CVE-2021-33590
📋 TL;DR
CVE-2021-33590 is a stack-based buffer over-read vulnerability in GattLib's get_device_path_from_mac function that allows reading beyond allocated memory boundaries. This affects systems using GattLib 0.3-rc1 for Bluetooth communication, potentially exposing sensitive data or causing crashes.
💻 Affected Systems
- GattLib
📦 What is this software?
Gattlib by Labapart
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data exfiltration, or persistent backdoor installation.
Likely Case
Application crash (denial of service) or information disclosure of adjacent memory contents.
If Mitigated
Limited impact with proper memory protection mechanisms (ASLR, stack canaries) and network segmentation.
🎯 Exploit Status
Proof of concept available in GitHub issue #219. Exploitation requires sending specially crafted Bluetooth messages to trigger the buffer over-read.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.3 or later
Vendor Advisory: https://github.com/labapart/gattlib/issues/219
Restart Required: Yes
Instructions:
1. Update GattLib to version 0.3 or later. 2. Recompile any applications using GattLib. 3. Restart affected services or systems.
🔧 Temporary Workarounds
Disable Bluetooth services
linuxTemporarily disable Bluetooth functionality if not required
sudo systemctl stop bluetooth
sudo systemctl disable bluetooth
Network segmentation
allIsolate Bluetooth devices and services from critical networks
🧯 If You Can't Patch
- Implement strict network segmentation for Bluetooth-enabled devices
- Deploy memory protection mechanisms (ASLR, stack canaries) and monitor for crashes
🔍 How to Verify
Check if Vulnerable:
Check GattLib version: dpkg -l | grep gattlib or check package manager. If version is 0.3-rc1, system is vulnerable.Check Version:
dpkg -l | grep gattlib || rpm -qa | grep gattlib || find /usr -name '*gattlib*' -type fVerify Fix Applied:
Verify GattLib version is 0.3 or later and test Bluetooth functionality.📡 Detection & Monitoring
Log Indicators:
- Application crashes related to gattlib or Bluetooth services
- Memory access violation errors in system logs
Network Indicators:
- Unusual Bluetooth traffic patterns
- Multiple connection attempts to Bluetooth services
SIEM Query:
source="*syslog*" AND ("gattlib" OR "bluetooth") AND ("segmentation fault" OR "memory violation" OR "crash")