CVE-2024-9783 in DIR-619L B1
Summary
by MITRE • 10/10/2024
A vulnerability was found in D-Link DIR-619L B1 2.06. It has been rated as critical. This issue affects the function formLogDnsquery of the file /goform/formLogDnsquery. The manipulation of the argument curTime leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 08/20/2026
The D-Link DIR-619L B1 router, specifically running firmware version 2.06, contains a critical security vulnerability within its embedded web server implementation that allows for remote code execution through buffer overflow exploitation. This flaw is located in the formLogDnsquery function found in the /goform/formLogDnsquery script, which is part of the device's CGI interface responsible for logging DNS query activities. The severity of this issue stems from the lack of proper input validation and bounds checking when processing the curTime argument passed to this function. An attacker can craft a specially designed HTTP request containing an oversized or malformed value for the curTime parameter, triggering a stack-based buffer overflow that overwrites adjacent memory structures on the device's processor.
From a technical perspective, this vulnerability represents a classic instance of improper input validation leading to memory corruption. The embedded Linux environment running on these routers typically utilizes standard C libraries where string handling functions do not automatically check for buffer boundaries. When the curTime argument exceeds the allocated stack space, it overwrites critical return addresses or function pointers. This allows an attacker to redirect the execution flow of the program, potentially executing arbitrary shellcode injected as part of the malicious payload. The presence of this vulnerability in a network-facing component like DNS logging significantly expands the attack surface, as it does not require authentication and can be triggered by any entity capable of reaching the router's management interface over the network.
The operational impact of exploiting this vulnerability is severe, potentially resulting in full compromise of the affected device. Once an attacker achieves code execution on the router, they gain control over a critical gateway node within the local network infrastructure. This position enables several malicious activities including traffic interception and man-in-the-middle attacks against all devices connected to the LAN. The compromised router can be used as a pivot point for lateral movement into internal networks, allowing access to sensitive data stored on workstations or servers behind the firewall. Furthermore, attackers may install persistent backdoors such as botnet agents like Mirai variants, turning the device into part of a larger distributed denial-of-service network. This undermines the confidentiality, integrity, and availability of both personal and corporate network resources protected by this gateway.
In terms of industry classification standards, this vulnerability aligns with CWE-120 Buffer Copy without Checking Size of Input Classic buffer overflow and CWE-78 Improper Neutralization of Special Elements used in an OS Command if the exploit leads to command injection. From a tactical perspective according to MITRE ATT&CK for IOT, this falls under T1505.003 Web Server Component Implantation or T1190 Exploit Public-Facing Application. The fact that public exploits are available significantly increases the risk level, as automated scanning tools and opportunistic attackers can easily leverage these existing proof-of-concept scripts to compromise unpatched devices at scale without requiring advanced custom development skills.
Mitigation strategies must prioritize immediate patching if a firmware update is provided by D-Link that addresses this specific buffer overflow in formLogDnsquery. In the absence of an official patch, network segmentation should be implemented to restrict access to the router's management interface from untrusted networks or public internet sources using firewall rules. Additionally, disabling unnecessary CGI services and web server features can reduce the attack surface. Administrators should also enable logging and monitor for anomalous HTTP requests containing unusually long parameters directed at /goform endpoints as an indicator of attempted exploitation. Regular vulnerability assessments and penetration testing are recommended to identify similar weaknesses in other embedded devices within the infrastructure before they can be exploited by malicious actors leveraging publicly disclosed exploits.