CVE-2018-18291 in RT-AC58U
Summary
by MITRE
A cross site scripting (XSS) vulnerability on ASUS RT-AC58U 3.0.0.4.380_6516 devices allows remote attackers to inject arbitrary web script or HTML via Advanced_ASUSDDNS_Content.asp, Advanced_WSecurity_Content.asp, Advanced_Wireless_Content.asp, Logout.asp, Main_Login.asp, MobileQIS_Login.asp, QIS_wizard.htma, YandexDNS.asp, ajax_status.xml, apply.cgi, clients.asp, disk.asp, disk_utility.asp, or internet.asp.
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Analysis
by VulDB Data Team • 04/02/2020
This cross site scripting vulnerability exists in ASUS RT-AC58U routers running firmware version 3.0.0.4.380_6516 and represents a critical security flaw that allows remote attackers to execute malicious scripts within the context of the victim's browser. The vulnerability stems from insufficient input validation and output encoding mechanisms in multiple web interface components, specifically targeting pages that handle user-supplied data without proper sanitization. The affected files include Advanced_ASUSDDNS_Content.asp, Advanced_WSecurity_Content.asp, Advanced_Wireless_Content.asp, Logout.asp, Main_Login.asp, MobileQIS_Login.asp, QIS_wizard.htma, YandexDNS.asp, ajax_status.xml, apply.cgi, clients.asp, disk.asp, disk_utility.asp, and internet.asp, indicating a widespread issue across the router's administrative web interface.
The technical exploitation of this vulnerability occurs through the injection of malicious scripts into web forms or parameters that are subsequently rendered without proper sanitization. Attackers can leverage this flaw to perform session hijacking, steal administrative credentials, redirect users to malicious websites, or execute arbitrary commands on the affected devices. The vulnerability is classified as CWE-79 - Cross-site Scripting, which is a well-documented weakness in web applications that allows attackers to inject client-side scripts into web pages viewed by other users. This particular implementation flaw demonstrates poor input validation practices where user-controllable data is directly embedded into web responses without appropriate encoding or filtering mechanisms.
The operational impact of this vulnerability extends beyond simple script injection, as it provides attackers with a potential foothold for more sophisticated attacks within the network. An attacker who successfully exploits this vulnerability could gain administrative access to the router, potentially compromising the entire network infrastructure. The attack surface is particularly concerning given that these administrative pages are designed to handle sensitive configuration data and authentication information. The vulnerability affects the router's web-based management interface, which is typically accessible from within the local network or potentially exposed to external networks through misconfigured port forwarding rules.
Mitigation strategies should focus on implementing proper input validation and output encoding across all web interface components, with particular attention to the identified vulnerable files. Organizations should immediately update to the latest firmware version provided by ASUS, as this vulnerability was likely addressed in subsequent releases. Network segmentation and access control measures should be implemented to limit exposure of the router's administrative interface to trusted users only. Additionally, implementing web application firewalls and regular security assessments of network devices can help detect and prevent exploitation attempts. The vulnerability also highlights the importance of following secure coding practices such as those outlined in the OWASP Top Ten and NIST Cybersecurity Framework, which emphasize the need for proper input validation and output encoding to prevent injection attacks. The ATT&CK framework categorizes this as a web application attack vector, specifically related to credential access and privilege escalation through compromised administrative interfaces.