Linux Kernel Remount namespace.c do_remount access control

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CTI Interest Score
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3.6$0-$5k0.00

Summaryinfo

A vulnerability described as problematic has been identified in Linux Kernel. This affects the function do_remount of the file namespace.c of the component Remount Handler. Executing a manipulation can lead to access control. This vulnerability is handled as CVE-2014-5207. Additionally, an exploit exists. It is best practice to apply a patch to resolve this issue.

Detailsinfo

A vulnerability classified as problematic was found in Linux Kernel (Operating System) (unknown version). This vulnerability affects the function do_remount of the file namespace.c of the component Remount Handler. The manipulation with an unknown input leads to a access control vulnerability. The CWE definition for the vulnerability is CWE-264. As an impact it is known to affect integrity.

The weakness was released 08/13/2014 by Kenton Varda as mnt: Correct permission checks in do_remount as confirmed git commit (GIT Repository). The advisory is available at git.kernel.org. This vulnerability was named CVE-2014-5207 since 08/13/2014. The exploitation appears to be easy. Local access is required to approach this attack. No form of authentication is required for a successful exploitation. Technical details and also a public exploit are known. This vulnerability is assigned to T1068 by the MITRE ATT&CK project. Responsible for the vulnerability is the following code: 

if ((flag & CL_UNPRIVILEGED) && (mnt->mnt.mnt_flags & MNT_READONLY))
   		mnt->mnt.mnt_flags |= MNT_LOCK_READONLY;
The advisory points out:
While invesgiating the issue where in "mount --bind -oremount,ro ..." would result in later "mount --bind -oremount,rw" succeeding even if the mount started off locked I realized that there are several additional mount flags that should be locked and are not.

A public exploit has been developed by Andy Lutomirski in ANSI C and been published 3 months after the advisory. It is possible to download the exploit at securityfocus.com. It is declared as proof-of-concept. The vulnerability scanner Nessus provides a plugin with the ID 78360 (Amazon Linux AMI : kernel (ALAS-2014-417)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Amazon Linux Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157067 (Oracle Enterprise Linux Security Update for Unbreakable Enterprise kernel (ELSA-2015-3012)).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org.

The vulnerability is also documented in the databases at X-Force (95266), Exploit-DB (34923), Tenable (78360), SecurityFocus (BID 69216†) and OSVDB (110055†). Additional details are provided at seclists.org. Entries connected to this vulnerability are available at VDB-67365, VDB-69019 and VDB-69020. Once again VulDB remains the best source for vulnerability data.

Productinfo

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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

AVACAuCIA
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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
Author: Andy Lutomirski
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 78360
Nessus Name: Amazon Linux AMI : kernel (ALAS-2014-417)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍

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

Qualys ID: 🔍
Qualys Name: 🔍

Exploit-DB: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍
Exploit Delay Time: 🔍

Patch: 9566d6742852c527bf5af38af5cbb878dad75705
McAfee IPS: 🔍
McAfee IPS Version: 🔍

Timelineinfo

08/13/2014 🔍
08/13/2014 +0 days 🔍
08/13/2014 +0 days 🔍
08/13/2014 +0 days 🔍
08/14/2014 +1 days 🔍
08/14/2014 +0 days 🔍
08/18/2014 +4 days 🔍
10/09/2014 +52 days 🔍
10/09/2014 +0 days 🔍
11/25/2024 +3700 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: mnt: Correct permission checks in do_remount
Researcher: Kenton Varda
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2014-5207 (🔍)
GCVE (CVE): GCVE-0-2014-5207
GCVE (VulDB): GCVE-100-67366

OVAL: 🔍

X-Force: 95266 - Linux Kernel do_remount security bypass, Low Risk
SecurityFocus: 69216 - Linux Kernel CVE-2014-5207 Local Security Bypass Vulnerability
OSVDB: 110055
Vulnerability Center: 45836 - Linux Kernel Local Security Bypass Vulnerability via Remounting a Read Only Mount - CVE-2014-5207, Low

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

Entryinfo

Created: 08/14/2014 12:19
Updated: 11/25/2024 15:30
Changes: 08/14/2014 12:19 (81), 06/04/2017 10:48 (14), 02/10/2022 18:57 (4), 02/10/2022 19:05 (1), 11/25/2024 15:30 (18)
Complete: 🔍
Cache ID: 216:694:103

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