CVE-2023-21108
📋 TL;DR
This CVE describes a use-after-free vulnerability in Android's Bluetooth SDP discovery component that allows remote code execution over Bluetooth when HFP support is enabled. Attackers can exploit this without user interaction or additional privileges. All Android devices running versions 11 through 13 with Bluetooth enabled are affected.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
Android by Google
Android by Google
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing attacker to execute arbitrary code with system privileges, install malware, exfiltrate data, or join botnets.
Likely Case
Remote code execution leading to data theft, surveillance, or device takeover when Bluetooth is enabled and within range of attacker.
If Mitigated
Limited impact if Bluetooth is disabled or device is patched; attacker would need physical proximity to target device.
🎯 Exploit Status
Exploitation requires Bluetooth proximity and knowledge of the vulnerability. No authentication needed as stated in CVE description.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin June 2023 patches
Vendor Advisory: https://source.android.com/security/bulletin/2023-06-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install Android Security Patch Level dated June 2023 or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Bluetooth
androidTurn off Bluetooth completely to prevent exploitation
adb shell settings put global bluetooth_on 0
Settings > Connected devices > Connection preferences > Bluetooth > Toggle off
Disable HFP Profile
androidDisable Hands-Free Profile while keeping Bluetooth enabled for other functions
Developer options may allow disabling specific Bluetooth profiles
🧯 If You Can't Patch
- Disable Bluetooth when not in use, especially in public or untrusted environments
- Implement network segmentation to isolate vulnerable devices from critical systems
🔍 How to Verify
Check if Vulnerable:
Check Android Security Patch Level in Settings > About phone > Android version. If patch level is before June 2023, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Security Patch Level shows June 2023 or later after applying updates.📡 Detection & Monitoring
Log Indicators:
- Unusual Bluetooth connection attempts
- SDP discovery errors in Bluetooth logs
- Process crashes in Bluetooth services
Network Indicators:
- Suspicious Bluetooth traffic patterns
- Unexpected Bluetooth pairing requests
SIEM Query:
source="android_logs" AND (process="bluetooth" OR process="com.android.bluetooth") AND (message="*sdpu_build_uuid_seq*" OR message="*use-after-free*")