CVE-2018-19942 in QTS
Summary
by MITRE • 04/16/2021
A cross-site scripting (XSS) vulnerability has been reported to affect earlier versions of File Station. If exploited, this vulnerability allows remote attackers to inject malicious code. We have already fixed this vulnerability in the following versions: QTS 4.5.2.1566 build 20210202 (and later) QTS 4.5.1.1456 build 20201015 (and later) QTS 4.3.6.1446 build 20200929 (and later) QTS 4.3.4.1463 build 20201006 (and later) QTS 4.3.3.1432 build 20201006 (and later) QTS 4.2.6 build 20210327 (and later) QuTS hero h4.5.1.1472 build 20201031 (and later) QuTScloud c4.5.4.1601 build 20210309 (and later) QuTScloud c4.5.3.1454 build 20201013 (and later)
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Analysis
by VulDB Data Team • 04/21/2021
The vulnerability identified as CVE-2018-19942 represents a critical cross-site scripting flaw within Synology's File Station component that affects multiple versions of the QTS operating system and related products. This vulnerability resides in the web interface handling of user input parameters, specifically within the file management functionality that processes user-provided data without adequate sanitization or validation mechanisms. The flaw enables remote attackers to inject malicious scripts into web pages viewed by other users, creating a persistent threat vector that can compromise user sessions and potentially lead to unauthorized access to sensitive data stored within the file system.
The technical implementation of this vulnerability stems from insufficient input validation and output encoding practices within the File Station's web application layer. When users interact with file management features, particularly when handling file names, paths, or metadata, the application fails to properly sanitize user-supplied data before rendering it in web responses. This creates an environment where attacker-controlled input can be executed as client-side scripts within the context of other users' browser sessions, directly violating the fundamental security principle of input validation and output encoding. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws in web applications, and follows the ATT&CK technique T1059.007 for script injection attacks targeting web applications.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with the capability to perform session hijacking, steal user credentials, and potentially escalate privileges within the file system. An attacker could craft malicious file names or metadata that, when viewed by other users, would execute malicious JavaScript code in their browsers. This could lead to unauthorized access to shared files, modification of file contents, or even complete system compromise if the attacker can leverage the vulnerability to escalate privileges. The attack surface is particularly concerning given that File Station serves as a core component for file management and sharing within Synology's ecosystem, making it a prime target for adversaries seeking persistent access to networked storage systems.
Organizations utilizing affected versions of Synology's QTS operating system and related products must prioritize immediate remediation through the recommended firmware updates provided in the advisory. The patched versions listed in the advisory demonstrate Synology's response to address the vulnerability through proper input validation mechanisms and enhanced output encoding practices. Security administrators should conduct comprehensive vulnerability assessments across their entire network infrastructure to identify any systems running unsupported versions of the affected software. The mitigation strategy should include not only applying the recommended firmware updates but also implementing network monitoring to detect potential exploitation attempts and establishing incident response procedures for potential compromise scenarios. Organizations should also consider implementing additional security controls such as web application firewalls and regular security audits to prevent similar vulnerabilities from emerging in other components of their network infrastructure.