CVE-2015-4655 in DiskStation Manager
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Synology DiskStation Manager (DSM) before 5.2-5565 Update 1 allows remote attackers to inject arbitrary web script or HTML via the "compound" parameter to entry.cgi.
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Analysis
by VulDB Data Team • 01/15/2025
The vulnerability identified as CVE-2015-4655 represents a critical cross-site scripting flaw within Synology DiskStation Manager (DSM) software affecting versions prior to 5.2-5565 Update 1. This weakness resides in the web interface handling of user-supplied input through the "compound" parameter within the entry.cgi script, creating a persistent vector for malicious code injection. The vulnerability operates at the application layer and specifically targets the web server component of the DSM platform, which serves as the primary interface for system administration and file management operations. The flaw enables attackers to execute arbitrary web scripts or HTML code within the context of other users' browsers, potentially compromising the security of the entire network storage environment. This type of vulnerability falls under CWE-79, which specifically addresses cross-site scripting conditions where input data is not properly validated or sanitized before being rendered in web pages.
The operational impact of this vulnerability extends beyond simple script injection, as it allows remote attackers to manipulate the DSM web interface and potentially gain unauthorized access to sensitive system information. When a user visits a maliciously crafted URL containing the XSS payload, the script executes within their browser session, potentially stealing authentication cookies, redirecting users to malicious sites, or performing unauthorized administrative actions on behalf of the victim. The attack requires no special privileges or authentication to exploit, making it particularly dangerous in environments where multiple users access the DSM interface. The vulnerability affects the core authentication and authorization mechanisms of the system, potentially enabling attackers to escalate privileges or access restricted administrative functions.
The exploitation of this vulnerability demonstrates the importance of input validation and output encoding practices in web applications, aligning with ATT&CK technique T1059.007 for command and scripting interpreter and T1566.001 for spearphishing attachments. Security professionals should note that this vulnerability represents a classic example of insufficient sanitization of user inputs, where the "compound" parameter in entry.cgi fails to properly validate or escape special characters that could be interpreted as HTML or JavaScript code. The affected DSM versions likely lacked proper contextual output encoding mechanisms that would prevent malicious code from executing when rendered in web browsers. This vulnerability type is particularly concerning in enterprise environments where DSM serves as the primary storage management interface, as it could enable attackers to compromise entire network storage infrastructures through a single vulnerable parameter.
Mitigation strategies for CVE-2015-4655 involve immediate deployment of Synology DSM Update 5.2-5565 or later versions that address the XSS vulnerability through proper input validation and output sanitization measures. Organizations should implement comprehensive web application firewall rules to filter malicious payloads targeting the entry.cgi endpoint and establish regular patch management processes to ensure all DSM components remain current with security updates. Network segmentation and access control measures should be implemented to limit exposure of the DSM interface to trusted networks only, while user education regarding suspicious links and phishing attempts should be reinforced. Additionally, security monitoring should include detection of anomalous web traffic patterns that may indicate exploitation attempts, and regular security assessments should verify proper implementation of input validation controls across all web applications within the organization's infrastructure. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies to protect against persistent threats targeting web-based administrative interfaces.