CVE-2023-41219 in DIR-3040
Summary
by MITRE • 05/03/2024
D-Link DIR-3040 prog.cgi SetWanSettings Stack-Based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DIR-3040 routers. Authentication is required to exploit this vulnerability.
The specific flaw exists within the prog.cgi binary, which handles HNAP requests made to the lighttpd webserver listening on TCP ports 80 and 443. The issue results from the lack of proper validation of a user-supplied string before copying it to a fixed-size stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-21619.
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Analysis
by VulDB Data Team • 05/15/2025
The CVE-2023-41219 vulnerability represents a critical stack-based buffer overflow in the D-Link DIR-3040 router's prog.cgi component, which operates as part of the lighttpd webserver infrastructure. This vulnerability resides within the HNAP (Home Network Administration Protocol) request handling mechanism, making it particularly dangerous as it can be exploited through network-adjacent attackers who can send crafted HTTP requests to the router's web interface. The vulnerability specifically affects TCP ports 80 and 443 where the lighttpd server listens for incoming connections, creating a direct attack surface for remote exploitation. The flaw stems from inadequate input validation within the prog.cgi binary, which processes administrative requests from users attempting to configure WAN settings through the web management interface. This represents a classic buffer overflow vulnerability that falls under CWE-121, stack-based buffer overflow, where user-supplied data is copied into a fixed-size buffer without proper bounds checking, leading to memory corruption and potential code execution.
The technical exploitation of this vulnerability requires an attacker to send specially crafted HNAP requests that contain overly long strings to the prog.cgi handler, causing the stack buffer to overflow and overwrite adjacent memory locations. Since the affected router is running with root privileges, successful exploitation would allow an attacker to execute arbitrary code with the highest level of system privileges, effectively compromising the entire device. The vulnerability's remote code execution capability means that even without physical access to the device, an attacker who can reach the router's network interface can potentially gain complete control over the network infrastructure. The requirement for authentication to exploit this vulnerability does not mitigate the risk significantly, as credentials can often be obtained through social engineering, credential reuse attacks, or by exploiting other vulnerabilities within the network ecosystem. This vulnerability demonstrates the importance of proper input validation and the dangers of stack-based buffer overflows in embedded systems, where the attack surface is often limited but the impact of successful exploitation can be severe.
The operational impact of CVE-2023-41219 extends beyond simple device compromise, as it enables attackers to establish persistent access points within the network infrastructure, potentially allowing for further reconnaissance, lateral movement, and data exfiltration. Once compromised, the router can serve as a pivot point for attacking other devices on the local network, or attackers can use it to create backdoors for continued access. The vulnerability also highlights the risks associated with embedded devices that lack proper memory protection mechanisms, as the stack-based nature of the overflow makes it particularly susceptible to exploitation through techniques like return-oriented programming or direct code injection. Network administrators should consider this vulnerability as part of broader security assessments, particularly in environments where D-Link DIR-3040 routers are deployed, as these devices often serve as critical network gateways. The vulnerability's classification as a remote code execution flaw aligns with ATT&CK technique T1059.007 for command and scripting interpreter, as successful exploitation would allow attackers to execute arbitrary commands on the affected system.
Mitigation strategies for CVE-2023-41219 should include immediate firmware updates from D-Link, as the vendor has likely released patches addressing the buffer overflow issue. Network segmentation and access control measures should be implemented to limit the attack surface, particularly by restricting access to the router's web interface to trusted network segments only. Additional protective measures include implementing network monitoring to detect unusual traffic patterns or attempts to access the router's administrative interface, as well as enforcing strong authentication mechanisms including multi-factor authentication where possible. System administrators should also consider disabling unnecessary services and ports, particularly if the router is not actively used for web-based management. The vulnerability underscores the importance of regular security assessments for embedded network devices, as these systems often receive less frequent updates than enterprise-grade equipment. Organizations should also maintain detailed inventories of all network devices, including embedded routers and switches, to ensure comprehensive vulnerability management and timely patch deployment across all network infrastructure components.