CVE-2016-9950 : Detail

CVE-2016-9950

7.8
/
High
Directory Traversal
A01-Broken Access Control
0.14%V3
Local
2016-12-17
02h34 +00:00
2017-01-04
13h57 +00:00
CVE.org
NVD
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CVE Descriptions

An issue was discovered in Apport before 2.20.4. There is a path traversal issue in the Apport crash file "Package" and "SourcePackage" fields. These fields are used to build a path to the package specific hook files in the /usr/share/apport/package-hooks/ directory. An attacker can exploit this path traversal to execute arbitrary Python files from the local system.

CVE Informations

Related Weaknesses

CWE-ID Weakness Name Source
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Metrics

Metrics Score Severity CVSS Vector Source
V3.0 7.8 HIGH CVSS:3.0/AV:L/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.

Local

A vulnerability exploitable with Local access means that the vulnerable component is not bound to the network stack, and the attacker's path is via read/write/execute capabilities. In some cases, the attacker may be logged in locally in order to exploit the vulnerability, otherwise, she may rely on User Interaction to execute a malicious file.

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 : 40937

Publication date : 2016-12-13
23h00 +00:00
Author : Donncha OCearbhaill
EDB Verified : No

Both of these issues were reported to the Apport maintainers and a fix was released on 2016-12-14. The CrashDB code injection issue can be tracked with CVE-2016-9949 and the path traversal bug with CVE-2016-9950. An additional problem where arbitrary commands can be called with the “Relaunch” action is tracked by CVE-2016-9951. I’d like to thank Martin Pitt and the Ubuntu security team for getting a fix (https://bugs.launchpad.net/apport/+bug/1648806) released so quickly. They have been a pleasure to work with. I would encourage all security researchers to audit free and open source software if they have time on their hands. Projects such as Tor, Tails, Debian and Ubuntu all need more eyes for audits which can improve the safety of the internet for everyone. There are lots of bugs out there which don’t need hardcore memory corruption exploitation skills. Logic bugs can be much more reliable than any ROP chain. The computer security industry has a serious conflict of interest right now. There is major financial motivation for researchers to find and disclose vulnerability to exploit brokers. Many of the brokers are in the business of keeping problems unfixed. Code execution bugs are valuable. As a data point, I received an offer of more than 10,000 USD from an exploit vendor for these Apport bugs. These financial motivators are only increasing as software gets more secure and bugs become more difficult to find. To improve security for everyone we need to find sustainable ways to incentivize researchers to find and disclose issues and to get bugs fixed. We can’t and we shouldn’t rely on researchers giving away their work for free to for-profit vendors. We will not get security like that. Microsoft and Google have shown a good example with their vulnerability reward programs. The Internet Bug Bounty (https://internetbugbounty.org/) is also doing great work and helping to support research on critical internet software. I hope that they can continue the program and expand their scope in the future. I hope we can cooperatively build a shared and secure internet together. Source: https://donncha.is/2016/12/compromising-ubuntu-desktop/ Download: https://github.com/DonnchaC/ubuntu-apport-exploitation/archive/6ecfdf798f39fdd49b5929240d90a876c1e97ebb.zip Mirror: https://gitlab.com/exploit-database/exploitdb-bin-sploits/-/raw/main/bin-sploits/40937.zip

Products Mentioned

Configuraton 0

Apport_project>>Apport >> Version To (including) 2.20.3

Configuraton 0

Canonical>>Ubuntu_linux >> Version To (including) 12.10

References

http://www.securityfocus.com/bid/95011
Tags : vdb-entry, x_refsource_BID
http://www.ubuntu.com/usn/USN-3157-1
Tags : vendor-advisory, x_refsource_UBUNTU
https://www.exploit-db.com/exploits/40937/
Tags : exploit, x_refsource_EXPLOIT-DB