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QNAP NAS Hybrid Backup Missing Authentication for Critical Function Remote Code Execution Vulnerability

July 8th, 2021

Vulnerability Details

This vulnerability allows remote attackers to execute arbitrary code on affected installations of QNAP NAS. Authentication is not required to exploit this vulnerability.

The specific flaw exists within the RTSS server, which listens on TCP port 8899 by default. The issue results from the lack of authentication prior to allowing alterations to the system configuration. An attacker can leverage this vulnerability to execute arbitrary code in the context of the Administrator.

Additional Details

QNAP has issued an update to correct this vulnerability. More details can be found at:
https://www.qnap.com/en-us/security-advisory/QSA-21-19

Disclosure Timeline

  • 2021-05-05 - Vulnerability reported to vendor
  • 2021-07-08 - Coordinated public release of advisory

Credit

Ta-Lun Yen of TXOne IoT/ICS Security Research Labs (Trend Micro)

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