CVE-2005-2916 in WRT54G
Summary
by MITRE
Linksys WRT54G 3.01.03, 3.03.6, 4.00.7, and possibly other versions before 4.20.7, does not verify user authentication until after an HTTP POST request has been processed, which allows remote attackers to (1) modify configuration using restore.cgi or (2) upload new firmware using upgrade.cgi.
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Analysis
by VulDB Data Team • 06/10/2019
The vulnerability identified as CVE-2005-2916 affects Linksys WRT54G router firmware versions 3.01.03, 3.03.6, 4.00.7, and potentially other versions prior to 4.20.7. This represents a critical authentication bypass flaw that fundamentally undermines the security model of the affected network devices. The issue stems from a design flaw in the web-based administration interface where the system processes HTTP POST requests before validating user credentials, creating a window of opportunity for unauthorized modifications.
This authentication verification flaw falls under the category of CWE-285, which addresses improper authorization in software systems. The vulnerability specifically targets the web interface components restore.cgi and upgrade.cgi, which are critical administrative functions for router configuration and firmware management. Attackers can exploit this weakness to execute unauthorized configuration changes or firmware upgrades without proper authentication, effectively compromising the entire network infrastructure. The timing of the authentication check creates a race condition where malicious actors can submit requests that modify system parameters or upload malicious firmware before the system validates their identity.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with complete control over the affected routers. When attackers can modify configuration settings through restore.cgi, they gain the ability to alter network parameters, change administrator passwords, disable security features, or redirect network traffic to malicious endpoints. The firmware upload capability via upgrade.cgi presents an even more severe threat, as it allows attackers to install malicious firmware that can persistently compromise the device and potentially provide backdoor access to the entire network. This vulnerability directly aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1547.001 for registry run keys, as compromised devices can be used to establish persistent access and execute malicious commands.
The security implications of this vulnerability are particularly concerning given the widespread deployment of Linksys WRT54G routers in both residential and small business environments. These devices often serve as the primary gateway for network traffic and may control critical network functions without proper authentication safeguards. Organizations and individuals relying on these vulnerable devices face significant risks including data interception, network disruption, and potential lateral movement within compromised networks. The vulnerability demonstrates a fundamental flaw in the security architecture of the affected firmware, where the principle of least privilege is violated by allowing potentially destructive operations to proceed without proper authentication verification.
Mitigation strategies for this vulnerability require immediate firmware updates to versions 4.20.7 or later, where the authentication verification has been properly implemented before processing administrative requests. Network administrators should also consider implementing additional security controls such as network segmentation, monitoring for unauthorized firmware uploads, and regular security assessments of network devices. The vulnerability highlights the importance of proper input validation and authentication flow design in embedded systems and web applications, emphasizing the need for security by design principles. Organizations should also implement network access controls to limit administrative access to these devices and consider using network monitoring tools to detect suspicious activities related to firmware updates or configuration changes. This vulnerability serves as a reminder of the critical importance of proper authentication implementation in network infrastructure devices and the potential consequences of failing to validate user credentials before processing privileged operations.