CVE-2017-5157 in homeLYnk
Summary
by MITRE
An issue was discovered in Schneider Electric homeLYnk Controller, LSS100100, all versions prior to V1.5.0. The homeLYnk controller is susceptible to a cross-site scripting attack. User inputs can be manipulated to cause execution of JavaScript code.
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Analysis
by VulDB Data Team • 08/14/2020
The vulnerability identified as CVE-2017-5157 affects Schneider Electric's homeLYnk Controller model LSS100100 across all firmware versions prior to V1.5.0, representing a critical security flaw that undermines the integrity of the device's web interface. This cross-site scripting vulnerability arises from inadequate input validation mechanisms within the controller's user interface, allowing malicious actors to inject and execute arbitrary JavaScript code through crafted user inputs. The flaw specifically manifests when the device processes web requests containing malicious payloads, creating an attack surface that can be exploited by remote threat actors without requiring physical access to the device. The homeLYnk Controller serves as a central hub for home automation systems, making this vulnerability particularly concerning as it could potentially compromise the entire connected home ecosystem. The vulnerability directly maps to CWE-79, which defines Cross-Site Scripting as a weakness where untrusted data is incorporated into web pages without proper validation or sanitization, enabling attackers to execute malicious scripts in the context of the victim's browser. The attack vector leverages the device's web-based management interface, which is commonly accessible over the internet for remote configuration and monitoring purposes.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied data within the controller's web application framework, where input parameters are directly reflected in HTTP responses without appropriate encoding or validation measures. When legitimate users interact with the device's interface, malicious payloads can be injected through form fields, URL parameters, or other input mechanisms, leading to script execution in the context of the authenticated user's session. This allows attackers to perform actions such as stealing session cookies, redirecting users to malicious websites, or even modifying device configurations through the execution of malicious JavaScript code. The vulnerability is particularly dangerous because it can be exploited remotely, meaning attackers do not require physical access to the device or network proximity to carry out successful attacks. The lack of proper input validation creates a persistent threat that remains active until the firmware is updated to V1.5.0 or later versions that include appropriate sanitization measures. The device's role in home automation systems means that successful exploitation could potentially lead to broader security implications, including unauthorized access to other connected devices within the home network.
The operational impact of CVE-2017-5157 extends beyond simple script execution, as it represents a fundamental breach of the device's security model that could enable more sophisticated attacks within the home network environment. Attackers leveraging this vulnerability could potentially establish persistent access points, monitor network traffic, or manipulate automation sequences that control lighting, security systems, and other connected devices. The exploitation of this vulnerability aligns with ATT&CK technique T1059.007, which covers Scripting through the execution of JavaScript code, and could potentially lead to privilege escalation or lateral movement within the compromised network. Organizations and homeowners using affected devices face significant risks including unauthorized access to personal data, potential disruption of home automation services, and the possibility of using the compromised device as a launching point for attacks against other networked devices. The vulnerability's classification under the broader category of web application security flaws means that it could be exploited in conjunction with other attack vectors to create more comprehensive compromise scenarios. The long-term implications include potential data exfiltration, device hijacking, and the establishment of persistent backdoors that could remain undetected for extended periods.
Mitigation strategies for CVE-2017-5157 primarily focus on firmware updates to version V1.5.0 or later, which include proper input validation and sanitization mechanisms that prevent malicious payloads from being executed. Network administrators should implement additional protective measures including network segmentation to isolate affected devices from critical systems, deployment of web application firewalls to monitor and filter traffic, and regular security assessments to identify potential exploitation attempts. The implementation of secure coding practices and input validation should be enforced in all web applications, particularly those managing critical infrastructure or personal data. Organizations should also consider implementing network monitoring solutions that can detect anomalous traffic patterns indicative of exploitation attempts. Regular vulnerability scanning and penetration testing of home automation systems can help identify similar weaknesses in other connected devices that may be vulnerable to the same class of attack. The remediation process should include comprehensive testing of updated firmware to ensure that security patches do not introduce compatibility issues with existing home automation configurations. Additionally, users should be educated about the importance of keeping firmware updated and the risks associated with exposing home automation devices to unsecured network environments. The vulnerability serves as a reminder of the critical importance of secure software development practices in IoT devices and the need for robust input validation mechanisms in all web-facing applications.