CVE-2025-4356
📋 TL;DR
A critical stack-based buffer overflow vulnerability in Tenda DAP-1520 routers allows remote attackers to execute arbitrary code by sending specially crafted requests to the authentication handler. This affects users running vulnerable firmware versions, potentially giving attackers full control of affected devices.
💻 Affected Systems
- Tenda DAP-1520
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, credential theft, network pivoting, and persistent backdoor installation.
Likely Case
Device takeover enabling man-in-the-middle attacks, DNS hijacking, and network surveillance.
If Mitigated
Limited impact if devices are behind firewalls with strict inbound filtering and network segmentation.
🎯 Exploit Status
Public exploit code exists in GitHub repository. Remote exploitation without authentication makes this highly attractive to attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.tenda.com.cn/
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. Download latest firmware. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and apply new firmware. 6. Reboot device.
🔧 Temporary Workarounds
Network Isolation
allPlace affected devices in isolated VLAN with strict firewall rules
Access Restriction
linuxBlock external access to router management interface
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Replace vulnerable devices with supported models
- Implement strict network segmentation and monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under System Status or Firmware Upgrade sectionCheck Version:
curl -s http://router-ip/status.cgi | grep firmware_versionVerify Fix Applied:
Verify firmware version is newer than 1.10B04_BETA02 and no longer shows vulnerable version📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts
- Multiple requests to /storage endpoint
- Crash logs from authentication handler
Network Indicators:
- Unusual traffic patterns to router management interface
- Exploit-specific payload patterns in HTTP requests
SIEM Query:
source="router.logs" AND (uri="/storage" OR process="mod_graph_auth_uri_handler") AND status=500