CVE-2020-12351
Description
A flaw was found in the way the Linux kernel’s Bluetooth implementation handled L2CAP (Logical Link Control and Adaptation Protocol) packets with A2MP (Alternate MAC-PHY Manager Protocol) CID (Channel Identifier). This flaw allows a remote attacker in an adjacent range to crash the system, causing a denial of service or potentially executing arbitrary code on the system by sending a specially crafted L2CAP packet. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Security Bulletin
Statement
Red Hat Enterprise Linux 7 is affected starting with the Red Hat Enterprise Linux 7.4 GA kernel version 3.10.0-693 onward.
For Red Hat OpenShift Container Platform, while the cluster nodes may be running an underlying kernel that's affected by this flaw present, both virtual and physical hosts in a production environment will generally have the mitigation already in place of having Bluetooth hardware either not present, or not enabled.
Mitigation
To mitigate these vulnerabilities on the operating system level, disable the Bluetooth functionality via blocklisting kernel modules in the Linux kernel. The kernel modules can be prevented from being loaded by using system-wide modprobe rules. Instructions on how to disable Bluetooth modules are available on the Customer Portal at https://access.redhat.com/solutions/2682931.
Alternatively, Bluetooth can be disabled within the hardware or at BIOS level which will also provide an effective mitigation as the kernel will not be able to detect that Bluetooth hardware is present on the system.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.8 | 8.8 | N/A |
| Attack Vector | Adjacent Network | Adjacent Network | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability,Integrity,Confidentiality
Technical Impact: Read Memory; Modify Memory; Execute Unauthorized Code or Commands; DoS: Crash, Exit, or Restart
When a memory buffer is accessed using the wrong type, it could read or write memory out of the bounds of the buffer, if the allocated buffer is smaller than the type that the code is attempting to access, leading to a crash and possibly code execution.
Acknowledgements
Red Hat would like to thank Andy Nguyen (Google) and Intel for reporting this issue.
Frequently Asked Questions
Not sure what something means? Check out our Security Glossary.
Want to get errata notifications? Sign up here.
