CVE-2020-0556
📋 TL;DR
CVE-2020-0556 is an improper access control vulnerability in BlueZ (Linux Bluetooth stack) that allows unauthenticated attackers within Bluetooth range to potentially escalate privileges or cause denial of service. This affects Linux systems using BlueZ before version 5.54 with Bluetooth enabled. The vulnerability requires physical proximity to the target device.
💻 Affected Systems
- BlueZ (Linux Bluetooth stack)
📦 What is this software?
Bluez by Bluez
Leap by Opensuse
Leap by Opensuse
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
Ubuntu Linux by Canonical
⚠️ Risk & Real-World Impact
Worst Case
Local privilege escalation to root, complete system compromise, and persistent access via Bluetooth interface
Likely Case
Denial of service on Bluetooth services, potential unauthorized access to Bluetooth-connected devices
If Mitigated
Limited impact with Bluetooth disabled or proper network segmentation
🎯 Exploit Status
Exploitation requires Bluetooth proximity and specific conditions; no public exploit code available
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: BlueZ 5.54 or later
Vendor Advisory: https://usn.ubuntu.com/4311-1/
Restart Required: Yes
Instructions:
1. Update BlueZ package using your distribution's package manager
2. For Ubuntu/Debian: sudo apt update && sudo apt upgrade bluez
3. For openSUSE: sudo zypper update bluez
4. Restart Bluetooth service: sudo systemctl restart bluetooth
5. Reboot system to ensure complete patch application
🔧 Temporary Workarounds
Disable Bluetooth Service
linuxTemporarily disable Bluetooth to prevent exploitation
sudo systemctl stop bluetooth
sudo systemctl disable bluetooth
Disable Bluetooth Hardware
linuxTurn off Bluetooth at hardware level
sudo rfkill block bluetooth
🧯 If You Can't Patch
- Disable Bluetooth on all affected systems immediately
- Implement network segmentation to isolate Bluetooth-enabled devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check BlueZ version: bluetoothctl --version | grep -i bluezCheck Version:
bluetoothctl --versionVerify Fix Applied:
Verify BlueZ version is 5.54 or higher: dpkg -l | grep bluez (Debian/Ubuntu) or rpm -qa | grep bluez (RHEL/SUSE)📡 Detection & Monitoring
Log Indicators:
- Unusual Bluetooth connection attempts in /var/log/syslog
- BlueZ service crashes or restarts
Network Indicators:
- Unexpected Bluetooth pairing requests
- Abnormal Bluetooth traffic patterns
SIEM Query:
source="syslog" AND ("bluetooth" OR "bluez") AND ("error" OR "failed" OR "unauthorized")🔗 References
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00008.html
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00055.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00008.html
- https://security.gentoo.org/glsa/202003-49
- https://usn.ubuntu.com/4311-1/
- https://www.debian.org/security/2020/dsa-4647
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00352.html
- http://lists.opensuse.org/opensuse-security-announce/2020-04/msg00008.html
- http://lists.opensuse.org/opensuse-security-announce/2020-06/msg00055.html
- https://lists.debian.org/debian-lts-announce/2020/06/msg00008.html
- https://security.gentoo.org/glsa/202003-49
- https://usn.ubuntu.com/4311-1/
- https://www.debian.org/security/2020/dsa-4647
- https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00352.html
