CVE-2017-12591 in DSL-N10S
Summary
by MITRE
ASUS DSL-N10S V2.1.16_APAC devices have reflected and stored cross site scripting, as demonstrated by the snmpSysName parameter.
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Analysis
by VulDB Data Team • 11/08/2019
The vulnerability identified as CVE-2017-12591 affects ASUS DSL-N10S V2.1.16_APAC wireless routers and similar devices, representing a critical security flaw in network infrastructure equipment. This vulnerability manifests as both reflected and stored cross-site scripting (XSS) vulnerabilities, which are particularly dangerous in network devices due to their privileged access and potential for widespread impact. The specific vector involves the snmpSysName parameter, which is commonly used for system identification and management within network monitoring protocols. When an attacker crafts malicious input containing script code and submits it through this parameter, the device fails to properly sanitize the input before processing or storing it, creating opportunities for malicious code execution.
The technical flaw in this vulnerability stems from inadequate input validation and output encoding mechanisms within the web interface of the affected ASUS devices. The reflected XSS component occurs when user input is immediately reflected back in the application response without proper sanitization, allowing attackers to inject malicious scripts that execute in the context of other users' browsers. The stored XSS aspect emerges when the malicious input is persistently stored on the device and later served to other users, making the attack more persistent and potentially more damaging. The snmpSysName parameter specifically serves as the attack surface because it accepts user-supplied values for system identification purposes, but fails to implement proper security controls to prevent malicious code injection. This vulnerability directly maps to CWE-79, which defines Cross-site Scripting as a weakness where applications fail to properly escape output, allowing attackers to inject client-side scripts into web pages viewed by other users.
The operational impact of this vulnerability extends beyond simple web interface exploitation, as it can enable attackers to compromise the entire network infrastructure. Network administrators who access the device management interface become potential targets for credential theft, session hijacking, or redirection to malicious sites. The stored nature of the vulnerability means that even after the initial attack, the malicious code continues to execute against any user who accesses the device interface, potentially affecting multiple administrators or users over time. Attackers could leverage this vulnerability to establish persistent access points, steal administrative credentials, or redirect users to phishing sites that appear legitimate. The impact is particularly severe given that these are network infrastructure devices that often have elevated privileges and access to sensitive network information, making them attractive targets for attackers seeking to establish footholds within larger network environments.
Mitigation strategies for this vulnerability require immediate attention from network administrators and security teams. The primary recommendation involves updating the firmware to versions that address the XSS vulnerability in the web interface, as ASUS has likely released patches to resolve this specific issue. Additionally, network segmentation and access controls should be implemented to limit access to administrative interfaces to trusted networks only. Input validation should be strengthened at multiple layers, including implementing proper output encoding for all user-supplied parameters and ensuring that SNMP system name fields are properly sanitized before processing. Network monitoring should be enhanced to detect unusual traffic patterns or attempts to exploit known XSS vectors, particularly targeting web interface parameters like snmpSysName. Organizations should also consider implementing web application firewalls to detect and block malicious script injection attempts, and conduct regular security assessments of network infrastructure devices to identify similar vulnerabilities in other equipment. This vulnerability aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, and T1566 for Phishing, as attackers could use the XSS vulnerability to redirect users to malicious sites or steal session information.