CVE-2017-8878 in RT-AC
Summary
by MITRE
ASUS RT-AC* and RT-N* devices with firmware before 3.0.0.4.380.7378 allow remote authenticated users to discover the Wi-Fi password via WPS_info.xml.
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Analysis
by VulDB Data Team • 09/25/2020
The vulnerability identified as CVE-2017-8878 affects ASUS RT-AC and RT-N series routers, representing a significant security flaw in the firmware implementation of these networking devices. This issue stems from improper access control mechanisms within the router's web interface, specifically in how it handles WPS information disclosure. The vulnerability impacts devices running firmware versions prior to 3.0.0.4.380.7378, making a substantial portion of deployed ASUS routers susceptible to exploitation. The flaw allows remote authenticated users to access sensitive configuration data through a specific XML file that contains Wi-Fi password information.
The technical implementation of this vulnerability resides in the router's web server component, which fails to properly validate user permissions when serving requests for WPS information. When an authenticated user accesses the WPS_info.xml file through the web interface, the system does not adequately restrict access based on user privileges or session authentication status. This misconfiguration results in the exposure of wireless network credentials, including the pre-shared key used for Wi-Fi authentication. The vulnerability operates under CWE-284 which specifically addresses improper access control, where the system grants access to resources beyond what is intended for the authenticated user. The flaw demonstrates a classic example of insufficient authorization checks in web applications, where sensitive data is accessible through predictable file paths without proper validation.
The operational impact of this vulnerability extends beyond simple credential exposure, as it provides attackers with the means to gain unauthorized access to wireless networks that are protected by the compromised router. This creates a potential attack vector for lateral movement within networks, particularly in environments where wireless access is used for critical operations. The remote nature of the vulnerability means that attackers do not need physical access to the device or network, as they can exploit this issue from anywhere on the internet. The compromise of Wi-Fi passwords can lead to complete network infiltration, allowing attackers to monitor traffic, gain access to connected devices, and potentially escalate privileges to other network resources. This vulnerability aligns with ATT&CK technique T1046 which involves discovery of network services, and T1075 which covers remote service access, as it enables unauthorized access to network infrastructure.
Mitigation strategies for CVE-2017-8878 primarily involve updating the firmware to version 3.0.0.4.380.7378 or later, which addresses the improper access control issue through proper authentication and authorization checks. Network administrators should immediately implement firmware updates across all affected devices, as the vulnerability is particularly dangerous due to its remote exploitability. Additional protective measures include disabling WPS functionality on affected routers, as this feature often introduces additional security risks beyond the scope of this specific vulnerability. The implementation of network segmentation and monitoring solutions can help detect unauthorized access attempts to router management interfaces. Security teams should also consider implementing network access control policies that restrict direct access to router management interfaces from external networks, and regularly audit router configurations to ensure that sensitive information is not exposed through web interface misconfigurations. The vulnerability serves as a reminder of the importance of proper access control implementation and the necessity of regular firmware updates to address known security flaws.