CVE-2019-9503 : Security Advisory and Response

The Broadcom brcmfmac WiFi driver is vulnerable to a frame validation bypass, potentially allowing attackers to execute arbitrary code or cause denial-of-service conditions.

Understanding CVE-2019-9503

This CVE involves a vulnerability in the Broadcom brcmfmac WiFi driver that allows for a frame validation bypass under specific conditions.

What is CVE-2019-9503?

The vulnerability occurs when the driver receives a firmware event frame from a remote source, potentially leading to the execution of arbitrary code by an unauthenticated attacker.

The Impact of CVE-2019-9503

CVSS Base Score: 7.9 (High)
Attack Vector: Adjacent Network
Attack Complexity: High
Privileges Required: None
User Interaction: Required
Confidentiality, Integrity, and Availability Impact: High
Scope: Changed

Technical Details of CVE-2019-9503

The technical details of the vulnerability provide insights into its description, affected systems, versions, and exploitation mechanism.

Vulnerability Description

The vulnerability allows a frame validation bypass in the Broadcom brcmfmac WiFi driver.
It can be exploited by sending specially-crafted WiFi packets to execute arbitrary code or cause denial-of-service.

Affected Systems and Versions

Affected Product: brcmfmac WiFi driver
Vendor: Broadcom
Vulnerable Version: commit prior to a4176ec356c73a46c07c181c6d04039fafa34a9f

Exploitation Mechanism

The vulnerability can be exploited when the driver receives a firmware event frame from a remote source, bypassing the frame validation mechanism.

Mitigation and Prevention

To address CVE-2019-9503, immediate steps and long-term security practices are essential.

Immediate Steps to Take

Update the Broadcom brcmfmac WiFi driver to the fixed version commit a4176ec356c73a46c07c181c6d04039fafa34a9f.
Monitor network traffic for any signs of exploitation.

Long-Term Security Practices

Regularly update all system components and drivers to prevent known vulnerabilities.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Apply patches provided by Broadcom to address the frame validation bypass vulnerability.