CVE-2025-5912
📋 TL;DR
A critical stack-based buffer overflow vulnerability in D-Link DIR-632 router firmware allows remote attackers to execute arbitrary code via specially crafted HTTP POST requests. This affects all systems running the vulnerable firmware version, particularly internet-facing routers. The product is no longer supported by the vendor, leaving users without official patches.
💻 Affected Systems
- D-Link DIR-632
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete router compromise, network traffic interception, credential theft, and lateral movement into connected networks.
Likely Case
Router takeover enabling DNS hijacking, man-in-the-middle attacks, and creation of persistent backdoors for botnet participation.
If Mitigated
Limited impact if device is behind firewall with strict inbound filtering, though internal network exposure remains.
🎯 Exploit Status
Public proof-of-concept available on GitHub. Exploitation requires sending crafted HTTP POST requests to the vulnerable endpoint.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None available
Vendor Advisory: None - product is end-of-life
Restart Required: No
Instructions:
No official patch exists. Replace affected hardware with supported equipment.
🔧 Temporary Workarounds
Disable remote management
allTurn off remote administration/management features to prevent internet-based attacks
Network segmentation
allIsolate router management interface to separate VLAN with strict access controls
🧯 If You Can't Patch
- Immediately replace affected DIR-632 routers with supported hardware
- Implement strict firewall rules blocking all inbound HTTP/HTTPS traffic to router management IP
🔍 How to Verify
Check if Vulnerable:
Check router web interface or serial console for firmware version FW103B08Check Version:
Check router web interface at http://[router-ip]/ or use serial console connectionVerify Fix Applied:
Verify router has been replaced with different model or firmware📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to router management interface
- Multiple failed buffer overflow attempts in system logs
Network Indicators:
- HTTP traffic with unusually long POST parameters to router IP
- Traffic patterns suggesting exploit payload delivery
SIEM Query:
source_ip="router_ip" AND http_method="POST" AND (uri_contains="do_file" OR content_length>threshold)🔗 References
- https://github.com/xiaobor123/vul-finds/tree/main/vul-find-dir632-dlink
- https://github.com/xiaobor123/vul-finds/tree/main/vul-find-dir632-dlink#poc
- https://vuldb.com/?ctiid.311686
- https://vuldb.com/?id.311686
- https://vuldb.com/?submit.592307
- https://www.dlink.com/
- https://github.com/xiaobor123/vul-finds/tree/main/vul-find-dir632-dlink
- https://github.com/xiaobor123/vul-finds/tree/main/vul-find-dir632-dlink#poc
