Broadcom brcmfmac WiFi Driver Frame Validation is_wlc_event_frame WiFi Packet input validation

Summaryinfo

A vulnerability, which was classified as critical, was found in Broadcom brcmfmac WiFi Driver. Impacted is the function is_wlc_event_frame of the component Frame Validation Handler. The manipulation as part of WiFi Packet results in input validation. This vulnerability was named CVE-2019-9503. The attack needs to be approached within the local network. There is no available exploit. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability, which was classified as critical, was found in Broadcom brcmfmac WiFi Driver (Hardware Driver Software) (affected version not known). Affected is the function is_wlc_event_frame of the component Frame Validation Handler. The manipulation as part of a WiFi Packet leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

The Broadcom brcmfmac WiFi driver prior to commit a4176ec356c73a46c07c181c6d04039fafa34a9f is vulnerable to a frame validation bypass. If the brcmfmac driver receives a firmware event frame from a remote source, the is_wlc_event_frame function will cause this frame to be discarded and unprocessed. If the driver receives the firmware event frame from the host, the appropriate handler is called. This frame validation can be bypassed if the bus used is USB (for instance by a wifi dongle). This can allow firmware event frames from a remote source to be processed. In the worst case scenario, by sending specially-crafted WiFi packets, a remote, unauthenticated attacker may be able to execute arbitrary code on a vulnerable system. More typically, this vulnerability will result in denial-of-service conditions.

The bug was discovered 04/17/2019. The weakness was presented 01/16/2020. This vulnerability is traded as CVE-2019-9503 since 03/01/2019. The exploitability is told to be difficult. The attack can only be initiated within the local network. The exploitation doesn't require any form of authentication. Successful exploitation requires user interaction by the victim. There are known technical details, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 274 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 282219 (Unity Linux 20.1070e Security Update: kernel (UTSA-2026-000233)), which helps to determine the existence of the flaw in a target environment. The commercial vulnerability scanner Qualys is able to test this issue with plugin 277820 (Fedora Security Update for kernel (FEDORA-2019-8219efa9f6)).

Applying the patch a4176ec356c73a46c07c181c6d04039fafa34a9f is able to eliminate this problem.

The vulnerability is also documented in the vulnerability database at Tenable (282219). See VDB-149087 for similar entry. VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• Hardware Driver Software

Vendor

• Broadcom

Name

• brcmfmac WiFi Driver

License

• commercial

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Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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