CVE-2017-7631 in QTS
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the share link function of File Station of QNAP 4.2.6 build 20171026, QTS 4.3.3 build 20170727 and earlier allows remote attackers to inject arbitrary web script or HTML.
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Analysis
by VulDB Data Team • 01/17/2020
The vulnerability identified as CVE-2017-7631 represents a critical cross-site scripting flaw within the File Station component of QNAP NAS devices running specific firmware versions. This vulnerability exists in the share link functionality that enables users to generate and distribute links for shared files and folders. The flaw allows remote attackers to inject malicious web scripts or HTML code through the share link generation process, potentially compromising the security of users who access these links.
The technical implementation of this vulnerability stems from inadequate input validation and output encoding within the File Station's share link function. When users create share links for files or directories, the system fails to properly sanitize user-supplied input parameters that are subsequently rendered in the generated HTML output. This failure creates an opening for attackers to inject malicious payloads that execute in the context of other users' browsers when they access the compromised share links. The vulnerability specifically affects QNAP firmware versions including QNAP 4.2.6 build 20171026 and QTS 4.3.3 build 20170727, along with earlier versions of these operating systems.
The operational impact of this vulnerability extends beyond simple script injection, potentially enabling attackers to perform session hijacking, steal user credentials, redirect victims to malicious websites, or execute arbitrary commands within the context of the victim's browser session. Given that QNAP devices are commonly used in both personal and enterprise environments, the exploitation of this vulnerability could lead to unauthorized access to sensitive data, compromise of user accounts, and potential lateral movement within network infrastructures. The remote nature of the attack means that threat actors do not require physical access to the device or network presence to exploit this vulnerability, making it particularly dangerous for organizations relying on QNAP NAS solutions for file sharing and storage.
Security professionals should note that this vulnerability aligns with CWE-79, which describes cross-site scripting flaws, and represents a classic example of insufficient output encoding in web applications. From an ATT&CK framework perspective, this vulnerability could be leveraged for initial access through malicious link delivery, credential theft via session hijacking, and privilege escalation by compromising user sessions. Organizations should implement immediate mitigations including firmware updates to patched versions, network monitoring for suspicious share link creation activities, and user education regarding the dangers of clicking untrusted links. Additionally, implementing Content Security Policies and input validation measures can provide additional defense-in-depth layers to protect against similar vulnerabilities in the future.