CVE-2021-28809: QNAP NAS Hybrid Backup Missing Authentication for Critical Function Remote Code Execution Vulnerability
An improper access control vulnerability has been reported to affect certain legacy versions of HBS 3. If exploited, this vulnerability allows attackers to compromise the security of the operating system.QNAP have already fixed this vulnerability in the following versions of HBS 3: QTS 4.3.6: HBS 3 v3.0.210507 and later QTS 4.3.4: HBS 3 v3.0.210506 and later QTS 4.3.3: HBS 3 v3.0.210506 and later
Other sources
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.
Affected Software
Remediation
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Event History
Frequently Asked Questions
What is CVE-2021-28809?
CVE-2021-28809 is a vulnerability that allows remote attackers to execute arbitrary code on affected installations of QNAP NAS.
How severe is CVE-2021-28809?
CVE-2021-28809 has a severity score of 9.8, which is classified as critical.
What is the affected software for CVE-2021-28809?
The affected software for CVE-2021-28809 includes QNAP NAS with Hybrid Backup Sync up to version 3.0.210507.
Is QNAP QTS vulnerable to CVE-2021-28809?
No, QNAP QTS versions 4.3.6, 4.3.4, and 4.3.3 are not vulnerable to CVE-2021-28809.
How can I fix CVE-2021-28809?
To fix CVE-2021-28809, users should update their QNAP NAS Hybrid Backup Sync to version 3.0.210507 or later.