CVE-2024-57681
📋 TL;DR
An access control vulnerability in D-Link DIR-816 routers allows unauthenticated attackers to modify the agl service configuration via crafted POST requests to form2alg.cgi. This affects D-Link DIR-816A2 routers running vulnerable firmware versions. Attackers can potentially manipulate device services without authentication.
💻 Affected Systems
- D-Link DIR-816A2
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers could reconfigure router services to intercept traffic, redirect DNS, or create backdoors for persistent access to the network.
Likely Case
Attackers modify service configurations to degrade network performance or enable further exploitation of the device.
If Mitigated
With proper network segmentation and access controls, impact is limited to the router itself without lateral movement.
🎯 Exploit Status
Exploitation requires sending a crafted POST request to the vulnerable endpoint
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.dlink.com/en/security-bulletin/
Restart Required: No
Instructions:
Check D-Link security bulletin for firmware updates. If available, download from official D-Link support site and upload via router web interface.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router web interface
Access router admin panel > Advanced > Remote Management > Disable
Network Segmentation
allIsolate router management interface from user networks
🧯 If You Can't Patch
- Replace affected router with supported model
- Implement strict firewall rules blocking access to router management interface from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface or attempt to access form2alg.cgi endpointCheck Version:
Check router web interface or use nmap/router scanning toolsVerify Fix Applied:
Verify firmware version is updated beyond vulnerable version and test endpoint access📡 Detection & Monitoring
Log Indicators:
- POST requests to /form2alg.cgi from unauthenticated sources
- Unusual configuration changes in router logs
Network Indicators:
- HTTP POST traffic to router IP on port 80/443 targeting form2alg.cgi
SIEM Query:
source_ip=* AND dest_port IN (80,443) AND http_method=POST AND uri_path="/form2alg.cgi"