CVE-2025-52867
📋 TL;DR
An uncontrolled resource consumption vulnerability in Qsync Central allows authenticated remote attackers to cause denial-of-service conditions. This affects all QNAP Qsync Central installations before version 5.0.0.2. Attackers need valid user credentials to exploit this vulnerability.
💻 Affected Systems
- QNAP Qsync Central
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service unavailability for Qsync Central, disrupting file synchronization services across the organization.
Likely Case
Degraded performance or temporary service interruptions affecting file synchronization capabilities.
If Mitigated
Minimal impact with proper access controls and monitoring in place.
🎯 Exploit Status
Exploitation requires valid user credentials. The vulnerability allows resource exhaustion attacks once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Qsync Central 5.0.0.2 (2025/07/31) and later
Vendor Advisory: https://www.qnap.com/en/security-advisory/qsa-25-35
Restart Required: Yes
Instructions:
1. Log into QNAP App Center. 2. Check for updates to Qsync Central. 3. Install version 5.0.0.2 or later. 4. Restart Qsync Central service or the entire NAS if required.
🔧 Temporary Workarounds
Restrict User Access
allLimit Qsync Central access to only necessary users and implement strong authentication controls.
Network Segmentation
allPlace Qsync Central behind network segmentation and restrict access to trusted IP addresses only.
🧯 If You Can't Patch
- Implement strict access controls and monitor for unusual resource consumption patterns.
- Consider temporarily disabling Qsync Central for non-critical users until patching is possible.
🔍 How to Verify
Check if Vulnerable:
Check Qsync Central version in QNAP App Center. If version is below 5.0.0.2, the system is vulnerable.Check Version:
Check via QNAP web interface: App Center → Installed Apps → Qsync CentralVerify Fix Applied:
Verify Qsync Central version shows 5.0.0.2 or later in App Center and monitor for normal resource usage.📡 Detection & Monitoring
Log Indicators:
- Unusual resource consumption spikes in system logs
- Multiple authentication attempts followed by high resource usage
Network Indicators:
- Abnormal traffic patterns to Qsync Central service ports
- Repeated connections from single sources
SIEM Query:
source="qnap_logs" AND (resource_usage>threshold OR "Qsync Central" AND error)