CVE-2024-9913: D-Link DIR-619L Buffer Overflow Flaw

CVE-2024-9913 Overview

CVE-2024-9913 is a buffer overflow vulnerability in the D-Link DIR-619L B1 router running firmware version 2.06. The flaw resides in the formSetRoute function within /goform/formSetRoute, where the curTime argument is not properly validated before being copied into a fixed-size buffer. Attackers can trigger the condition remotely over the network with low privileges, leading to memory corruption on the device. The exploit details have been publicly disclosed, increasing the risk of opportunistic exploitation against exposed devices. The D-Link DIR-619L B1 is an end-of-life consumer router, and no vendor patch is expected.

Critical Impact
Remote attackers with low-privileged authenticated access can corrupt router memory via the curTime parameter, potentially achieving code execution or persistent denial of service on affected D-Link DIR-619L B1 devices.

Affected Products

D-Link DIR-619L B1 hardware revision
D-Link DIR-619L firmware version 2.06b1
End-of-life D-Link consumer router deployments exposing the web management interface

Discovery Timeline

2024-10-13 - CVE-2024-9913 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-9913

Vulnerability Analysis

The vulnerability is a classic buffer overflow classified under [CWE-120] (Buffer Copy without Checking Size of Input). The affected function formSetRoute handles HTTP POST requests to /goform/formSetRoute, a routing configuration endpoint on the router's web administration interface. The curTime argument supplied by the client is copied into a stack or heap buffer without a length check. Supplying an oversized value overwrites adjacent memory, including return addresses or control structures. On MIPS-based D-Link routers, this class of flaw typically enables arbitrary code execution when combined with knowledge of the firmware layout.

Root Cause

The root cause is missing bounds validation on attacker-controlled input before invocation of an unsafe memory copy operation such as strcpy or sprintf inside formSetRoute. The web server binary trusts the length of the curTime HTTP parameter and writes it directly into a fixed-size destination buffer.

Attack Vector

An attacker sends a crafted HTTP request to the /goform/formSetRoute endpoint with an oversized curTime parameter. The attack requires network reachability to the router's management interface and low-privileged authentication. Devices exposing the web interface to the WAN are directly reachable; devices restricted to the LAN require an attacker on the local network or a chained cross-site request. Successful exploitation results in memory corruption, denial of service, or potentially remote code execution on the router with the privileges of the httpd process. Full technical documentation is available in the GitHub Vulnerability Documentation and VulDB entry #280241.

Detection Methods for CVE-2024-9913

Indicators of Compromise

HTTP POST requests to /goform/formSetRoute containing abnormally long curTime parameter values, particularly exceeding a few hundred bytes
Unexpected reboots, crashes, or unresponsiveness of the router web administration interface
Unauthorized changes to routing tables, DNS settings, or firmware configuration on DIR-619L devices
Outbound connections from the router to unknown hosts, indicating potential post-exploitation implant activity

Detection Strategies

Deploy network intrusion detection signatures to alert on HTTP requests targeting /goform/formSetRoute with curTime values exceeding a defined byte threshold
Inspect web server access logs on the router where available for repeated POST requests to the formSetRoute endpoint from a single source
Monitor for authenticated sessions originating from unexpected internal or external IP addresses accessing router administration URLs

Monitoring Recommendations

Enable perimeter logging of any inbound traffic to router management ports (typically TCP/80 or TCP/443) from untrusted networks
Baseline normal administrative activity to the DIR-619L web interface and alert on statistical anomalies in request size or frequency
Track DHCP and ARP tables for the presence of legacy DIR-619L devices to maintain an accurate asset inventory of vulnerable hardware

How to Mitigate CVE-2024-9913

Immediate Actions Required

Disable remote (WAN-side) administration on the DIR-619L web interface immediately
Restrict LAN-side access to the router administration interface to a dedicated management VLAN or specific administrative hosts
Change default and existing administrative credentials on the DIR-619L to strong, unique values to limit low-privilege attackers from reaching the vulnerable endpoint
Plan replacement of affected DIR-619L B1 hardware, as the device is end-of-life and unlikely to receive a vendor patch

Patch Information

No vendor patch is currently available. The D-Link DIR-619L B1 running firmware 2.06 is an end-of-life product. Consult the D-Link Official Website for the current end-of-life policy and recommended replacement models. Organizations should treat replacement of the affected hardware as the definitive remediation.

Workarounds

Place affected routers behind an upstream firewall that blocks external access to TCP/80 and TCP/443 on the device
Segment DIR-619L devices onto isolated network segments with no direct access from user or guest networks
Deploy a web application firewall or reverse proxy that inspects and drops HTTP requests to /goform/formSetRoute containing oversized parameters
Replace affected devices with a supported router model that receives active firmware security updates

bash

# Example iptables rule to block external access to router management interface
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP

# Restrict management access to a specific admin host on the LAN
iptables -A FORWARD -p tcp -s <admin_host_ip> -d <router_ip> --dport 80 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP