CVE-2023-33643
📋 TL;DR
This CVE describes a stack overflow vulnerability in H3C Magic R300 routers that allows remote attackers to execute arbitrary code via the AddWlanMacList interface. Attackers can exploit this by sending specially crafted requests to the vulnerable endpoint, potentially gaining full control of affected devices. Only H3C Magic R300 routers running specific firmware versions are affected.
💻 Affected Systems
- H3C Magic R300
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to install persistent malware, intercept all network traffic, pivot to internal networks, and use device as botnet node.
Likely Case
Remote code execution leading to device takeover, network traffic interception, and potential credential theft from connected devices.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Public exploit details available; exploitation requires network access to device web interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: Yes
Instructions:
1. Check H3C official website for firmware updates
2. Download latest firmware for R300 model
3. Access router admin interface
4. Navigate to firmware update section
5. Upload and apply new firmware
6. Reboot router after update
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Access router admin panel -> Advanced Settings -> Remote Management -> Disable
Restrict Access via Firewall
linuxBlock access to port 80/443 from untrusted networks
iptables -A INPUT -p tcp --dport 80 -s ! 192.168.1.0/24 -j DROP
iptables -A INPUT -p tcp --dport 443 -s ! 192.168.1.0/24 -j DROP
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict access controls
- Implement network monitoring for unusual traffic patterns to/from router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or About sectionCheck Version:
curl -s http://router-ip/goform/getStatus | grep versionVerify Fix Applied:
Verify firmware version has changed from vulnerable version and test AddWlanMacList endpoint with safe payload📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /goform/aspForm with AddWlanMacList parameter
- Unusual buffer overflow errors in system logs
- Failed authentication attempts followed by exploitation attempts
Network Indicators:
- Unusual outbound connections from router
- Traffic spikes to/from router management interface
- POST requests with large payloads to /goform/aspForm
SIEM Query:
source="router.log" AND (uri="/goform/aspForm" OR message="*AddWlanMacList*" OR message="*buffer overflow*")