CVE-2024-5293 in DIR-2640
Summary
by MITRE • 05/24/2024
D-Link DIR-2640 HTTP 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-2640-US routers. Authentication is not required to exploit this vulnerability.
The specific flaw exists within prog.cgi, 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 the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-21853.
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Analysis
by VulDB Data Team • 08/06/2025
The CVE-2024-5293 vulnerability represents a critical stack-based buffer overflow in D-Link DIR-2640-US routers that exposes a remote code execution risk without requiring authentication. This vulnerability resides within the prog.cgi component of the router's web server implementation, specifically when processing HNAP (Home Network Access Protocol) requests through the lighttpd web server listening on standard HTTP and HTTPS ports 80 and 443. The flaw stems from inadequate input validation mechanisms that fail to properly check the length of user-supplied data before copying it into a fixed-size stack buffer, creating a classic buffer overflow condition that can be exploited by remote attackers. This vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which is categorized under the broader category of CWE-119 Improper Access to Memory Location, making it a particularly dangerous weakness in the router's security architecture.
The technical exploitation of this vulnerability occurs when an attacker sends a specially crafted HNAP request containing excessive data in the HTTP Referer header field, which is then processed by the vulnerable prog.cgi script. The lack of proper bounds checking means that user-supplied input can overflow the predetermined stack buffer space, potentially overwriting adjacent memory locations including return addresses and control data. This allows an attacker to manipulate the program execution flow and inject malicious code that executes with the highest privilege level available to the web server process, which on these routers runs with root privileges. The absence of authentication requirements significantly increases the attack surface, as any network-adjacent attacker can exploit this vulnerability without needing to provide valid credentials, making it particularly dangerous for devices deployed in untrusted network environments.
The operational impact of this vulnerability extends beyond simple remote code execution to encompass complete system compromise and potential network infiltration. Successful exploitation enables attackers to gain full administrative control over the affected router, allowing them to modify network configurations, establish persistent backdoors, redirect traffic through malicious proxies, or use the device as a pivot point for attacking other systems within the local network. The vulnerability's classification under the MITRE ATT&CK framework would map to techniques such as T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as attackers could leverage the compromised device to maintain persistence and conduct further reconnaissance. Additionally, the vulnerability's exposure through standard web ports 80 and 443 makes it particularly attractive to automated scanning tools and botnets that continuously search for exploitable devices.
Mitigation strategies for CVE-2024-5293 should prioritize immediate firmware updates from D-Link, as this represents a critical security flaw that requires vendor-provided patches to address the underlying buffer overflow condition. Network administrators should implement network segmentation and access controls to limit exposure of these devices to untrusted networks, while also deploying intrusion detection systems that can identify suspicious HNAP request patterns or malformed Referer headers. Additional defensive measures include disabling unnecessary web services on the router, implementing strict firewall rules that restrict access to ports 80 and 443 from untrusted sources, and conducting regular network scans to identify potentially vulnerable devices. Organizations should also consider implementing network monitoring solutions that can detect anomalous traffic patterns consistent with exploitation attempts, as the vulnerability's remote nature makes it particularly susceptible to automated exploitation campaigns that target commonly deployed router models.