CVE-2024-9915 Overview
CVE-2024-9915 is a buffer overflow vulnerability in the D-Link DIR-619L B1 router running firmware version 2.06. The flaw resides in the formVirtualServ function of the /goform/formVirtualServ endpoint. Attackers manipulate the curTime argument to overflow a fixed-size buffer, corrupting adjacent memory. The vulnerability is remotely exploitable and the exploit details have been publicly disclosed. The weakness is classified under CWE-120, Buffer Copy without Checking Size of Input.
Critical Impact
Remote attackers with low-level authentication can trigger memory corruption in the router's web management interface, enabling denial of service and potential arbitrary code execution on the device.
Affected Products
- D-Link DIR-619L Router, Hardware Revision B1
- D-Link DIR-619L Firmware version 2.06
- Legacy end-of-life D-Link consumer routers exposing /goform/ endpoints
Discovery Timeline
- 2024-10-13 - CVE-2024-9915 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2024-9915
Vulnerability Analysis
The vulnerability affects the virtual server configuration handler in the DIR-619L web management interface. When a request is submitted to /goform/formVirtualServ, the formVirtualServ function reads the curTime parameter directly from user input. The function copies this value into a fixed-size stack buffer without validating its length.
Attackers submit an oversized curTime value to overflow the destination buffer and overwrite adjacent stack data, including saved return addresses. On MIPS-based D-Link devices, this class of overflow commonly leads to control of the program counter through return-oriented programming. Successful exploitation results in denial of service or arbitrary code execution within the router's HTTP daemon context.
Root Cause
The root cause is missing bounds checking on attacker-controlled input before a memory copy operation. The formVirtualServ handler trusts the length of the curTime HTTP parameter and passes it to an unsafe string operation such as strcpy or sprintf. This pattern is characteristic of legacy D-Link firmware, where CGI handlers process form data without validating field sizes.
Attack Vector
Exploitation requires network access to the router's HTTP management interface and low-privilege authentication. An attacker sends a crafted POST request to /goform/formVirtualServ with an oversized curTime parameter. The request triggers the overflow inside the embedded web server process, typically boa or httpd on D-Link firmware. Devices exposing the management interface to the WAN are directly reachable from the internet. LAN-adjacent attackers, including malicious guests on Wi-Fi networks, can exploit the flaw without WAN exposure.
The vulnerability is documented in the GitHub Vulnerability Report and tracked as VulDB #280243.
Detection Methods for CVE-2024-9915
Indicators of Compromise
- POST requests to /goform/formVirtualServ containing unusually long curTime parameter values, typically exceeding 256 bytes
- Unexpected reboots or crashes of the router's HTTP daemon following inbound HTTP traffic
- New or modified virtual server (port forwarding) entries that do not match administrator configuration
- Outbound connections from the router to unfamiliar hosts, indicating potential post-exploitation activity
Detection Strategies
- Inspect HTTP request logs on upstream network devices for POST bodies targeting /goform/formVirtualServ with abnormal payload sizes
- Deploy network intrusion detection signatures that flag curTime parameter lengths exceeding expected values in D-Link management traffic
- Monitor router uptime and syslog output for repeated crashes of the web management service
Monitoring Recommendations
- Centralize router syslog output to a SIEM and alert on repeated HTTP daemon restarts
- Track configuration drift on DIR-619L devices, including unauthorized virtual server rules and DNS changes
- Baseline outbound network flows from router management interfaces and alert on deviations
How to Mitigate CVE-2024-9915
Immediate Actions Required
- Disable remote (WAN-side) HTTP and HTTPS management on all DIR-619L devices
- Restrict LAN management access to a dedicated administrative VLAN or trusted host list
- Rotate the router administrator password and disable any default accounts
- Inventory all DIR-619L B1 devices running firmware 2.06 and plan replacement, as this model is end-of-life
Patch Information
D-Link DIR-619L is an end-of-life product. No vendor patch has been published for CVE-2024-9915. Consult the D-Link Official Website for current end-of-life notices and replacement guidance. Organizations should replace affected units with a supported router platform that receives active security updates.
Workarounds
- Place the router behind a network firewall that blocks inbound access to TCP ports 80 and 443 on the WAN interface
- Segment the router's management interface from user and IoT networks using VLANs
- Replace the device with a currently supported model, since no firmware fix is available for this end-of-life hardware
- Disable UPnP and any unused services that expose the /goform/ handlers
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
