CVE-2023-34924
📋 TL;DR
H3C Magic B1STW B1STV100R012 routers contain a stack overflow vulnerability in the SetAPInfoById function that allows attackers to cause Denial of Service (DoS) via crafted POST requests. This affects users of these specific H3C router models running vulnerable firmware. Attackers can crash the device, disrupting network connectivity.
💻 Affected Systems
- H3C Magic B1STW B1STV100R012
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical reboot, extended network downtime, potential for remote code execution if stack overflow can be leveraged for arbitrary code execution.
Likely Case
Router becomes unresponsive, requiring manual reboot to restore functionality, causing temporary network disruption.
If Mitigated
No impact if device is patched or network segmentation prevents access to vulnerable interface.
🎯 Exploit Status
Public proof-of-concept available on GitHub demonstrates exploitation via crafted POST request to vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check H3C official website for firmware updates. If update available, download and apply through router web interface or CLI.
🔧 Temporary Workarounds
Network Segmentation
allIsolate router management interface from untrusted networks
Access Control Lists
linuxRestrict access to router management interface to trusted IPs only
# Example: iptables -A INPUT -p tcp --dport 80 -s trusted_ip -j ACCEPT
# iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Disable remote management interface if not required
- Implement network monitoring for abnormal POST requests to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface (typically under System > Firmware) or CLI using 'show version' commandCheck Version:
show version (CLI) or check web interface System Information pageVerify Fix Applied:
Verify firmware version has been updated to a version later than B1STV100R012📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to router management interface with abnormal payload sizes
- Router crash/reboot logs
- Connection refused errors after exploitation
Network Indicators:
- Abnormal POST requests to router IP on management ports (typically 80, 443, 8080)
- Sudden drop in router responsiveness
SIEM Query:
source="router_logs" AND (http_method="POST" AND (uri_path="/cgi-bin/luci" OR user_agent CONTAINS "exploit") AND bytes > 1000)