CVE-2021-37577
📋 TL;DR
This Bluetooth vulnerability allows an unauthenticated attacker to perform a man-in-the-middle attack during pairing to discover the passkey. It affects devices using Bluetooth Core Specifications 2.1 through 5.3 with Secure Connections or Secure Simple Pairing using Passkey entry protocol. The attacker can then impersonate the legitimate device and complete authenticated pairing.
💻 Affected Systems
- Any device with Bluetooth functionality
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains unauthorized access to Bluetooth devices, potentially intercepting sensitive data, injecting malicious commands, or taking control of connected devices.
Likely Case
Attacker eavesdrops on Bluetooth communications, potentially capturing authentication credentials, personal data, or establishing unauthorized connections.
If Mitigated
Limited impact with proper network segmentation, Bluetooth usage policies, and monitoring for unusual pairing attempts.
🎯 Exploit Status
Requires physical proximity and specific timing during pairing process. Related to CVE-2020-26558 with similar attack vectors.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Bluetooth Core Specification 5.4 and later
Vendor Advisory: https://www.bluetooth.com/learn-about-bluetooth/key-attributes/bluetooth-security/reporting-security/
Restart Required: Yes
Instructions:
1. Check with device manufacturer for firmware/software updates. 2. Apply Bluetooth stack updates from OS vendor. 3. Update to Bluetooth 5.4+ compliant hardware if possible. 4. Restart devices after updates.
🔧 Temporary Workarounds
Disable Bluetooth when not in use
linuxTurn off Bluetooth functionality to prevent pairing attacks
sudo rfkill block bluetooth
bluetoothctl power off
Use alternative pairing methods
allUse NFC, QR codes, or Just Works pairing instead of Passkey entry
🧯 If You Can't Patch
- Restrict Bluetooth usage to trusted environments only
- Implement network segmentation for Bluetooth-connected devices
🔍 How to Verify
Check if Vulnerable:
Check Bluetooth specification version in device settings or using 'bluetoothctl show' on Linux. If using Bluetooth 2.1-5.3 with Passkey entry pairing, device is vulnerable.Check Version:
bluetoothctl --version (Linux) or check device Bluetooth specifications in system settingsVerify Fix Applied:
Verify Bluetooth specification version is 5.4+ or check for manufacturer security patches addressing CVE-2021-37577.📡 Detection & Monitoring
Log Indicators:
- Multiple failed pairing attempts
- Unusual Bluetooth pairing from unknown devices
- Pairing events outside normal hours
Network Indicators:
- Bluetooth traffic patterns showing man-in-the-middle characteristics
- Unexpected device connections
SIEM Query:
source="bluetooth" AND (event="pairing_failed" OR event="unauthorized_pairing")