CVE-2009-2256 in DG632
Summary
by MITRE
The administrative web interface on the Netgear DG632 with firmware 3.4.0_ap allows remote attackers to cause a denial of service (web outage) via an HTTP POST request to cgi-bin/firmwarecfg.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2009-2256 affects the Netgear DG632 broadband router running firmware version 3.4.0_ap and specifically targets its administrative web interface. This issue represents a critical security flaw that enables remote attackers to execute a denial of service attack against the device's web management interface. The vulnerability stems from insufficient input validation within the firmware's handling of HTTP POST requests, creating an exploitable condition that can be leveraged by malicious actors without requiring authentication or physical access to the device.
The technical implementation of this vulnerability occurs through the cgi-bin/firmwarecfg endpoint which processes incoming HTTP POST requests. When a malformed or specially crafted POST request is sent to this specific URI, the router's web server fails to properly validate the input data before processing it. This lack of proper input sanitization allows the attacker to send malicious payloads that cause the web interface to crash or become unresponsive, effectively rendering the administrative interface unavailable to legitimate users. The vulnerability is classified as a buffer overflow or input validation flaw, which falls under CWE-121, and represents a classic example of improper input validation that can lead to system instability and service disruption.
The operational impact of this vulnerability extends beyond simple service interruption, as it can be exploited to completely disable the router's administrative capabilities for an extended period. Network administrators who rely on the web interface for configuration management, monitoring, and troubleshooting would find themselves unable to access critical management functions until the device is manually rebooted or the firmware is updated. This type of denial of service attack can be particularly damaging in enterprise environments where network reliability is paramount, as it can affect network connectivity and management capabilities for all devices connected to the router. The vulnerability demonstrates how embedded systems with web interfaces can become attack vectors when proper input validation mechanisms are not implemented, aligning with ATT&CK technique T1499.100 which covers network denial of service attacks.
Mitigation strategies for CVE-2009-2256 should include immediate firmware updates from Netgear to address the input validation flaw, network segmentation to isolate affected devices, and implementation of network access controls to restrict access to the administrative interface. Organizations should also consider deploying intrusion detection systems that can monitor for suspicious HTTP POST requests to the affected endpoint, as well as implementing regular security assessments of network infrastructure devices. The vulnerability highlights the importance of secure coding practices in embedded systems and the need for proper input validation mechanisms in web applications running on network devices, as recommended by OWASP Top 10 and NIST guidelines for embedded system security.