CVE-2024-11494
📋 TL;DR
This vulnerability allows unauthenticated attackers to read device information from Zyxel P-6101C ADSL modems via crafted HTTP HEAD requests. It affects users of the specific firmware version who have not applied mitigations. The vulnerability exists due to improper authentication mechanisms.
💻 Affected Systems
- Zyxel P-6101C ADSL modem
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could gather detailed device information that could be used for further attacks, network reconnaissance, or identifying vulnerable devices for exploitation.
Likely Case
Information disclosure revealing device details, firmware version, and potentially other system information that could aid attackers in planning additional attacks.
If Mitigated
Limited impact with proper network segmentation and access controls preventing external access to the modem's management interface.
🎯 Exploit Status
The GitHub reference shows technical details and likely contains exploit code. HTTP HEAD method exploitation is straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: None available
Restart Required: No
Instructions:
No official patch exists as this is an unsupported legacy device. Consider replacement or workarounds.
🔧 Temporary Workarounds
Disable WAN management access
allPrevent external access to the modem's management interface by disabling WAN/remote management features
Access modem web interface > Management > Access Control > Disable 'Remote Management'
Implement network segmentation
allIsolate the modem on a separate network segment with strict firewall rules
🧯 If You Can't Patch
- Replace the legacy modem with a supported model
- Implement strict network access controls to limit who can reach the modem's management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in modem web interface under System > Status > Firmware VersionCheck Version:
curl -I http://[modem-ip]/ or check web interfaceVerify Fix Applied:
Test with HTTP HEAD requests to the modem's management interface to confirm information disclosure is prevented📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP HEAD requests to modem management interface
- Multiple failed authentication attempts followed by HEAD requests
Network Indicators:
- HTTP HEAD requests to modem management ports (typically 80/443)
- Unusual traffic patterns to legacy modem devices
SIEM Query:
source="modem-logs" AND (method="HEAD" OR uri CONTAINS "/cgi-bin/")