CVE-2006-3929 in Prestige 660H-61
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Forms/rpSysAdmin script on the Zyxel Prestige 660H-61 ADSL Router running firmware 3.40(PT.0)b32 allows remote attackers to inject arbitrary web script or HTML via hex-encoded values in the a parameter.
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Analysis
by VulDB Data Team • 01/10/2025
The CVE-2006-3929 vulnerability represents a critical cross-site scripting flaw in the Zyxel Prestige 660H-61 ADSL router's administrative interface. This vulnerability exists within the Forms/rpSysAdmin script and specifically affects firmware version 3.40(PT.0)b32, making it a significant security concern for network administrators who rely on this particular hardware model. The vulnerability stems from insufficient input validation and sanitization mechanisms within the router's web-based management interface, which fails to properly handle user-supplied data before rendering it in the browser context.
The technical exploitation of this vulnerability occurs through the manipulation of the 'a' parameter in the Forms/rpSysAdmin script, where attackers can submit hex-encoded values that bypass normal input filtering. This flaw allows remote attackers to inject arbitrary web scripts or HTML content directly into the router's administrative interface, potentially enabling malicious code execution within the context of the victim's browser session. The vulnerability is particularly dangerous because it operates at the administrative level of the router, providing attackers with privileged access to network configuration settings and potentially enabling further attacks against the internal network infrastructure.
From an operational impact perspective, this vulnerability creates multiple attack vectors for threat actors seeking to compromise network security. The remote nature of the exploit means that attackers do not require physical access to the device or network proximity to execute attacks, significantly expanding the attack surface. Successful exploitation could allow attackers to modify router settings, redirect traffic, steal administrative credentials, or establish persistent access points within the network. The vulnerability also poses risks to network integrity as it could enable man-in-the-middle attacks or facilitate the installation of backdoors on the router, potentially affecting all devices connected to the network.
Security professionals should consider this vulnerability in the context of CWE-79, which specifically addresses cross-site scripting flaws in web applications. The ATT&CK framework categorizes this type of vulnerability under T1071.004 for application layer protocols and T1566 for phishing techniques, as attackers may use this vulnerability to establish initial access or escalate privileges. The vulnerability also aligns with T1046 for network service scanning and T1059 for command and scripting interpreters, as attackers might leverage the compromised router to launch further attacks. Organizations should implement immediate mitigations including firmware updates to the latest available versions, network segmentation to isolate critical infrastructure, and enhanced monitoring of router administrative interfaces for suspicious activity.
The remediation strategy for this vulnerability involves multiple layers of defense. Primary mitigation includes updating the router firmware to a version that addresses the input validation flaw, which typically involves implementing proper sanitization of user-supplied parameters and ensuring that all input is properly encoded before being rendered in the browser context. Network administrators should also consider implementing web application firewalls that can detect and block malicious hex-encoded payloads targeting known XSS vulnerabilities. Additional protective measures include restricting administrative access to the router through firewall rules, implementing strong authentication mechanisms, and conducting regular security assessments of network infrastructure to identify similar vulnerabilities in other network devices. The vulnerability underscores the importance of maintaining up-to-date firmware and implementing robust input validation practices in network device management interfaces, as these devices often serve as primary attack vectors for network compromise attempts.