CVE-2019-9500 : What You Need to Know

The Broadcom brcmfmac WiFi driver is vulnerable to a heap buffer overflow, allowing attackers to compromise the host or execute arbitrary code on a vulnerable system.

Understanding CVE-2019-9500

This CVE describes a critical vulnerability in the Broadcom brcmfmac WiFi driver that can lead to denial-of-service situations and remote code execution.

What is CVE-2019-9500?

The vulnerability in the Broadcom brcmfmac WiFi driver allows for a heap buffer overflow, triggered when the Wake-up on Wireless LAN functionality is configured. This overflow occurs in versions prior to commit 1b5e2423164b3670e8bc9174e4762d297990deff.

The Impact of CVE-2019-9500

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

Technical Details of CVE-2019-9500

The technical details of this CVE provide insight into the vulnerability's specifics.

Vulnerability Description

The vulnerability is a heap-based buffer overflow (CWE-122) in the brcmf_wowl_nd_results function of the Broadcom brcmfmac WiFi driver.

Affected Systems and Versions

Product: brcmfmac WiFi driver
Vendor: Broadcom
Vulnerable Version: commit prior to 1b5e2423164b3670e8bc9174e4762d297990deff

Exploitation Mechanism

Attackers can create a malicious event frame to trigger the heap buffer overflow when Wake-up on Wireless LAN is configured.
Compromised chipsets can exploit this vulnerability to compromise the host.
When combined with CVE-2019-9503, remote exploitation is possible.
Remote, unauthenticated attackers can execute arbitrary code by sending specially-crafted WiFi packets.

Mitigation and Prevention

Protecting systems from CVE-2019-9500 requires immediate action and long-term security practices.

Immediate Steps to Take

Apply the patch provided by Broadcom to address the vulnerability.
Disable the Wake-up on Wireless LAN functionality if not essential.
Monitor network traffic for any signs of exploitation.

Long-Term Security Practices

Regularly update and patch all software and firmware to prevent vulnerabilities.
Implement network segmentation and access controls to limit the impact of potential attacks.

Patching and Updates

Patch available at: https://git.kernel.org/linus/1b5e2423164b3670e8bc9174e4762d297990deff