CVE-2022-30521
📋 TL;DR
This CVE describes a critical stack-based buffer overflow vulnerability in D-Link DIR-890L router firmware that allows unauthenticated remote code execution. Attackers can exploit it by sending specially crafted HTTP requests to the LAN-side web configuration interface on port 49152. All users of affected DIR-890L router versions are vulnerable.
💻 Affected Systems
- D-Link DIR-890L Wi-Fi Router
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise allowing attackers to install persistent malware, intercept all network traffic, pivot to internal network devices, and use the router as a botnet node.
Likely Case
Router takeover enabling traffic interception, DNS hijacking, credential theft, and lateral movement to connected devices.
If Mitigated
Limited impact if router is behind firewall with restricted LAN access and proper network segmentation.
🎯 Exploit Status
Public exploit code available on GitHub repositories. Exploitation requires sending crafted HTTP requests to port 49152.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check D-Link security bulletin for latest firmware
Vendor Advisory: https://www.dlink.com/en/security-bulletin/
Restart Required: Yes
Instructions:
1. Visit D-Link support site 2. Download latest firmware for DIR-890L 3. Log into router admin interface 4. Navigate to firmware update section 5. Upload and apply new firmware 6. Reboot router
🔧 Temporary Workarounds
Block LAN Access to Router Admin
allUse firewall rules to restrict access to router's admin interface from untrusted devices
Disable Remote Administration
allEnsure router's remote administration feature is disabled
🧯 If You Can't Patch
- Replace router with supported model
- Isolate router on separate VLAN with strict access controls
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version is DIR890LA1_FW107b09.bin or earlier, you are vulnerable.Check Version:
Check router web interface at http://[router-ip]:49152 or use nmap scan on port 49152Verify Fix Applied:
Verify firmware version has been updated to a version after DIR890LA1_FW107b09.bin📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to port 49152
- Multiple failed login attempts to router interface
- Unexpected router reboots or configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic to port 49152 from unexpected sources
- DNS queries to suspicious domains from router
SIEM Query:
source_port:49152 AND (http_method:POST OR http_method:GET) AND (uri_contains:"cgibin" OR user_agent_contains:exploit)🔗 References
- https://github.com/winmt/CVE/blob/main/DIR-890L/README.md
- https://github.com/winmt/my-vuls/tree/main/DIR-890L
- https://www.dlink.com/en/security-bulletin/
- https://github.com/winmt/CVE/blob/main/DIR-890L/README.md
- https://github.com/winmt/my-vuls/tree/main/DIR-890L
- https://www.dlink.com/en/security-bulletin/
