CVE-2017-6547 in RT-AC53
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in httpd in ASUS ASUSWRT on RT-AC53 3.0.0.4.380.6038 devices allows remote attackers to inject arbitrary JavaScript by requesting filenames longer than 50 characters.
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Analysis
by VulDB Data Team • 08/15/2024
The CVE-2017-6547 vulnerability represents a critical cross-site scripting flaw discovered in the ASUSWRT firmware version 3.0.0.4.380.6038 running on RT-AC53 routers. This vulnerability resides within the httpd web server component of the router's firmware and demonstrates a classic input validation weakness that has been documented under CWE-79 in the Common Weakness Enumeration catalog. The flaw specifically manifests when the web server processes filenames that exceed 50 characters in length, creating an avenue for malicious attackers to inject arbitrary JavaScript code into the router's web interface.
The technical exploitation of this vulnerability occurs through a simple yet effective method of crafting HTTP requests with excessively long filenames. When the httpd service processes these requests, it fails to properly sanitize or validate the input data before rendering it within the web interface context. This inadequate input handling creates a persistent XSS vector where attacker-controlled JavaScript code can be executed in the context of authenticated users who access the router's administration interface. The vulnerability is particularly concerning because it does not require any authentication to exploit, making it accessible to remote attackers who can leverage this flaw from outside the network perimeter.
The operational impact of CVE-2017-6547 extends beyond simple script injection, as it provides attackers with the ability to establish persistent access to the router's administrative functions. According to ATT&CK framework category T1071.004 for application layer protocol usage, this vulnerability enables adversaries to manipulate web application traffic and potentially gain full administrative control over the affected router. The compromised device could then serve as a pivot point for further network reconnaissance, allowing attackers to map internal network topology, scan for additional vulnerable devices, or establish persistent backdoors. Furthermore, the compromised router could be used to intercept and manipulate network traffic, potentially enabling man-in-the-middle attacks or DNS hijacking operations that could affect all devices connected to the network.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from ASUS to address the specific input validation flaw in the httpd component. Network administrators should also implement additional protective measures including web application firewalls that can detect and block suspicious long filename requests, network segmentation to limit the impact of potential compromise, and regular monitoring of router web interface access logs for anomalous activity. The vulnerability demonstrates the importance of input validation and output encoding practices in web applications, aligning with security best practices outlined in OWASP Top Ten and NIST cybersecurity guidelines. Organizations should also consider implementing automated patch management processes to ensure timely remediation of similar vulnerabilities across their network infrastructure, particularly in mission-critical environments where router compromise could lead to significant operational disruption or data breaches.