PT-2021-4358 · Cypress · Cypress Wiced Bt Stack

Published 2021-09-07 · Updated 2021-09-14 · CVE-2021-34148

Positive Technologies (AI Summary)

CVSS v3.1

6.5

Medium

Base vector

AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Cypress WICED BT stack versions through 2.9.0 for CYW20735B1 devices

Description The Bluetooth Classic implementation in the Cypress WICED BT stack does not properly handle the reception of LMP max slot with a greater ACL Length after completion of the LMP setup procedure. This allows attackers in radio range to trigger a denial of service (firmware crash) via a crafted LMP packet. The issue exists due to insufficient input validation, which can be exploited by a remote attacker to cause a denial of service.

Recommendations For versions through 2.9.0, consider disabling the Bluetooth Classic implementation until a patch is available to prevent potential denial of service attacks. Restrict access to the LMP setup procedure to minimize the risk of exploitation. Avoid using the LMP max slot parameter with a greater ACL Length after completion of the LMP setup procedure until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

RCE

Weakness Enumeration

CWE-20

Related Identifiers

BDU:2021-04987

CVE-2021-34148

Affected Products

Cypress Wiced Bt Stack

References · 14

• https://ubuntu.com/security/CVE-2021-34148 · Vendor Advisory
• https://cypress.com/documentation/datasheets/cyw20735b1-single-chip-bluetooth-transceiver-wireless-input-devices · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-34148 · Vendor Advisory
• https://bdu.fstec.ru/vul/2021-04987 · Security Note
• https://osv.dev/vulnerability/CVE-2021-34148 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-34148 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-34148 · Security Note
• https://cve.org/CVERecord?id=CVE-2021-34148 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2021-34148 · Vendor Advisory
• https://github.com/RPi-Distro/bluez-firmware/commit/31ad68831357d2019624004f1f0846475671088f · Note
• https://t.me/cvenotify/20837 · Telegram Post
• https://cybersecurity-help.cz/vdb/SB2021090612 · Note
• https://t.me/cibsecurity/28313 · Telegram Post
• https://dl.packetstormsecurity.net/papers/general/braktooth.pdf · Note