Linux Kernel up to 4.6.3 nfsd nfs4acl.c nfsacld_proc_setacl access control

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
7.5$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Linux Kernel up to 4.6.3. This impacts the function nfsacld_proc_setacl of the file nfs2acl.c/nfs3acl.c/nfs4acl.c of the component nfsd. Performing a manipulation results in access control. This vulnerability was named CVE-2016-1237. The attack may be initiated remotely. There is no available exploit. It is recommended to apply a patch to fix this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 4.6.3 (Operating System). This affects the function nfsacld_proc_setacl of the file nfs2acl.c/nfs3acl.c/nfs4acl.c of the component nfsd. The manipulation with an unknown input leads to a access control vulnerability. CWE is classifying the issue as CWE-284. The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

nfsd in the Linux kernel through 4.6.3 allows local users to bypass intended file-permission restrictions by setting a POSIX ACL, related to nfs2acl.c, nfs3acl.c, and nfs4acl.c.

The weakness was presented 06/29/2016 (oss-sec). It is possible to read the advisory at openwall.com. This vulnerability is uniquely identified as CVE-2016-1237 since 12/27/2015. The exploitability is told to be easy. Attacking locally is a requirement. The successful exploitation needs a authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1068 according to MITRE ATT&CK. The reason for this vulnerability is this part of code: 

error = inode->i_op->set_acl(inode, argp->acl_access, ACL_TYPE_ACCESS);

The vulnerability scanner Nessus provides a plugin with the ID 91886 (Debian DSA-3607-1 : linux - security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 175775 (Debian Security Update for linux (DSA 3607-1)).

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com. A possible mitigation has been published even before and not after the disclosure of the vulnerability. The vulnerability will be addressed with the following lines of code:

error = set_posix_acl(inode, ACL_TYPE_ACCESS, argp->acl_access);

The vulnerability is also documented in the databases at Tenable (91886) and SecurityFocus (BID 91456†). See VDB-88380 and VDB-88379 for similar entries. Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.7
VulDB Meta Temp Score: 7.5

VulDB Base Score: 9.8
VulDB Temp Score: 9.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.5
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock
UnlockUnlockUnlockUnlockUnlockUnlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-284 / CWE-266
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: Yes

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-DayUnlockUnlockUnlockUnlock
TodayUnlockUnlockUnlockUnlock

Nessus ID: 91886
Nessus Name: Debian DSA-3607-1 : linux - security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 53829
OpenVAS Name: Ubuntu Update for linux-snapdragon USN-3070-3
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔍

Patch: github.com

Timelineinfo

12/27/2015 🔍
06/22/2016 +178 days 🔍
06/25/2016 +3 days 🔍
06/29/2016 +4 days 🔍
06/29/2016 +0 days 🔍
06/29/2016 +0 days 🔍
06/30/2016 +1 days 🔍
08/25/2022 +2247 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: USN-3053-1
Status: Not defined
Confirmation: 🔍

CVE: CVE-2016-1237 (🔍)
GCVE (CVE): GCVE-0-2016-1237
GCVE (VulDB): GCVE-100-88383

OVAL: 🔍

SecurityFocus: 91456 - Linux Kernel CVE-2016-1237 Security Bypass Vulnerability

See also: 🔍

Entryinfo

Created: 06/30/2016 09:26
Updated: 08/25/2022 13:43
Changes: 06/30/2016 09:26 (56), 02/12/2019 11:02 (19), 08/25/2022 13:38 (2), 08/25/2022 13:43 (11)
Complete: 🔍
Cache ID: 216:88A:103

Discussion

No comments yet. Languages: en.

Please log in to comment.

◂ PreviousOverviewNext ▸

Do you know our Splunk app?

Download it now for free!