CVE-2015-5991 in Philippine Long Distance Telephone SpeedSurf 504AN
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in form2WlanSetup.cgi on Philippine Long Distance Telephone (PLDT) SpeedSurf 504AN devices with firmware GAN9.8U26-4-TX-R6B018-PH.EN and Kasda KW58293 devices allows remote attackers to hijack the authentication of administrators for requests that perform setup operations, as demonstrated by modifying network settings.
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Analysis
by VulDB Data Team • 11/08/2024
The CVE-2015-5991 vulnerability represents a critical cross-site request forgery flaw affecting PLDT SpeedSurf 504AN and Kasda KW58293 wireless broadband routers. This vulnerability resides in the form2WlanSetup.cgi web interface component of these devices, specifically targeting firmware versions GAN9.8U26-4-TX-R6B018-PH.EN and related configurations. The flaw enables remote attackers to manipulate administrative functions without legitimate authentication, effectively allowing unauthorized modification of network configurations through forged requests. The vulnerability demonstrates a fundamental failure in the web application's request validation mechanisms, where the system fails to properly verify the authenticity of incoming requests originating from authenticated administrative sessions.
The technical implementation of this CSRF vulnerability stems from the absence of proper anti-CSRF token validation within the form2WlanSetup.cgi interface. When administrators interact with the wireless network setup functions, the system should validate that requests originate from legitimate administrative sessions through the use of unique, unpredictable tokens. However, the affected devices lack this crucial validation mechanism, allowing attackers to craft malicious web pages or exploit existing network traffic to submit forged requests that appear to come from authenticated administrators. This weakness directly violates the principle of least privilege and authentication integrity, as the system cannot distinguish between legitimate administrative operations and maliciously crafted requests.
The operational impact of this vulnerability extends beyond simple configuration changes, as it provides attackers with complete administrative control over the affected network infrastructure. An attacker could potentially modify DNS settings, alter firewall rules, change administrator passwords, or disable network services entirely, effectively compromising the entire network security posture. The vulnerability is particularly dangerous because it affects consumer-grade wireless routers deployed in residential and small business environments, where network administrators may not implement additional security controls beyond the device's built-in protections. This creates a significant risk for unauthorized network access and potential data exfiltration, as the compromised devices become entry points for broader network infiltration attempts.
The vulnerability aligns with CWE-352, which specifically addresses Cross-Site Request Forgery weaknesses in web applications, and demonstrates characteristics consistent with ATT&CK technique T1566.001 for Initial Access through spearphishing attachments. The lack of proper CSRF protection in the device's web interface creates a persistent security gap that can be exploited by attackers with minimal technical expertise. Organizations should implement immediate mitigations including firmware updates from manufacturers, network segmentation to isolate affected devices, and monitoring for unauthorized configuration changes. The vulnerability also highlights the importance of secure coding practices and proper input validation in embedded web applications, as recommended by OWASP Top 10 security guidelines. Device manufacturers should ensure that all web interfaces include robust anti-CSRF token mechanisms and proper session management controls to prevent such vulnerabilities from occurring in future deployments.