CVE-2024-9550 Overview
CVE-2024-9550 is a buffer overflow vulnerability in D-Link DIR-605L routers running firmware version 2.13B01 BETA. The flaw resides in the formLogDnsquery function within /goform/formLogDnsquery. An attacker can manipulate the curTime argument to overflow a fixed-size buffer, corrupting adjacent memory on the device. The vulnerability is remotely exploitable over the network and has been publicly disclosed. The DIR-605L reached end-of-life status, and D-Link is unlikely to release a patch for this device.
Critical Impact
Remote attackers with low-privilege access can trigger memory corruption in the router's web management interface, potentially leading to arbitrary code execution or denial of service on affected devices.
Affected Products
- D-Link DIR-605L router (hardware)
- D-Link DIR-605L firmware version 2.13B01 BETA
- formLogDnsquery handler in /goform/formLogDnsquery
Discovery Timeline
- 2024-10-06 - CVE-2024-9550 published to the National Vulnerability Database (NVD)
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-9550
Vulnerability Analysis
The vulnerability is a classic stack-based buffer overflow [CWE-120] in the router's web administration binary. The formLogDnsquery handler processes HTTP requests submitted to /goform/formLogDnsquery and reads the curTime parameter directly from user-controlled input. The function copies this parameter into a fixed-size buffer without validating its length, allowing an attacker to write past the buffer boundary.
Successful exploitation can overwrite adjacent stack data, including saved return addresses. On MIPS-based D-Link devices such as the DIR-605L, this typically enables control of the program counter and execution of attacker-supplied instructions. At minimum, the overflow crashes the httpd process and causes a denial of service on the management interface.
The attack requires network reachability to the router's web interface and low-level privileges, which many consumer deployments satisfy through default or weakly configured credentials.
Root Cause
The root cause is the absence of bounds checking on the curTime parameter before it is copied into a stack buffer inside formLogDnsquery. The handler trusts client-supplied input length, a common pattern in legacy embedded web servers using unsafe C string routines such as strcpy or sprintf.
Attack Vector
An attacker sends a crafted HTTP POST request to /goform/formLogDnsquery on the router's management interface with an oversized curTime value. If the interface is exposed to the WAN, exploitation is possible from the internet. On LAN-only deployments, an attacker with network access, including a rogue Wi-Fi client, can trigger the flaw. Technical details and a proof-of-concept are documented in the GitHub Vulnerability Log and the VulDB CTI Report #279348.
The vulnerability is triggered by sending an HTTP request to
/goform/formLogDnsquery with an overlong curTime parameter value.
No verified exploit code is reproduced here; refer to the linked
GitHub disclosure and VulDB report for full technical details.
Detection Methods for CVE-2024-9550
Indicators of Compromise
- HTTP POST or GET requests to /goform/formLogDnsquery containing abnormally long curTime parameter values.
- Unexpected reboots or crashes of the router's httpd process visible in system logs.
- New or unexplained inbound connections from the router to external hosts after suspicious web-admin traffic.
Detection Strategies
- Inspect network traffic for HTTP requests to /goform/formLogDnsquery with curTime values exceeding typical timestamp lengths, and alert on requests originating from untrusted network segments.
- Deploy IDS/IPS signatures that match oversized parameters on D-Link formLog* endpoints.
- Review router administration logs for repeated failed authentication attempts followed by requests to the vulnerable endpoint.
Monitoring Recommendations
- Monitor for D-Link DIR-605L devices on the network using asset inventory tools and flag any device running firmware 2.13B01 BETA.
- Track outbound traffic from consumer-grade routers for anomalies that may indicate post-exploitation activity.
- Log and alert on management-interface access from non-administrative network zones.
How to Mitigate CVE-2024-9550
Immediate Actions Required
- Disable remote (WAN-side) management on all DIR-605L devices to prevent internet-based exploitation.
- Restrict LAN-side administrative access to a dedicated management VLAN or trusted IP range.
- Rotate router administrator credentials and disable any default accounts that remain enabled.
- Plan replacement of DIR-605L hardware, as the model is end-of-life and unlikely to receive vendor patches.
Patch Information
No official vendor patch is currently listed for CVE-2024-9550. The DIR-605L is an end-of-life product line. Check the D-Link Official Website for the latest support status and firmware releases specific to your region. In the absence of a patch, replacement with a currently supported router model is the recommended long-term remediation.
Workarounds
- Block external access to TCP port 80 and 443 on the router's WAN interface at the perimeter.
- Place the router behind a network segment with an inspecting firewall that filters requests to /goform/formLogDnsquery.
- Segment IoT and guest networks away from administrative interfaces of legacy consumer routers.
# Example iptables rule on an upstream Linux gateway to block
# external access to the DIR-605L management interface
iptables -A FORWARD -d <router_ip> -p tcp --dport 80 -j DROP
iptables -A FORWARD -d <router_ip> -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
