CVE-2023-34934
📋 TL;DR
This vulnerability allows attackers to cause a Denial of Service (DoS) on H3C Magic B1ST routers by sending a specially crafted POST request that triggers a stack overflow in the Edit_BasicSSID_5G function. Attackers can crash the device, disrupting network services. Users of H3C Magic B1ST routers with firmware version V100R012 are affected.
💻 Affected Systems
- H3C Magic B1ST
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical reboot, extended network downtime, and potential for remote code execution if the overflow can be controlled to execute arbitrary code.
Likely Case
Router becomes unresponsive, requiring manual reboot to restore functionality, causing temporary network disruption.
If Mitigated
If network segmentation and access controls are implemented, impact is limited to the affected device with minimal service disruption.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. Exploitation requires sending a crafted HTTP POST request to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
Check H3C official website for firmware updates. If available, download and install the latest firmware through the router's web interface.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to the router's web management interface.
Access router web interface > Advanced Settings > Remote Management > Disable
Restrict Management Access
allLimit management interface access to trusted IP addresses only.
Access router web interface > Security > Firewall > Add rule to allow only specific IPs to port 80/443
🧯 If You Can't Patch
- Segment the router on a dedicated network segment with strict firewall rules
- Monitor network traffic for suspicious POST requests to the router's management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login > System > Firmware Version. If version is V100R012, device is vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware (or check web interface manually)Verify Fix Applied:
After applying any firmware update, verify the version no longer shows V100R012.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /cgi-bin/luci/ endpoints
- Router crash/reboot logs
- Unusual traffic patterns to router management interface
Network Indicators:
- HTTP POST requests with unusually long payloads to router IP on port 80/443
- Sudden drop in router responsiveness
SIEM Query:
source="router_logs" AND (http_method="POST" AND uri="/cgi-bin/luci/*" AND content_length>1000)