CVE-2023-35967
📋 TL;DR
Two heap-based buffer overflow vulnerabilities in Yifan YF325 routers allow remote attackers to execute arbitrary code or cause denial of service via specially crafted network requests. The vulnerabilities affect Yifan YF325 routers running version v1.0_20221108. Attackers can exploit these without authentication to potentially take full control of affected devices.
💻 Affected Systems
- Yifan YF325
📦 What is this software?
Yf325 Firmware by Yifanwireless
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement to internal networks, and persistent backdoor installation.
Likely Case
Remote code execution allowing attackers to intercept network traffic, modify device configuration, or use device as botnet node.
If Mitigated
Denial of service if exploit fails or is detected, potentially causing device reboot or service disruption.
🎯 Exploit Status
The vulnerability requires sending specially crafted network requests but does not require authentication. Technical details are publicly available in Talos reports.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No vendor advisory found
Restart Required: Yes
Instructions:
1. Contact Yifan vendor for updated firmware
2. Backup current configuration
3. Upload and install patched firmware
4. Reboot device
5. Verify firmware version
🔧 Temporary Workarounds
Network Segmentation
linuxIsolate YF325 routers from internet and restrict access to management interfaces
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
Access Control
linuxRestrict web management interface to trusted IP addresses only
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace affected devices with supported alternatives
- Implement strict network monitoring and anomaly detection for exploit attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface at http://router-ip/status or SSH/Telnet to device and run 'cat /proc/version'Check Version:
curl -s http://router-ip/status | grep -i version || ssh admin@router-ip 'cat /proc/version'Verify Fix Applied:
Verify firmware version is no longer v1.0_20221108 and test with vulnerability scanner if available📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to management CGI endpoints
- Multiple failed allocation attempts in system logs
- Process crashes related to gwcfg_cgi
Network Indicators:
- Unusual HTTP POST requests with large or malformed data to router management interface
- Traffic patterns suggesting buffer overflow attempts
SIEM Query:
source="router_logs" AND ("gwcfg_cgi" OR "malloc failed" OR "segmentation fault")