CVE-2011-0746 in O2 DSL Router Classic
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in Forms/PortForwarding_Edit_1 on the ZyXEL O2 DSL Router Classic allows remote attackers to hijack the authentication of administrators for requests that insert cross-site scripting (XSS) sequences via the PortRule_Name parameter.
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Analysis
by VulDB Data Team • 01/17/2018
The CVE-2011-0746 vulnerability represents a critical cross-site request forgery flaw discovered in the ZyXEL O2 DSL Router Classic device, specifically within the Forms/PortForwarding_Edit_1 component. This vulnerability exposes the router's administrative interface to sophisticated attack vectors that can compromise network security through unauthorized administrative actions. The flaw manifests when legitimate administrative sessions are hijacked by malicious actors who can inject cross-site scripting sequences into the PortRule_Name parameter, effectively bypassing authentication mechanisms and enabling unauthorized modifications to port forwarding rules.
The technical implementation of this vulnerability stems from inadequate validation and sanitization of user input within the router's web-based administration interface. When administrators interact with the port forwarding configuration page, the system fails to properly authenticate and validate the source of requests containing the PortRule_Name parameter. This absence of proper CSRF protection tokens or session validation mechanisms allows remote attackers to craft malicious requests that appear to originate from authenticated administrative sessions. The vulnerability specifically targets the administrative interface of the ZyXEL O2 DSL Router Classic, which operates on a web server framework that does not adequately enforce request integrity checks.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it enables attackers to inject malicious cross-site scripting payloads that can persist within the router's configuration. This creates a persistent threat vector where attackers can establish backdoors or redirect traffic through compromised port forwarding rules. The combination of CSRF and XSS capabilities within a single vulnerability creates a particularly dangerous attack scenario where an attacker can not only modify administrative settings but also potentially execute arbitrary code within the router's environment. The vulnerability affects the router's ability to maintain secure administrative sessions and can result in complete network compromise through unauthorized rule modifications.
Security professionals should note that this vulnerability aligns with CWE-352, which specifically addresses cross-site request forgery weaknesses in web applications. The flaw also demonstrates characteristics consistent with ATT&CK technique T1071.004, which involves application layer protocol manipulation through web application vulnerabilities. Organizations should implement immediate mitigations including firmware updates from ZyXEL, network segmentation to isolate affected devices, and monitoring for suspicious administrative activities. The vulnerability highlights the critical importance of proper input validation and authentication mechanisms in embedded web applications, particularly those handling administrative functions in network infrastructure devices. Given the prevalence of such vulnerabilities in consumer-grade networking equipment, this case underscores the necessity for robust security testing and regular firmware updates in IoT and networking devices.