CVE-2018-13022 in Mi Router 3
Summary
by MITRE
Cross-site scripting vulnerability in the API 404 page on Xiaomi Mi Router 3 version 2.22.15 allows attackers to execute arbitrary JavaScript via a modified URL path.
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Analysis
by VulDB Data Team • 04/15/2020
The vulnerability identified as CVE-2018-13022 represents a critical cross-site scripting flaw discovered in the Xiaomi Mi Router 3 firmware version 2.22.15. This issue manifests specifically within the API 404 error handling mechanism of the router's web interface, creating a pathway for malicious actors to inject and execute arbitrary JavaScript code. The vulnerability stems from insufficient input validation and output sanitization within the router's web server implementation, particularly when handling malformed URL requests that trigger the 404 error page generation. Attackers can exploit this weakness by crafting specially modified URL paths that bypass normal input filtering mechanisms, causing the router to render malicious scripts within the context of the user's browser session. This particular implementation flaw demonstrates a classic lack of proper context-aware output encoding that violates fundamental web security principles and aligns with CWE-79, which catalogs cross-site scripting vulnerabilities.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to establish persistent access to the router's administrative interface. When a user navigates to a crafted URL path, the malicious JavaScript code executes within the router's web interface context, potentially allowing attackers to steal session cookies, modify router configurations, or even escalate privileges within the device's access control system. The vulnerability's exploitation is particularly concerning because it occurs at the API level where legitimate administrative functions are handled, making it difficult for network administrators to distinguish between normal and malicious traffic patterns. This type of attack vector is categorized under ATT&CK technique T1059.007 for command and scripting interpreter, specifically targeting JavaScript execution within web browsers. The router's firmware version 2.22.15 represents a vulnerable configuration where input validation is insufficient to prevent malicious payload injection, creating a persistent threat vector that remains active as long as the device operates with the vulnerable firmware.
Mitigation strategies for this vulnerability require immediate firmware updates from Xiaomi to address the root cause of insufficient input validation within the API error handling mechanism. Network administrators should implement proactive monitoring of router web traffic to detect anomalous URL patterns that may indicate exploitation attempts, particularly focusing on unusual path parameters that could trigger the 404 handler. The implementation of Content Security Policy headers and proper output encoding mechanisms within the router's web server configuration would provide additional protection layers against such attacks. Organizations should also consider network segmentation and access control measures to limit exposure of router administrative interfaces to untrusted networks, while regular security audits of network infrastructure should include verification of firmware versions and patch status. The vulnerability highlights the importance of secure coding practices in embedded systems and demonstrates how seemingly minor flaws in error handling can create significant security risks, particularly when dealing with network infrastructure devices that require persistent access and administrative capabilities.