CVE-2023-20991
📋 TL;DR
This CVE describes an out-of-bounds read vulnerability in Android's Bluetooth Low Energy (BLE) scanner component. It allows local information disclosure when exploited by an attacker with system execution privileges, affecting Android 13 devices. No user interaction is required for exploitation.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
An attacker with system privileges could read sensitive memory contents from adjacent processes, potentially exposing cryptographic keys, authentication tokens, or other protected data.
Likely Case
Limited information disclosure of non-critical memory contents due to the need for system privileges and the specific nature of the BLE component.
If Mitigated
Minimal impact if proper privilege separation and memory protection mechanisms are in place.
🎯 Exploit Status
Exploitation requires system privileges and knowledge of the specific memory layout. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Patch Level June 2023 or later
Vendor Advisory: https://source.android.com/security/bulletin/pixel/2023-06-01
Restart Required: Yes
Instructions:
1. Check for system updates in Settings > System > System update. 2. Install the June 2023 or later Android security patch. 3. Reboot the device after installation.
🔧 Temporary Workarounds
Disable Bluetooth when not in use
androidReduces attack surface by disabling the vulnerable BLE component
adb shell settings put global bluetooth_on 0
🧯 If You Can't Patch
- Restrict installation of untrusted applications that could gain system privileges
- Implement strict privilege separation and monitor for unusual system process behavior
🔍 How to Verify
Check if Vulnerable:
Check Android version and security patch level in Settings > About phone > Android versionCheck Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level is June 2023 or later in Settings > About phone > Android version📡 Detection & Monitoring
Log Indicators:
- Unusual Bluetooth stack crashes or memory access violations in system logs
Network Indicators:
- None - this is a local vulnerability
SIEM Query:
source="android_system" AND (event="btm_ble_process_periodic_adv_sync_lost_evt" OR error="memory_access_violation")