CVE-2024-38408: Qualcomm Wsa8845h Cryptographic Vulnerability

CVE-2024-38408 Overview

CVE-2024-38408 is a cryptographic vulnerability affecting Qualcomm Bluetooth controllers that occurs when a controller receives an LMP (Link Manager Protocol) start encryption command under unexpected conditions. This flaw in the Bluetooth encryption handling mechanism can allow attackers to compromise the confidentiality and integrity of Bluetooth communications on a massive scale of affected devices.

Critical Impact

This vulnerability enables network-based attackers to exploit improper cryptographic handling in Qualcomm Bluetooth controllers, potentially allowing unauthorized access to encrypted communications across hundreds of affected Qualcomm chipsets spanning mobile devices, automotive systems, IoT platforms, and compute devices.

Affected Products

• Qualcomm Snapdragon 8 Gen 3/2/1 Mobile Platforms
• Qualcomm Snapdragon 888/865/855 5G Mobile Platforms
• Qualcomm FastConnect 7800/6900/6800/6700/6200 Wi-Fi/Bluetooth Modules
• Qualcomm Automotive Platforms (SA8775P, SA8295P, SA8255P, SA8195P, SA8155P)
• Qualcomm Snapdragon X75/X72/X65/X55 5G Modem-RF Systems
• Qualcomm WCN7881/7880/7861/7860/6755/6740/3988/3980 Wireless Connectivity Chips
• Qualcomm Immersive Home 318/316/216/214 Platforms
• Qualcomm Robotics RB5 Platform
• Qualcomm QCN9274/9100/9074/9000 Series Network Processors

Discovery Timeline

• November 4, 2024 - CVE-2024-38408 published to NVD
• November 8, 2024 - Last updated in NVD database

Technical Details for CVE-2024-38408

Vulnerability Analysis

This vulnerability exists in the Bluetooth controller firmware's handling of LMP encryption commands. The Link Manager Protocol is responsible for establishing and managing Bluetooth connections, including the negotiation and initiation of encryption. When the controller receives an LMP_start_encryption_req command in an unexpected state or under improper conditions, the cryptographic state machine fails to properly validate the context, leading to a security bypass.

The flaw allows attackers within Bluetooth range (or potentially over network if bridged) to manipulate the encryption establishment process. Since the vulnerability can be exploited without user interaction and requires no privileges, it poses significant risk to the vast ecosystem of devices using affected Qualcomm chipsets. The impact includes potential compromise of both confidentiality and integrity of Bluetooth communications, though availability is not affected according to the vulnerability assessment.

The extensive list of affected products spans consumer mobile devices (smartphones, tablets), automotive infotainment and telematics systems, IoT devices, wearables, laptops with Qualcomm compute platforms, and network infrastructure equipment—representing billions of potentially vulnerable devices worldwide.

Root Cause

The root cause is a cryptographic implementation flaw (CWE-310) in the Bluetooth controller's LMP encryption handling logic. The controller does not properly validate the state machine conditions before processing encryption start commands, allowing the command to be processed in contexts where encryption parameters may not be properly established or where the encryption context can be manipulated by an attacker.

This type of vulnerability typically arises from incomplete state validation in protocol implementations, where the firmware accepts cryptographically sensitive operations without verifying that all prerequisite security conditions have been met.

Attack Vector

An attacker can exploit this vulnerability through the following attack flow:

1. The attacker establishes or intercepts a Bluetooth connection to a target device with a vulnerable Qualcomm chipset
2. During the link establishment or at a point where encryption is being negotiated, the attacker sends or manipulates LMP packets
3. By triggering the LMP_start_encryption_req command under unexpected conditions, the attacker can bypass proper encryption establishment
4. This may allow the attacker to force weak encryption, bypass encryption entirely, or establish encryption with compromised keys
5. Once the cryptographic protections are bypassed, the attacker can intercept or modify Bluetooth traffic

The attack can be conducted over the network without requiring authentication or user interaction, making it particularly dangerous in scenarios where devices are paired or pairing with untrusted Bluetooth peripherals.

Detection Methods for CVE-2024-38408

Indicators of Compromise

• Unusual Bluetooth LMP protocol activity or unexpected encryption renegotiation events in Bluetooth stack logs
• Bluetooth connections experiencing unexpected encryption state changes or downgrades
• Anomalous Bluetooth traffic patterns suggesting man-in-the-middle positioning
• Device firmware version checks revealing vulnerable Qualcomm chipset firmware versions

Detection Strategies

• Deploy endpoint detection solutions capable of monitoring Bluetooth stack behavior and identifying protocol anomalies
• Implement network monitoring for devices with Bluetooth-to-network bridges to detect unusual traffic patterns
• Utilize firmware version inventory management to identify devices running vulnerable Qualcomm firmware
• Monitor for security advisories from device manufacturers regarding firmware updates for this CVE

Monitoring Recommendations

• Enable verbose Bluetooth logging on critical devices where supported to capture LMP-level events
• Deploy SentinelOne agents on supported platforms to detect exploitation attempts through behavioral analysis
• Conduct regular firmware audits of devices containing Qualcomm Bluetooth chipsets
• Establish alerting for Bluetooth-related security events in enterprise MDM solutions

How to Mitigate CVE-2024-38408

Immediate Actions Required

• Review the Qualcomm Security Bulletin November 2024 to identify affected products in your environment
• Contact device manufacturers for firmware update availability timelines for affected devices
• Prioritize patching for devices handling sensitive communications or in high-risk environments
• Consider temporarily disabling Bluetooth on critical devices where feasible until patches are applied
• Implement network segmentation to isolate Bluetooth-enabled devices from sensitive network resources

Patch Information

Qualcomm has disclosed this vulnerability in their November 2024 Security Bulletin. Firmware patches are distributed through device manufacturers (OEMs) who integrate Qualcomm chipsets into their products. Organizations should:

1. Check with device manufacturers (e.g., Samsung, Google, OnePlus, automotive OEMs) for security updates addressing CVE-2024-38408
2. Apply firmware updates through the device's standard update mechanism
3. For automotive and IoT devices, coordinate with equipment vendors for firmware update procedures
4. Verify patch application by checking firmware versions against manufacturer advisories

Workarounds

• Disable Bluetooth functionality on devices that do not require it for business operations
• Avoid pairing Bluetooth devices in public or untrusted environments until patched
• Use wired alternatives to Bluetooth peripherals where possible for sensitive communications
• Implement Bluetooth device allowlisting in enterprise environments to limit pairing to known devices

# Example: Disable Bluetooth on Linux systems with affected Qualcomm chipsets
# Check if Bluetooth is enabled
systemctl status bluetooth

# Disable Bluetooth service
sudo systemctl stop bluetooth
sudo systemctl disable bluetooth

# For Android devices (requires root or ADB):
# adb shell settings put global bluetooth_on 0