CVE-2013-6026 in D-Link
Summary
by MITRE
The web interface on D-Link DIR-100, DIR-120, DI-624S, DI-524UP, DI-604S, DI-604UP, DI-604+, and TM-G5240 routers; Planex BRL-04R, BRL-04UR, and BRL-04CW routers; and Alpha Networks routers allows remote attackers to bypass authentication and modify settings via an xmlset_roodkcableoj28840ybtide User-Agent HTTP header, as exploited in the wild in October 2013.
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Analysis
by VulDB Data Team • 08/17/2024
The vulnerability identified as CVE-2013-6026 represents a critical authentication bypass flaw affecting multiple router models from D-Link, Planex, and Alpha Networks. This vulnerability resides within the web interface of affected networking equipment and allows remote attackers to gain unauthorized access to router configuration settings without proper authentication. The exploit leverages a specific User-Agent HTTP header named xmlset_roodkcableoj28840ybtide which serves as a trigger mechanism for bypassing the authentication layer. The vulnerability was actively exploited in the wild during October 2013, demonstrating its significance and the immediate threat it posed to network security. This type of vulnerability falls under the category of improper authentication mechanisms and aligns with CWE-287 which addresses authentication failures in software systems. The attack vector exploits the web-based management interface of routers, which typically requires proper credentials for configuration access but can be circumvented through this specific header manipulation.
The technical implementation of this vulnerability exploits a design flaw in the router's web server implementation where the system fails to properly validate the User-Agent header before processing administrative requests. When the specific xmlset_roodkcableoj28840ybtide header is present in an HTTP request, the router's authentication logic incorrectly interprets this as a legitimate administrative request rather than a potential attack vector. This flaw demonstrates poor input validation and insufficient security controls within the web interface authentication mechanism. The vulnerability essentially creates a backdoor path through which any remote attacker can access router configuration settings without requiring valid login credentials, username, or password. The exploitation process requires only sending a crafted HTTP request with the specific User-Agent header, making it particularly dangerous as it can be automated and executed at scale. This type of vulnerability directly violates the principle of least privilege and demonstrates inadequate security architecture in the affected devices.
The operational impact of CVE-2013-6026 extends far beyond simple unauthorized access, as it provides attackers with complete control over affected router configurations. Once exploited, attackers can modify network settings, change administrator passwords, disable security features, redirect traffic, and potentially establish persistent access points within the network infrastructure. The vulnerability affects a wide range of consumer and small office networking equipment, making it particularly dangerous as it could compromise thousands of devices across multiple organizations and households. Network administrators who were unaware of the vulnerability could find their networks completely compromised, leading to potential data breaches, man-in-the-middle attacks, and unauthorized network access. The impact is exacerbated by the fact that these devices are often deployed in environments where network security is not a primary concern, making them easy targets for attackers seeking to establish footholds within larger networks. This vulnerability could also enable attackers to create persistent backdoors or use the compromised devices as launching points for attacks against other network resources, aligning with tactics described in the MITRE ATT&CK framework under initial access and persistence domains.
Mitigation strategies for CVE-2013-6026 require immediate action from network administrators and device owners. The most effective approach involves applying firmware updates from the device manufacturers, as these updates typically include patches that address the authentication bypass vulnerability. Organizations should also implement network segmentation to isolate affected devices from critical network infrastructure and consider disabling web-based management interfaces where possible. Network monitoring should be enhanced to detect unusual User-Agent headers or suspicious administrative access patterns. Device hardening measures including disabling unnecessary services, changing default credentials, and implementing firewall rules to restrict access to management interfaces are essential. Security professionals should also consider implementing intrusion detection systems that can identify the specific xmlset_roodkcableoj28840ybtide User-Agent header pattern. The vulnerability highlights the importance of regular security assessments and firmware updates for network infrastructure equipment, as many of these devices remain unpatched for extended periods. Given the widespread nature of affected models, organizations should conduct comprehensive inventory assessments to identify all potentially vulnerable devices and implement layered security controls to protect against similar authentication bypass vulnerabilities.