CVE-2021-35123
📋 TL;DR
This is a buffer overflow vulnerability in Qualcomm's Snapdragon chipsets affecting GATT multi-notification functionality. Attackers can exploit this by sending specially crafted Bluetooth packets to execute arbitrary code or cause denial of service. Affected devices include those using vulnerable Snapdragon Connectivity and Snapdragon Industrial IoT chips.
💻 Affected Systems
- Snapdragon Connectivity
- Snapdragon Industrial IOT
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution with kernel privileges leading to complete device compromise, data theft, or persistent backdoor installation.
Likely Case
Denial of service causing device crashes or instability, potentially requiring physical reset.
If Mitigated
Limited impact if Bluetooth is disabled or devices are air-gapped from untrusted networks.
🎯 Exploit Status
Exploitation requires Bluetooth proximity and knowledge of vulnerable devices. No public exploit code available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Refer to Qualcomm April 2022 security bulletin for specific chipset firmware updates
Vendor Advisory: https://www.qualcomm.com/company/product-security/bulletins/april-2022-bulletin
Restart Required: Yes
Instructions:
1. Check device manufacturer for firmware updates. 2. Apply Qualcomm-provided patches through OEM updates. 3. Reboot device after update.
🔧 Temporary Workarounds
Disable Bluetooth
allTurn off Bluetooth when not in use to prevent exploitation
adb shell settings put global bluetooth_on 0
systemctl stop bluetooth
Restrict Bluetooth visibility
linuxSet devices to non-discoverable mode and use whitelisting
hciconfig hci0 noscan
bluetoothctl discoverable off
🧯 If You Can't Patch
- Segment Bluetooth networks and restrict device proximity to untrusted sources
- Implement physical security controls to prevent unauthorized Bluetooth access
🔍 How to Verify
Check if Vulnerable:
Check device chipset model and firmware version against Qualcomm's advisory. Use 'getprop ro.bootloader' or similar on Android devices.Check Version:
adb shell getprop ro.bootloader || cat /proc/device-tree/modelVerify Fix Applied:
Verify firmware version has been updated to post-April 2022 release and test Bluetooth functionality.📡 Detection & Monitoring
Log Indicators:
- Bluetooth stack crashes
- Kernel panic logs
- Unexpected GATT notification errors
Network Indicators:
- Unusual Bluetooth connection attempts
- Malformed Bluetooth packets detected
SIEM Query:
source="bluetoothd" AND (event="crash" OR event="buffer_overflow")