CVE-2018-8917 in DiskStation Manager
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in info.cgi in Synology DiskStation Manager (DSM) before 6.1.6-15266 allows remote attackers to inject arbitrary web script or HTML via the host parameter.
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Analysis
by VulDB Data Team • 01/15/2025
The CVE-2018-8917 vulnerability represents a critical cross-site scripting flaw within Synology DiskStation Manager's info.cgi component, affecting versions prior to 6.1.6-15266. This vulnerability resides in the web application's handling of user input through the host parameter, creating a pathway for remote attackers to execute malicious scripts within the context of other users' browsers. The flaw specifically impacts the DSM web interface, which serves as the primary management console for Synology network-attached storage devices, making it a significant concern for enterprise and home users alike. The vulnerability's classification as a persistent XSS issue means that malicious scripts injected through this vector can remain active and potentially affect multiple users who interact with the compromised system.
The technical implementation of this vulnerability stems from inadequate input validation and output sanitization within the info.cgi script. When the host parameter is processed without proper sanitization, malicious payloads can be embedded directly into the web response, which is then executed by unsuspecting users' browsers. This type of vulnerability falls under CWE-79, which specifically addresses Cross-Site Scripting flaws in web applications. The attack vector requires minimal privileges as remote exploitation is possible without authentication, making it particularly dangerous in environments where the DSM interface is exposed to untrusted networks. The vulnerability's impact is amplified by the fact that DSM administrators often use the web interface from various locations, potentially including public networks or shared computing environments where session hijacking or persistent script execution could occur.
The operational implications of CVE-2018-8917 extend beyond simple script injection, as it enables attackers to perform a wide range of malicious activities within the compromised environment. Attackers could leverage this vulnerability to steal session cookies, redirect users to malicious sites, deface web pages, or even establish persistent backdoors through more sophisticated attack chains. The vulnerability's presence in the DSM's core web components means that successful exploitation could provide attackers with access to sensitive system information, potentially leading to further privilege escalation or lateral movement within networked environments. According to ATT&CK framework, this vulnerability maps to T1059.007 for Command and Scripting Interpreter and T1566.001 for Phishing, as attackers could use the XSS to deliver malicious payloads or manipulate user interactions. The impact is particularly severe for organizations using DSM for critical data storage and management, as the compromise could lead to unauthorized access to sensitive corporate data or disruption of business operations.
Organizations affected by this vulnerability should immediately implement the remediation measures provided by Synology, including updating to DSM version 6.1.6-15266 or later, which contains the necessary patches to address the input validation issues. Network segmentation strategies should be employed to limit exposure of the DSM web interface to trusted networks only, while implementing web application firewalls to detect and block malicious payloads. Regular security audits should include verification of input sanitization practices across all web applications, with particular attention to parameters that are processed without proper validation. The vulnerability demonstrates the importance of maintaining up-to-date firmware and security patches, as well as implementing defense-in-depth strategies that include monitoring for suspicious web traffic patterns and user behavior anomalies. Additionally, administrators should consider implementing content security policies to mitigate the impact of potential XSS attacks, even when primary defenses are bypassed. Security awareness training for system administrators should emphasize the critical nature of patch management and the potential consequences of unpatched vulnerabilities in network infrastructure components.