CVE-2020-25854
📋 TL;DR
This vulnerability in Realtek RTL8195A Wi-Fi modules allows remote code execution or denial of service through a stack buffer overflow during WPA2 handshake processing. An attacker who knows the network's PSK can impersonate an access point and send crafted packets to exploit vulnerable Wi-Fi clients. Devices using affected Realtek firmware versions are at risk.
💻 Affected Systems
- Realtek RTL8195A Wi-Fi Module
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full remote code execution on vulnerable Wi-Fi clients, allowing complete device compromise and potential lateral movement within networks.
Likely Case
Denial of service attacks crashing Wi-Fi functionality, disrupting connectivity for affected devices.
If Mitigated
Limited impact if devices are patched or isolated from untrusted networks, though risk remains in public Wi-Fi scenarios.
🎯 Exploit Status
Exploitation requires knowledge of the network's PSK and ability to impersonate an access point during WPA2 handshake.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 2.08 and later (released April 2020)
Vendor Advisory: https://www.vdoo.com/blog/realtek-rtl8195a-vulnerabilities-discovered/
Restart Required: Yes
Instructions:
1. Contact device manufacturer for updated firmware. 2. Download firmware version 2.08 or later. 3. Follow manufacturer's flashing instructions. 4. Reboot device after update.
🔧 Temporary Workarounds
Network Isolation
allIsolate vulnerable devices from untrusted networks and limit Wi-Fi exposure.
WPA3 Migration
allMigrate to WPA3 networks where supported to avoid WPA2 handshake vulnerabilities.
🧯 If You Can't Patch
- Segment network to isolate vulnerable devices from critical systems
- Implement strict network access controls and monitor for suspicious Wi-Fi handshake activity
🔍 How to Verify
Check if Vulnerable:
Check device firmware version via manufacturer interface or command: systeminfo | findstr /i firmwareCheck Version:
systeminfo | findstr /i firmware (Windows) or dmesg | grep -i firmware (Linux)Verify Fix Applied:
Verify firmware version is 2.08 or higher after update📡 Detection & Monitoring
Log Indicators:
- Multiple failed WPA2 handshakes
- Wi-Fi module crash logs
- Unexpected firmware resets
Network Indicators:
- Unusual WPA2 handshake patterns
- Spoofed access point beacons
- Malformed 802.11 packets
SIEM Query:
source="wifi_logs" AND (event="handshake_failure" OR event="buffer_overflow")