CVE-2023-21254
📋 TL;DR
This Android vulnerability allows malicious apps to retain one-time permissions after being killed, enabling local privilege escalation without user interaction. It affects Android devices running vulnerable versions, allowing attackers to gain unauthorized access to protected resources.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Malicious app gains persistent access to sensitive permissions (camera, microphone, location) without user consent, leading to complete device compromise and data exfiltration.
Likely Case
Malicious apps maintain access to permissions they shouldn't have, enabling surveillance, data theft, or further privilege escalation attacks.
If Mitigated
Proper app sandboxing and permission management limit damage to isolated app data, preventing system-wide compromise.
🎯 Exploit Status
Exploitation requires installing a malicious app but no user interaction after installation. Logic error in permission management makes exploitation straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: July 2023 Android Security Patch
Vendor Advisory: https://source.android.com/security/bulletin/2023-07-01
Restart Required: Yes
Instructions:
1. Check for Android system updates in Settings > System > System update. 2. Install July 2023 or later security patch. 3. Reboot device after installation.
🔧 Temporary Workarounds
Disable one-time permissions
androidChange permission settings to always ask or deny instead of using one-time permissions
Uninstall suspicious apps
androidRemove apps from unknown sources or with excessive permission requests
🧯 If You Can't Patch
- Restrict app installations to Google Play Store only
- Regularly review and revoke unnecessary app permissions in Settings
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About phone > Android version. If before July 2023, device is vulnerable.Check Version:
adb shell getprop ro.build.version.security_patchVerify Fix Applied:
Verify security patch level shows 'July 5, 2023' or later in Settings > About phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Unexpected permission grants after app termination
- Permission manager anomalies in system logs
Network Indicators:
- None (local privilege escalation only)
SIEM Query:
Not applicable for typical SIEM monitoring (local device issue)🔗 References
- https://android.googlesource.com/platform/frameworks/base/+/fa539c85503dc63bfb53c76b6f12b3549f14a709
- https://source.android.com/security/bulletin/2023-07-01
- https://android.googlesource.com/platform/frameworks/base/+/fa539c85503dc63bfb53c76b6f12b3549f14a709
- https://source.android.com/security/bulletin/2023-07-01
