CVE-2023-41226 in DIR-3040
Summary
by MITRE • 05/03/2024
D-Link DIR-3040 prog.cgi SetMyDLinkRegistration 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-21652.
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Analysis
by VulDB Data Team • 05/15/2025
The CVE-2023-41226 vulnerability represents a critical stack-based buffer overflow flaw in D-Link DIR-3040 routers that exposes a remote code execution capability with root-level privileges. This vulnerability resides within the prog.cgi binary component that processes HNAP (Home Network Access Protocol) requests through the lighttpd webserver operating on standard HTTP and HTTPS ports 80 and 443. The flaw stems from insufficient input validation mechanisms that fail to properly sanitize user-supplied data before transferring it into a fixed-size stack buffer, creating a classic buffer overflow condition that can be exploited by malicious actors.
The technical implementation of this vulnerability follows the CWE-121 stack-based buffer overflow pattern where a fixed-length buffer allocated on the stack receives data without proper bounds checking. When the prog.cgi binary processes incoming HNAP requests containing maliciously crafted strings, it copies user input directly into a stack buffer without verifying that the input length remains within predetermined limits. This allows an attacker to overwrite adjacent stack memory locations, potentially corrupting the return address and control flow of the executing program. The vulnerability requires network-adjacent access and authentication credentials to exploit, making it less accessible than fully remote vulnerabilities but still highly concerning given the root-level privileges that can be achieved.
From an operational impact perspective, successful exploitation of this vulnerability enables attackers to execute arbitrary code with the highest system privileges available to the router's web server process. This means that an authenticated attacker could gain complete control over the affected D-Link DIR-3040 device, potentially using it as a foothold for further network infiltration or as a command and control node. The attack vector through the lighttpd webserver interface makes this vulnerability particularly dangerous as it can be triggered through standard web browser interactions or automated tools. The vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter execution and T1068 for exploit for privilege escalation, demonstrating how this flaw can serve as a foundation for broader compromise activities.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from D-Link to address the underlying buffer overflow condition in the prog.cgi component. Network segmentation and access controls should be implemented to limit exposure to authenticated network-adjacent attackers, while monitoring for unusual HNAP request patterns or web server activity could help detect exploitation attempts. The vulnerability's classification as a remote code execution flaw with root privileges aligns with the ATT&CK framework's emphasis on post-compromise system execution techniques, making comprehensive network monitoring essential. Additionally, implementing web application firewalls and restricting access to the router's web interface to trusted IP addresses can reduce the attack surface. Organizations should also consider disabling unnecessary services and regularly reviewing authentication mechanisms to minimize the risk of credential compromise that would be required to exploit this vulnerability.