CVE-2025-53595 Overview
CVE-2025-53595 is a SQL injection vulnerability [CWE-89] in QNAP Qsync Central, a centralized file synchronization service for QNAP NAS devices. An authenticated remote attacker with a valid user account can inject malicious SQL statements to execute unauthorized code or commands on the affected system. QNAP addressed the issue in Qsync Central version 5.0.0.2, released on 2025/07/31. The flaw affects confidentiality and integrity of stored data and may enable lateral movement within the storage environment.
Critical Impact
Authenticated remote attackers can execute unauthorized code or commands through SQL injection, compromising data confidentiality and integrity on affected QNAP NAS deployments.
Affected Products
- QNAP Qsync Central versions prior to 5.0.0.2
- QNAP NAS devices running vulnerable Qsync Central installations
- Enterprise file synchronization environments built on QNAP storage
Discovery Timeline
- 2025-10-03 - CVE-2025-53595 published to NVD
- 2025-10-08 - Last updated in NVD database
- 2025-07-31 - QNAP releases fixed version Qsync Central 5.0.0.2
Technical Details for CVE-2025-53595
Vulnerability Analysis
The vulnerability is classified as Improper Neutralization of Special Elements used in an SQL Command [CWE-89]. Qsync Central fails to properly sanitize user-supplied input before incorporating it into SQL queries. An attacker with a valid user account can submit crafted parameters that alter the structure and intent of backend database queries.
Successful exploitation allows attackers to read, modify, or extract sensitive database content. According to the QNAP advisory, exploitation can also lead to execution of unauthorized code or commands on the affected system. The vulnerability requires network access and low-privilege authentication, but no user interaction.
Root Cause
The root cause is the absence of proper input validation and parameterized query usage within Qsync Central database operations. User-controlled input flows directly into SQL statement construction, allowing attacker-controlled SQL syntax to be interpreted by the database engine. Qsync Central versions earlier than 5.0.0.2 do not enforce sufficient query parameterization controls.
Attack Vector
The attack vector is network-based and requires authentication with any valid Qsync Central user account. An attacker submits crafted HTTP requests containing malicious SQL payloads through vulnerable parameters in the Qsync Central web interface or API endpoints. Because Qsync Central manages file synchronization for QNAP NAS devices, compromised credentials of even low-privileged users provide a viable foothold. Refer to the QNAP Security Advisory QSA-25-35 for vendor technical details.
Detection Methods for CVE-2025-53595
Indicators of Compromise
- Unusual database query patterns in Qsync Central logs containing SQL meta-characters such as ', --, UNION, or SELECT
- Unexpected outbound connections or command execution originating from the Qsync Central service account
- Anomalous file synchronization activity, including unauthorized access to project shares or user directories
- Unexplained creation, modification, or deletion of database records associated with Qsync Central
Detection Strategies
- Inspect Qsync Central HTTP request logs for parameters containing SQL syntax tokens and boolean injection patterns
- Correlate authenticated user sessions with unusual administrative actions or query volume spikes
- Deploy web application firewall rules that flag SQL injection signatures targeting Qsync Central endpoints
- Baseline normal Qsync Central database query behavior and alert on deviations
Monitoring Recommendations
- Forward QNAP NAS system logs and Qsync Central audit logs to a centralized SIEM for correlation
- Monitor authentication events for brute-force attempts and use of compromised low-privilege accounts
- Track process execution on the NAS host for unexpected child processes spawned by the Qsync Central service
- Alert on configuration or schema changes within the Qsync Central database
How to Mitigate CVE-2025-53595
Immediate Actions Required
- Upgrade Qsync Central to version 5.0.0.2 (released 2025/07/31) or later on all affected QNAP NAS devices
- Audit existing Qsync Central user accounts and remove inactive or unnecessary credentials
- Reset passwords for all Qsync Central users and enforce strong password policies with multi-factor authentication where supported
- Review recent Qsync Central activity logs for signs of prior exploitation
Patch Information
QNAP fixed CVE-2025-53595 in Qsync Central version 5.0.0.2, published on 2025/07/31. Administrators should apply the update through the QNAP App Center or download the package directly from QNAP. Full remediation details are available in the QNAP Security Advisory QSA-25-35.
Workarounds
- Restrict network access to Qsync Central management interfaces using firewall rules or VPN-only access
- Disable Qsync Central temporarily on internet-exposed NAS devices until the patch is applied
- Limit account creation and enforce least-privilege role assignments within Qsync Central
- Place QNAP NAS appliances behind a reverse proxy that performs SQL injection filtering
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
