CVE-2017-5892 in RT-AC
Summary
by MITRE
ASUS RT-AC* and RT-N* devices with firmware before 3.0.0.4.380.7378 allow JSONP Information Disclosure such as a network map.
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Analysis
by VulDB Data Team • 09/26/2020
The vulnerability CVE-2017-5892 affects ASUS RT-AC and RT-N router models running firmware versions prior to 3.0.0.4.380.7378, representing a critical information disclosure flaw that exposes network topology data through JSONP endpoints. This vulnerability falls under the CWE-200 category of Information Exposure and aligns with ATT&CK technique T1046 for Network Service Scanning and T1082 for System Information Discovery. The affected devices utilize JSONP (JSON with Padding) functionality in their web interfaces without proper input validation or access controls, creating an avenue for unauthorized information retrieval.
The technical flaw stems from the improper implementation of JSONP handlers within the router's web administration interface, specifically in the network map functionality that allows external attackers to retrieve detailed network topology information. JSONP is designed to enable cross-domain data requests, but when implemented without proper security measures, it becomes a vector for information disclosure. Attackers can exploit this vulnerability by crafting malicious requests to specific endpoints that return network mapping data including device names, IP addresses, subnet configurations, and potentially other sensitive network information. The vulnerability exists because the JSONP endpoints lack authentication checks, authorization controls, and input sanitization mechanisms that would normally prevent unauthorized access to internal network data.
The operational impact of this vulnerability is significant as it provides attackers with comprehensive network mapping information that can be used for subsequent exploitation phases. An attacker who successfully exploits this vulnerability can obtain detailed knowledge of the internal network structure including device configurations, network segments, and potential attack vectors. This information disclosure enables more sophisticated attacks such as targeted exploitation of specific network devices, social engineering campaigns, or advanced persistent threat operations. The vulnerability affects not only the immediate device but also provides attackers with insights into the broader network infrastructure, potentially exposing interconnected systems and services that may be more vulnerable to exploitation. Network administrators may be unaware of this exposure since the information is typically accessed through legitimate web interface endpoints.
Mitigation strategies for this vulnerability include immediate firmware updates to version 3.0.0.4.380.7378 or later, which addresses the JSONP implementation issues and includes proper access controls. Organizations should also implement network segmentation and firewall rules to restrict access to router administration interfaces, particularly from untrusted networks. Additional protective measures include disabling JSONP functionality where possible, implementing network monitoring to detect unusual access patterns to web interfaces, and conducting regular security assessments of network infrastructure. The vulnerability demonstrates the importance of secure coding practices and proper input validation in network device software, emphasizing that even seemingly benign features like JSONP can create significant security risks when not properly implemented. Network security teams should also consider implementing intrusion detection systems that can identify attempts to access sensitive network mapping information through web interfaces.