CVE-2017-8877 in RT-AC
Summary
by MITRE
ASUS RT-AC* and RT-N* devices with firmware through 3.0.0.4.380.7378 allow JSONP Information Disclosure such as the SSID.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 09/25/2020
The vulnerability identified as CVE-2017-8877 affects ASUS RT-AC and RT-N series routers running firmware versions up to 3.0.0.4.380.7378, representing a critical information disclosure flaw that exposes sensitive network configuration data through improper JSONP implementation. This vulnerability resides within the web-based management interface of these networking devices, specifically targeting the JSONP (JSON with Padding) functionality that is commonly used for cross-domain data retrieval. The flaw allows remote attackers to extract sensitive information including the Service Set Identifier or SSID of the wireless network without requiring authentication, effectively compromising the network's foundational security parameters.
The technical implementation of this vulnerability stems from the improper handling of JSONP requests within the router's web interface, where the device fails to properly validate or sanitize incoming requests before returning sensitive configuration data. This misconfiguration creates a path for attackers to leverage the JSONP mechanism to bypass normal access controls and extract the SSID information through crafted cross-domain requests. The vulnerability specifically impacts the web management portal that administrators use to configure device settings, making it a prime target for reconnaissance activities. The JSONP implementation in these devices lacks proper origin validation and input sanitization, allowing attackers to manipulate the response format and extract data that should remain protected within the device's internal configuration space.
From an operational perspective, this vulnerability poses significant risks to network security as the SSID information serves as the first piece of information attackers need for targeted network compromise. The exposure of wireless network identifiers enables attackers to conduct more sophisticated attacks including social engineering campaigns, targeted wireless network infiltration, and protocol-specific attacks against the discovered network. The impact extends beyond simple information disclosure as it provides attackers with the foundation for further reconnaissance and potentially leads to more severe compromises of the entire network infrastructure. Network administrators who rely on the confidentiality of their wireless network identifiers face increased risk of targeted attacks, especially when combined with other reconnaissance activities that may be conducted in parallel.
The vulnerability aligns with CWE-200 (Information Exposure) and represents a specific implementation flaw that violates secure coding practices for web applications. According to ATT&CK framework, this vulnerability maps to T1046 (Network Service Scanning) and T1592 (Gather Victim Host Information) as attackers can use this information to build more targeted attack strategies. The lack of proper input validation and output sanitization in the JSONP implementation creates an attack surface that allows for unauthorized data extraction from a device that should maintain strict access controls. Organizations should consider implementing network segmentation and additional monitoring to detect unauthorized access attempts to these devices, while also recognizing that the vulnerability exists at the application layer of the device's web interface. The recommended mitigation approach involves immediate firmware updates to versions that address the JSONP implementation flaw, along with network-level controls to restrict access to the device management interfaces from untrusted networks.
This vulnerability demonstrates the importance of proper secure coding practices in embedded networking devices, where the web interfaces often become attack vectors due to insufficient validation and sanitization of user inputs. The flaw highlights the need for comprehensive security testing of web applications within network infrastructure devices, particularly those that handle sensitive configuration data. Organizations should prioritize patch management for these devices and implement monitoring solutions to detect unusual access patterns to network device management interfaces. The vulnerability also underscores the risks associated with legacy firmware implementations and the importance of maintaining current security patches for networking infrastructure components that are often overlooked in security assessments.