CVE-2017-8838 in Balance
Summary
by MITRE
XSS via syncid exists on Peplink Balance 305, 380, 580, 710, 1350, and 2500 devices with firmware before fw-b305hw2_380hw6_580hw2_710hw3_1350hw2_2500-7.0.1-build2093. The affected script is cgi-bin/HASync/hasync.cgi.
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Analysis
by VulDB Data Team • 06/25/2024
The vulnerability CVE-2017-8838 represents a cross-site scripting flaw that affects multiple Peplink Balance series devices including models 305, 380, 580, 710, 1350, and 2500. This security weakness exists within the firmware versions prior to fw-b305hw2_380hw6_580hw2_710hw3_1350hw2_2500-7.0.1-build2093 and specifically targets the cgi-bin/HASync/hasync.cgi script. The affected devices operate within network infrastructure environments where they handle synchronization processes between primary and backup systems, making them critical components for maintaining network availability and redundancy. The vulnerability arises from insufficient input validation and sanitization within the synchronization identifier parameter, which allows malicious actors to inject arbitrary script code that executes in the context of other users' browsers. This particular flaw falls under CWE-79 which categorizes cross-site scripting vulnerabilities as a result of improper neutralization of input during web page generation. The attack vector is particularly concerning as it leverages the legitimate synchronization functionality of these network devices, making it difficult for administrators to distinguish between normal operational traffic and malicious payloads.
The technical implementation of this vulnerability occurs when the hasync.cgi script processes the syncid parameter without adequate sanitization of user-supplied input. When a malicious actor submits crafted script code within the syncid parameter, the web application fails to properly escape or filter the input before incorporating it into dynamically generated web content. This allows the malicious code to be executed in the browser context of authenticated users who access the device management interface. The vulnerability is particularly dangerous because it can be exploited by attackers who do not require authentication to the device itself, as the malicious payload can be injected through the synchronization process that typically occurs between primary and backup systems. The operational impact extends beyond simple script execution as this vulnerability could enable attackers to perform session hijacking, steal administrative credentials, or manipulate network configurations through the device's management interface. Network administrators who rely on these devices for critical infrastructure protection face significant risk as this vulnerability could allow unauthorized access to network traffic management and configuration settings.
The exploitation of CVE-2017-8838 aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to initial access and privilege escalation. Attackers can leverage this vulnerability as part of a broader attack chain to gain persistent access to network infrastructure, potentially using the compromised device as a foothold for further network exploration. The vulnerability's impact is exacerbated by the fact that these Peplink devices are commonly deployed in enterprise environments where they serve as critical network components for load balancing, failover management, and traffic optimization. Organizations using affected firmware versions face potential data exfiltration risks, as the malicious scripts could capture sensitive information transmitted through the device's management interface. The attack surface is further expanded because these devices often operate in environments where they are directly accessible from internal networks or even exposed to external networks, increasing the likelihood of exploitation. Security professionals should consider this vulnerability as part of their comprehensive network security assessment, particularly when evaluating the security posture of network infrastructure devices that handle synchronization and failover processes.
Organizations should immediately implement mitigation strategies including firmware updates to the patched versions that address the input validation issues within the hasync.cgi script. The most effective immediate solution involves updating all affected Peplink Balance devices to firmware version 7.0.1-build2093 or later, which includes proper input sanitization and validation mechanisms for the syncid parameter. Network segmentation and access control measures should be implemented to limit direct access to these devices from untrusted networks, reducing the attack surface for potential exploitation attempts. Additionally, implementing web application firewalls or security monitoring solutions that can detect and block malicious script injection attempts in the cgi-bin/HASync/hasync.cgi endpoint will provide additional layers of protection. Regular security audits and vulnerability assessments should be conducted to identify any other potentially affected components within the network infrastructure that might be vulnerable to similar cross-site scripting attacks. The remediation process should also include comprehensive network monitoring to detect any anomalous behavior that might indicate exploitation attempts, as the malicious scripts could be used to establish persistent backdoors or exfiltrate sensitive configuration data from the affected devices.