CVE-2020-26555
Description
A vulnerability was found in Linux Kernel, where Bluetooth BR/EDR PIN Pairing procedure is vulnerable to an impersonation attack. When an attacker connects to a victim device using the address of the device and the victim initiates a Pairing, the attacker can reflect the encrypted nonce even without knowledge of the key.
Statement
Red Hat Product Security is aware of this issue and is currently assessing the impact on Red Hat supported products. Corresponding entry in the Red Hat CVE database (https://access.redhat.com/security/security-updates/#/cve) will be updated with latest information as the assessment progresses.
Mitigation
It is recommended that devices not accept connections from or initiate connections to remote devices claiming the same Bluetooth device address as their own, also a controller computing a null (zero-valued) combination not accept this key as a valid and fail any pairing attempt that produced a null key.
It is also recommends that BR/EDR implementations enable Secure Simple Pairing, and where possible, implementations enable and enforce Secure Connections Only Mode, ensuring that pin-code pairing cannot be used.
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 | 5.4 | 5.4 | 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 | Low | Low | N/A |
| Integrity Impact | Low | Low | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an attacker can trigger the allocation of the limited resources, but the number or size of the resources is not controlled, then the most common result is denial of service. This would prevent valid users from accessing the product, and it could potentially have an impact on the surrounding environment, i.e., the product may slow down, crash due to unhandled errors, or lock out legitimate users. For example, a memory exhaustion attack against an application could slow down the application as well as its host operating system.
Access Control,Other
Technical Impact: Bypass Protection Mechanism; Other
In some cases it may be possible to force the product to "fail open" in the event of resource exhaustion. The state of the product -- and possibly the security functionality - may then be compromised.
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