CVE-2020-3645 in Snapdragon Compute
Summary
by MITRE
Firmware will hit assert in WLAN firmware If encrypted data length in FILS IE of reassoc response is more than 528 bytes in Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer Electronics Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wired Infrastructure and Networking in IPQ6018, IPQ8074, Kamorta, Nicobar, QCA6390, QCA8081, QCN7605, QCS404, QCS405, QCS605, Rennell, SC7180, SC8180X, SDA845, SDM670, SDM710, SDM845, SDM850, SM6150, SM7150, SM8150, SXR1130, SXR2130
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Analysis
by VulDB Data Team • 10/21/2020
This vulnerability resides in the WLAN firmware of various Qualcomm Snapdragon chipsets and represents a critical assertion failure that can lead to system instability and potential denial of service conditions. The flaw specifically manifests when processing encrypted data within the Fast Initial Link Setup Information Element of a reassociation response frame, where the encrypted data length exceeds 528 bytes. This condition triggers an assertion within the firmware code, causing the system to halt execution and potentially crash the wireless connectivity functionality. The vulnerability affects a broad range of Snapdragon product lines including compute, connectivity, consumer electronics, consumer IoT, industrial IoT, mobile, voice and music, and wired infrastructure and networking platforms, demonstrating the widespread nature of this firmware issue across Qualcomm's ecosystem.
The technical implementation of this vulnerability involves the processing of IEEE 802.11 Fast Initial Link Setup (FILS) protocol elements within the reassociation response mechanism. When a wireless client attempts to reassociate with an access point using FILS authentication, the response may contain an Information Element with encrypted data. The firmware validation logic fails to properly handle cases where the encrypted data exceeds the expected 528-byte limit, causing an assertion failure that terminates the firmware execution thread. This behavior aligns with CWE-611 Improper Restriction of XML External Entity Reference, as the firmware fails to properly validate input data boundaries, and can be categorized under ATT&CK technique T1499.004 Network Denial of Service through firmware-level assertion failures that disrupt network connectivity. The affected chipsets span multiple generations and product families, indicating a fundamental flaw in the firmware validation logic rather than a specific hardware implementation issue.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the overall network connectivity and device functionality. When the assertion failure occurs, it can cause the wireless subsystem to become unresponsive, forcing users to manually restart their devices or reconfigure network settings. In enterprise environments where wireless connectivity is critical for operations, this vulnerability could result in significant downtime and productivity losses. The vulnerability is particularly concerning for devices that rely heavily on wireless connectivity for their primary functions, such as IoT devices, mobile phones, and networking equipment. The condition can be triggered remotely through malicious wireless access points that craft specially formatted reassociation responses, making this a potential vector for targeted attacks against vulnerable devices.
Mitigation strategies for this vulnerability should focus on firmware updates from device manufacturers, as the issue stems from the firmware implementation rather than the hardware itself. System administrators and device manufacturers should prioritize rolling out firmware patches that properly validate the encrypted data length in FILS IE elements and implement appropriate error handling instead of assertion failures. Additional defensive measures include network monitoring to detect unusual reassociation patterns that might indicate exploitation attempts, and implementing wireless network segmentation to limit the impact of potential attacks. Organizations should also consider disabling FILS authentication mechanisms on affected devices until proper patches are deployed, though this may reduce security benefits. The vulnerability highlights the importance of robust input validation in embedded systems and firmware code, emphasizing the need for proper boundary checking and error handling as outlined in security best practices for embedded device development and the NIST Cybersecurity Framework.