CVE-2020-5606 in WHR-G54S
Summary
by MITRE
Cross-site scripting vulnerability in WHR-G54S firmware 1.43 and earlier allows remote attackers to inject arbitrary script via a specially crafted page.
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Analysis
by VulDB Data Team • 09/18/2020
The CVE-2020-5606 vulnerability represents a critical cross-site scripting flaw discovered in the WHR-G54S wireless router firmware version 1.43 and earlier. This vulnerability resides within the web interface of the device, which serves as the primary means for administrators and users to configure and manage the router's settings. The affected firmware versions expose a fundamental security weakness that allows remote attackers to execute malicious scripts against unsuspecting users who interact with the compromised web interface. The vulnerability specifically manifests when the router fails to properly sanitize user input submitted through web forms or URL parameters, creating an avenue for malicious code injection.
The technical exploitation of this vulnerability follows a classic XSS attack pattern where an attacker crafts a malicious payload containing script code and delivers it through a specially crafted web page or link. When a victim accesses this malicious page while authenticated to the router's web interface, the injected script executes in the victim's browser context, potentially leading to session hijacking, credential theft, or redirection to malicious sites. The flaw demonstrates a failure in input validation and output encoding mechanisms within the router's web server implementation, where user-supplied data is not adequately filtered or escaped before being rendered back to the browser. This vulnerability falls under the CWE-79 category of Cross-site Scripting, specifically representing a reflected XSS attack vector where the malicious script is reflected off the web server in response to a user request.
The operational impact of CVE-2020-5606 extends beyond simple script execution, as it provides attackers with a foothold for more sophisticated attacks within the network environment. An attacker who successfully exploits this vulnerability could potentially gain access to administrative credentials, modify router configurations, or redirect traffic through the compromised device. The remote nature of the attack means that exploitation does not require physical access to the device, making it particularly dangerous for enterprise and home network environments. The vulnerability affects not only the router's management interface but also creates potential for lateral movement within networks where the compromised device serves as a gateway, as the attacker could use the compromised router as a pivot point for further reconnaissance and attacks against internal network resources.
Mitigation strategies for CVE-2020-5606 should prioritize immediate firmware updates to version 1.44 or later, which contain patches addressing the input validation deficiencies. Network administrators should also implement additional defensive measures such as web application firewalls to detect and block malicious script payloads, and consider disabling the web management interface when not actively required. The vulnerability highlights the importance of secure coding practices and input validation in network device firmware, aligning with ATT&CK technique T1212 for exploitation of software vulnerabilities. Organizations should conduct regular firmware audits and vulnerability assessments to identify similar issues in other network infrastructure components. The security community should also consider implementing network segmentation and monitoring for suspicious traffic patterns that might indicate exploitation attempts, as the vulnerability could be leveraged as part of broader attack campaigns targeting network infrastructure devices.