CVE-2025-13190
📋 TL;DR
A remote stack-based buffer overflow vulnerability in D-Link DIR-816L routers allows attackers to execute arbitrary code by manipulating the 'en' parameter in the scandir_main function. This affects D-Link DIR-816L routers running firmware version 2_06_b09_beta. The vulnerability is particularly dangerous as these products are no longer supported by the vendor.
💻 Affected Systems
- D-Link DIR-816L
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, persistence installation, and lateral movement to other network devices.
Likely Case
Remote code execution allowing attackers to gain control of the router, intercept network traffic, and use it as a pivot point for further attacks.
If Mitigated
Limited impact if device is isolated from internet and strict network segmentation is in place.
🎯 Exploit Status
Public exploit documentation exists in GitHub repository. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: N/A
Vendor Advisory: https://www.dlink.com/
Restart Required: No
Instructions:
No official patch available as product is end-of-life. Consider replacement with supported hardware.
🔧 Temporary Workarounds
Block Access to Vulnerable Endpoint
linuxUse firewall rules to block access to /portal/__ajax_exporer.sgi endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/portal/__ajax_exporer.sgi" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 443 -m string --string "/portal/__ajax_exporer.sgi" --algo bm -j DROP
Disable Web Interface
allDisable the router's web management interface if not needed
Access router admin panel -> Administration -> Management -> Disable Remote Management
🧯 If You Can't Patch
- Isolate affected routers in separate VLAN with strict firewall rules
- Implement network monitoring for exploitation attempts and anomalous traffic
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login -> Tools -> System -> Firmware InformationCheck Version:
curl -s http://router-ip/ | grep -i firmwareVerify Fix Applied:
Test if /portal/__ajax_exporer.sgi endpoint is accessible and responds to crafted requests📡 Detection & Monitoring
Log Indicators:
- Multiple requests to /portal/__ajax_exporer.sgi with long parameter values
- Unusual process execution or memory errors in system logs
Network Indicators:
- HTTP POST requests to /portal/__ajax_exporer.sgi with oversized 'en' parameter
- Unusual outbound connections from router
SIEM Query:
source="router_logs" AND url="/portal/__ajax_exporer.sgi" AND (param_length>100 OR status_code=500)🔗 References
- https://github.com/scanleale/IOT_sec/blob/main/DIR-816L%20stack%20overflow(scandir.sgi).pdf
- https://vuldb.com/?ctiid.332479
- https://vuldb.com/?id.332479
- https://vuldb.com/?submit.685541
- https://www.dlink.com/
- https://github.com/scanleale/IOT_sec/blob/main/DIR-816L%20stack%20overflow(scandir.sgi).pdf
