default and is also shipped with a service called "Ubiquiti UniFi Video". Its executable "avService.exe" is placed in the same directory and also runs under the NT AUTHORITY/SYSTEM account. However the default permissions on the "C:\ProgramData\unifi-video" folder are inherited from "C:\ProgramData" and are not explicitly overridden, which allows all users, even unprivileged ones, to append and write files to the application directory: c:\ProgramData>icacls unifi-video unifi-video NT AUTHORITY\SYSTEM:(I)(OI)(CI)(F) BUILTIN\Administrators:(I)(OI)(CI)(F) CREATOR OWNER:(I)(OI)(CI)(IO)(F) BUILTIN\Users:(I)(OI)(CI)(RX) BUILTIN\Users:(I)(CI)(WD,AD,WEA,WA) Upon start and stop of the service, it tries to load and execute the file at "C:\ProgramData\unifi-video\taskkill.exe". However this file does not exist in the application directory by default at all. By copying an arbitrary "taskkill.exe" to "C:\ProgramData\unifi-video\" as an unprivileged user, it is therefore possible to escalate privileges and execute arbitrary code as NT AUTHORITY/SYSTEM. 6. RISK ======= To successfully exploit this vulnerability, an attacker must already have access to a system running a vulnerable installation of UniFi video using a low-privileged user account (i.e. through a password compromise). The vulnerability allows local attackers to escalate privileges and execute arbitrary code as NT AUTHORITY/SYSTEM, which basically means a complete loss of the system's confidentiality, integrity as well as availability. 7. SOLUTION =========== Update to v3.8.0 8. REPORT TIMELINE ================== 2016-05-24: Discovery of the vulnerability 2016-05-24: Reported to vendor via HackerOne (#140793) 2016-05-24: Vendor acknowledges the vulnerability 2016-08-22: Request for status update 2016-08-22: Vendor states that there is no update so far 2016-08-23: MITRE assigns CVE-2016-6914 2016-11-08: Request for status update 2016-11-08: Vendor states that there is no update so far 2016-12-08: Request for status update 2016-12-08: Vendor states that project team is working on it 2017-02-23: Request for status update 2017-03-23: No response from vendor 2017-03-23: Request for status update 2017-03-23: Vendor states that fix is scheduled for v3.7.0 2017-05-23: v3.7.0 was released, but vulnerability is still exploitable, vendor notified again 2017-06-07: Vendor states that fix is actually delayed 2017-08-26: Vendor provides beta versions of 3.7.3 and 3.8.0-beta3, which should fix the issue 2017-08-31: While v3.7.3 is still vulnerable, the issue was fixed in 3.8.0-beta3 2017-09-18: v3.8.0 released publicly 2017-12-20: Public disclosure 9. REFERENCES ============= http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=2016-6914 https://hackerone.com/reports/140793

Products Mentioned

Configuraton 0

Ui>>Unifi_video >> Version To (excluding) 3.8.0

Microsoft>>Windows >> Version *

References

http://www.securityfocus.com/bid/102278
Tags : vdb-entry, x_refsource_BID
http://seclists.org/fulldisclosure/2017/Dec/83
Tags : mailing-list, x_refsource_FULLDISC
https://www.exploit-db.com/exploits/43390/
Tags : exploit, x_refsource_EXPLOIT-DB