Linux Kernel up to 4.6.3 security/keys/key.c key_reject_and_link use after free
| CVSS Meta Temp Score | Current Exploit Price (≈) | CTI Interest Score |
|---|---|---|
| 5.2 | $0-$5k | 0.00 |
Summary
A vulnerability was found in Linux Kernel up to 4.6.3. It has been declared as problematic. Affected by this vulnerability is the function key_reject_and_link of the file security/keys/key.c. The manipulation results in use after free.
This vulnerability is cataloged as CVE-2016-4470. The attack must be initiated from a local position. Furthermore, there is an exploit available.
It is best practice to apply a patch to resolve this issue.
Details
A vulnerability, which was classified as problematic, was found in Linux Kernel up to 4.6.3 (Operating System). Affected is the function key_reject_and_link of the file security/keys/key.c. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on availability. CVE summarizes:
The key_reject_and_link function in security/keys/key.c in the Linux kernel through 4.6.3 does not ensure that a certain data structure is initialized, which allows local users to cause a denial of service (system crash) via vectors involving a crafted keyctl request2 command.
The weakness was shared 06/15/2016 (oss-sec). The advisory is available at openwall.com. This vulnerability is traded as CVE-2016-4470 since 05/02/2016. The exploitability is told to be easy. Local access is required to approach this attack. Required for exploitation is a authentication. Technical details and a public exploit are known. The reason for this vulnerability is this part of code:
if (keyring)
A public exploit has been developed in Bash. 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 92232 (Fedora 24 : kernel (2016-1c409313f4)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Fedora Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157314 (Oracle Enterprise Linux Security Update for kernel (ELSA-2016-2574)-Deprecated). The advisory illustrates:
The bug can be triggered using option (3) above using something like the following: echo 80 >/proc/sys/kernel/keys/root_maxbytes; keyctl request2 user debug:fred negate @t
Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. A possible mitigation has been published 2 days after the disclosure of the vulnerability. The vulnerability will be addressed with the following lines of code:
if (keyring && link_ret == 0)
The vulnerability is also documented in the databases at Tenable (92232) and SecurityFocus (BID 76005†). The entries VDB-77497, VDB-79923, VDB-82951 and VDB-82953 are related to this item. VulDB is the best source for vulnerability data and more expert information about this specific topic.
Product
Type
Vendor
Name
Version
License
Website
- Vendor: https://www.kernel.org/
CPE 2.3
CPE 2.2
CVSSv4
VulDB Vector: 🔍VulDB Reliability: 🔍
CVSSv3
VulDB Meta Base Score: 5.5VulDB Meta Temp Score: 5.2
VulDB Base Score: 5.5
VulDB Temp Score: 5.0
VulDB Vector: 🔍
VulDB Reliability: 🔍
NVD Base Score: 5.5
NVD Vector: 🔍
CVSSv2
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍
NVD Base Score: 🔍
Exploiting
Class: Use after freeCWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍
Physical: Partially
Local: Yes
Remote: No
Availability: 🔍
Access: Public
Status: Proof-of-Concept
Programming Language: 🔍
Download: 🔍
EPSS Score: 🔍
EPSS Percentile: 🔍
Price Prediction: 🔍
Current Price Estimation: 🔍
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| Today | Unlock | Unlock | Unlock | Unlock |
Nessus ID: 92232
Nessus Name: Fedora 24 : kernel (2016-1c409313f4)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
OpenVAS ID: 14611
OpenVAS Name: Amazon Linux Local Check: alas-2016-726
OpenVAS File: 🔍
OpenVAS Family: 🔍
Qualys ID: 🔍
Qualys Name: 🔍
Threat Intelligence
Interest: 🔍Active Actors: 🔍
Active APT Groups: 🔍
Countermeasures
Recommended: PatchStatus: 🔍
Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Patch: git.kernel.org
Timeline
05/02/2016 🔍06/15/2016 🔍
06/17/2016 🔍
06/27/2016 🔍
06/29/2016 🔍
07/15/2016 🔍
08/25/2022 🔍
Sources
Vendor: kernel.orgAdvisory: FEDORA-2016-1c409313f4
Status: Confirmed
Confirmation: 🔍
CVE: CVE-2016-4470 (🔍)
GCVE (CVE): GCVE-0-2016-4470
GCVE (VulDB): GCVE-100-88374
OVAL: 🔍
SecurityFocus: 76005
SecurityTracker: 1036763
scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍
Entry
Created: 06/29/2016 11:21Updated: 08/25/2022 12:27
Changes: 06/29/2016 11:21 (72), 02/12/2019 10:35 (15), 08/25/2022 12:13 (5), 08/25/2022 12:20 (1), 08/25/2022 12:27 (1)
Complete: 🔍
Cache ID: 216:6BC:103
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