CVE-2023-20965
📋 TL;DR
This vulnerability in Android's Wi-Fi Trust On First Use (TOFU) flow allows credential disclosure due to a logic error in ClientModeImpl.java. Attackers can remotely escalate privileges without user interaction or additional execution privileges. Affects Android devices with vulnerable Wi-Fi modules.
💻 Affected Systems
- Android
📦 What is this software?
Android by Google
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attackers to steal Wi-Fi credentials, intercept network traffic, and potentially gain persistent access to the device.
Likely Case
Credential theft leading to unauthorized network access, man-in-the-middle attacks, and potential lateral movement within networks.
If Mitigated
Limited impact if devices are patched, network segmentation is implemented, and Wi-Fi security policies are enforced.
🎯 Exploit Status
No user interaction required, making exploitation straightforward once the vulnerability is understood. References suggest the issue is in the TOFU flow logic.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: August 2023 Android Security Patch or later
Vendor Advisory: https://source.android.com/security/bulletin/2023-08-01
Restart Required: Yes
Instructions:
1. Apply the August 2023 Android Security Patch via Settings > System > System Update. 2. Ensure the device reboots after installation. 3. Verify the patch level in Settings > About Phone > Android version.
🔧 Temporary Workarounds
Disable Wi-Fi Auto-Connect
androidPrevent automatic connection to unknown Wi-Fi networks to reduce exposure to TOFU attacks.
Settings > Network & Internet > Wi-Fi > Wi-Fi preferences > Turn off 'Connect to open networks' and 'Turn on Wi-Fi automatically'
Use Only Trusted Networks
androidConfigure devices to connect only to pre-approved, secure Wi-Fi networks.
Settings > Network & Internet > Wi-Fi > Forget untrusted networks and only save known secure networks
🧯 If You Can't Patch
- Segment network traffic to isolate vulnerable devices and limit lateral movement.
- Implement network monitoring for unusual Wi-Fi authentication attempts and credential exfiltration patterns.
🔍 How to Verify
Check if Vulnerable:
Check Android security patch level in Settings > About Phone > Android version. If patch level is before August 2023, the device is vulnerable.Check Version:
Settings > About Phone > Android version > Security patch levelVerify Fix Applied:
Verify the security patch level shows 'August 5, 2023' or later in Settings > About Phone > Android version.📡 Detection & Monitoring
Log Indicators:
- Unusual Wi-Fi authentication failures, unexpected credential storage access, or TOFU flow anomalies in system logs
Network Indicators:
- Suspicious Wi-Fi probe requests, unexpected authentication attempts from unknown MAC addresses, or credential transmission to unexpected endpoints
SIEM Query:
source="android_system_logs" AND (event="wifi_auth_failure" OR event="credential_access") AND severity=HIGH🔗 References
- https://android.googlesource.com/platform/packages/modules/Wifi/+/0d3cb609b0851ea9e5745cc6101e57c2e5e739f2
- https://android.googlesource.com/platform/packages/modules/Wifi/+/88a8a98934215f591605028e200b6eca8f7cc45a
- https://android.googlesource.com/platform/packages/modules/Wifi/+/bd318b9772759546509f6fdb8648366099dd65ad
- https://source.android.com/security/bulletin/2023-08-01
- https://android.googlesource.com/platform/packages/modules/Wifi/+/0d3cb609b0851ea9e5745cc6101e57c2e5e739f2
- https://android.googlesource.com/platform/packages/modules/Wifi/+/88a8a98934215f591605028e200b6eca8f7cc45a
- https://android.googlesource.com/platform/packages/modules/Wifi/+/bd318b9772759546509f6fdb8648366099dd65ad
- https://source.android.com/security/bulletin/2023-08-01
