CVE-2021-0642
📋 TL;DR
This Android vulnerability allows local apps to retrieve a trackable identifier from the voicemail settings component without proper permissions. It affects Android devices running versions 8.1 through 11. User interaction is required for exploitation, making it an information disclosure issue.
💻 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
Malicious app could persistently track user's device identifier, enabling profiling or correlation with other data leaks.
Likely Case
Limited information disclosure to apps already installed on device, potentially enabling targeted advertising or tracking.
If Mitigated
No impact if proper Android security updates are applied or if users avoid installing untrusted apps.
🎯 Exploit Status
Requires user to install malicious app and interact with voicemail settings. No public exploit code known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Android Security Bulletin August 2021 patches
Vendor Advisory: https://source.android.com/security/bulletin/2021-08-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > Advanced > System update. 2. Install August 2021 security patch or later. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable Voicemail Settings Access
androidPrevent apps from accessing voicemail settings component
adb shell pm disable-user --user 0 com.android.phone
Restrict App Permissions
androidReview and restrict permissions for all installed apps
🧯 If You Can't Patch
- Avoid installing untrusted apps from unknown sources
- Regularly review app permissions and remove unnecessary ones
🔍 How to Verify
Check if Vulnerable:
Check Android version in Settings > About phone > Android version. If version is 8.1, 9, 10, or 11 without August 2021 security patch, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify Android Security Patch Level in Settings > About phone shows August 2021 or later.📡 Detection & Monitoring
Log Indicators:
- Unusual access to VoicemailSettingsFragment component
- Permission denial logs for com.android.phone
Network Indicators:
- None - local vulnerability only
SIEM Query:
Not applicable for typical SIEM monitoring as this is local Android component access.