Linux Kernel Remount access control

CVSS Meta Temp Score
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CTI Interest Score
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3.6$0-$5k0.00

Summaryinfo

A vulnerability marked as problematic has been reported in Linux Kernel. Affected by this issue is some unknown functionality of the component Remount Handler. Performing a manipulation results in access control. This vulnerability is known as CVE-2014-5206. Furthermore, an exploit is available. Applying a patch is the recommended action to fix this issue.

Detailsinfo

A vulnerability classified as problematic has been found in Linux Kernel (Operating System) (the affected version is unknown). This affects an unknown code of the component Remount Handler. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-264. This is going to have an impact on integrity.

The weakness was published 08/12/2014 by Kenton Varda as mnt: Add tests for unprivileged remount cases that have found to be faulty as confirmed git commit (GIT Repository). The advisory is shared at git.kernel.org. This vulnerability is uniquely identified as CVE-2014-5206 since 08/13/2014. The exploitability is told to be easy. An attack has to be approached locally. No form of authentication is needed for exploitation. Technical details are unknown but a public exploit is available. MITRE ATT&CK project uses the attack technique T1068 for this issue. The advisory points out:

Due to a bug in the Linux kernel's implementation of remount, on systems with unprivileged user namespaces enabled, it is possible for an unprivileged user to gain write access to any visible read-only bind mount. It is also possible to bypass flags like nodev, nosuid, and noexec.

A public exploit has been developed in ANSI C and been published immediately after the advisory. The exploit is shared for download at git.kernel.org. It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 77237 (Ubuntu 14.04 LTS : linux vulnerabilities (USN-2318-1)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Ubuntu Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 350312 (Amazon Linux Security Advisory for kernel: ALAS-2014-417).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The git commit contains the following remark:

The first naive patch to fix these issues contained the flaw that using default atime settings when remounting a filesystem could be disallowed.

The vulnerability is also documented in the databases at X-Force (95265), Tenable (77237), SecurityFocus (BID 69214†) and Vulnerability Center (SBV-45829†). Further details are available at seclists.org. Similar entry is available at VDB-67366. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.0
VulDB Meta Temp Score: 3.6

VulDB Base Score: 4.0
VulDB Temp Score: 3.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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Exploitinginfo

Class: Access control
CWE: CWE-264
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
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Nessus ID: 77237
Nessus Name: Ubuntu 14.04 LTS : linux vulnerabilities (USN-2318-1)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Port: 🔍

OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: ALAS-2014-417
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍
Exploit Delay Time: 🔍

Patch: a6138db815df5ee542d848318e5dae681590fccd

Timelineinfo

08/01/2014 🔍
08/12/2014 +11 days 🔍
08/12/2014 +0 days 🔍
08/13/2014 +1 days 🔍
08/13/2014 +0 days 🔍
08/14/2014 +1 days 🔍
08/14/2014 +0 days 🔍
08/18/2014 +4 days 🔍
08/18/2014 +0 days 🔍
02/10/2022 +2733 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: mnt: Add tests for unprivileged remount cases that have found to be faulty
Researcher: Kenton Varda
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-5206 (🔍)
GCVE (CVE): GCVE-0-2014-5206
GCVE (VulDB): GCVE-100-67365

OVAL: 🔍

X-Force: 95265 - Linux Kernel remount security bypass, Low Risk
SecurityFocus: 69214 - Linux Kernel CVE-2014-5206 Local Security Bypass Vulnerability
Vulnerability Center: 45829 - Linux Kernel Local Security Bypass Vulnerability via Remounting a Read Only Mount - CVE-2014-5206, Medium

scip Labs: https://www.scip.ch/en/?labs.20161013
Misc.: 🔍
See also: 🔍

Entryinfo

Created: 08/14/2014 12:17
Updated: 02/10/2022 18:50
Changes: 08/14/2014 12:17 (81), 06/04/2017 10:48 (7), 02/10/2022 18:43 (4), 02/10/2022 18:50 (1)
Complete: 🔍
Cache ID: 216:89B:103

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