CVE-2023-41230 in DIR-3040
Summary
by MITRE • 05/03/2024
D-Link DIR-3040 HTTP Request Processing Referer 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 not 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-21674.
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Analysis
by VulDB Data Team • 05/03/2024
The D-Link DIR-3040 router presents a critical remote code execution vulnerability originating from improper HTTP request processing within the prog.cgi binary component. This flaw resides in the web server implementation that manages HNAP (Home Network Administration Protocol) requests through the lighttpd webserver operating on standard TCP ports 80 and 443. The vulnerability stems from inadequate input validation mechanisms that fail to properly sanitize user-supplied data before processing, creating a dangerous condition where malicious input can overwrite adjacent memory locations in the stack-based buffer allocation.
The technical implementation of this vulnerability manifests as a stack-based buffer overflow occurring within the prog.cgi binary when handling Referer headers in HTTP requests. The specific flaw involves the copying of user-provided strings into a fixed-size stack buffer without adequate bounds checking or length validation. This classic buffer overflow condition enables attackers to overwrite return addresses and execution pointers within the stack, allowing arbitrary code execution with the highest privilege level available on the device. The vulnerability operates under CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory allocations where insufficient bounds checking permits data to overwrite adjacent memory locations.
From an operational perspective, this vulnerability represents a severe security risk as it requires no authentication credentials for exploitation and can be executed by attackers within the network adjacency range of the affected device. The attack surface is particularly concerning given that many users operate these routers in home or small office environments where network segmentation may be minimal or absent. Once exploited, the vulnerability grants attackers complete control over the router's functionality with root-level privileges, potentially enabling them to modify network configurations, establish persistent backdoors, redirect traffic, or use the device as a launching point for further attacks against other networked systems.
The implications of this vulnerability extend beyond immediate device compromise, creating potential for broader network infiltration and lateral movement within targeted environments. Attackers can leverage this remote code execution capability to manipulate router settings, disable security features, or establish command and control channels through the compromised device. The ZDI-CAN-21674 identifier reflects the vulnerability's recognition within the cybersecurity community and its classification as a critical threat requiring immediate remediation. Network defenders should consider implementing mitigation strategies including network segmentation, firewall rules restricting access to TCP ports 80 and 443, and monitoring for suspicious HTTP requests containing malformed Referer headers. Additionally, the vulnerability aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript, as exploitation may involve crafting malicious HTTP requests that trigger script execution within the router's web server environment.
Mitigation strategies should prioritize immediate firmware updates from D-Link to address the underlying buffer overflow condition in prog.cgi. Network administrators should implement strict access controls limiting exposure of TCP ports 80 and 443 to authorized users only, while deploying intrusion detection systems capable of identifying suspicious HTTP request patterns that may indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper input validation and memory management practices in embedded network device software development, emphasizing the need for robust security testing throughout the software development lifecycle. Organizations should also consider implementing network monitoring solutions to detect anomalous behavior indicative of router compromise, including unexpected routing changes or unusual traffic patterns originating from compromised devices.