CVE-2021-28799
QNAP NAS Improper Authorization Vulnerability - [Actively Exploited]
Description
An improper authorization vulnerability has been reported to affect QNAP NAS running HBS 3 (Hybrid Backup Sync. ) If exploited, the vulnerability allows remote attackers to log in to a device. This issue affects: QNAP Systems Inc. HBS 3 versions prior to v16.0.0415 on QTS 4.5.2; versions prior to v3.0.210412 on QTS 4.3.6; versions prior to v3.0.210411 on QTS 4.3.4; versions prior to v3.0.210411 on QTS 4.3.3; versions prior to v16.0.0419 on QuTS hero h4.5.1; versions prior to v16.0.0419 on QuTScloud c4.5.1~c4.5.4. This issue does not affect: QNAP Systems Inc. HBS 2 . QNAP Systems Inc. HBS 1.3 .
INFO
Published Date :
May 13, 2021, 3:15 a.m.
Last Modified :
March 12, 2025, 8:57 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CISA KEV (Known Exploited Vulnerabilities)
For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.
QNAP NAS running HBS 3 contains an improper authorization vulnerability which can allow remote attackers to log in to a device.
Apply updates per vendor instructions.
https://nvd.nist.gov/vuln/detail/CVE-2021-28799
Affected Products
The following products are affected by CVE-2021-28799
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | CRITICAL | [email protected] | ||||
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Apply the workaround and upgrade to the relevant fixed version referenced in the QSA-21-13 advisory.
Public PoC/Exploit Available at Github
CVE-2021-28799 has a 3 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-28799.
| URL | Resource |
|---|---|
| https://www.qnap.com/en/security-advisory/QSA-21-13 | Vendor Advisory |
| https://www.qnap.com/en/security-advisory/QSA-21-13 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-28799 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-28799
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Resources for Security Matters talk 2022
Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.
cisa-kev vulnerability 0day cisa exploits
主流供应商的一些攻击性漏洞汇总
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-28799 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-28799 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Modified Analysis by [email protected]
Mar. 12, 2025
Action Type Old Value New Value Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415 OR cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415 OR cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:* Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415 OR cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 16.0.0415 OR cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:* Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412 OR cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412 OR cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:* Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412 OR cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210412 OR cpe:2.3:o:qnap:qts:4.3.6:*:*:*:*:*:*:* Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411 OR cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:* cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411 OR cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:* cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:* Changed CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411 OR cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:* cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:* AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions from (excluding) 3.0.210411 OR cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:* cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:* -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Nov. 21, 2024
Action Type Old Value New Value Added Reference https://www.qnap.com/en/security-advisory/QSA-21-13 -
CVE Modified by [email protected]
May. 14, 2024
Action Type Old Value New Value -
Reanalysis by [email protected]
Jul. 14, 2022
Action Type Old Value New Value Removed CWE NIST CWE-863 Added CWE NIST NVD-CWE-Other -
CPE Deprecation Remap by [email protected]
Jun. 21, 2021
Action Type Old Value New Value Changed CPE Configuration OR *cpe:2.3:a:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:* OR *cpe:2.3:o:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:* -
Initial Analysis by [email protected]
Jun. 01, 2021
Action Type Old Value New Value Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:P/A:P) Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Changed Reference Type https://www.qnap.com/en/security-advisory/QSA-21-13 No Types Assigned https://www.qnap.com/en/security-advisory/QSA-21-13 Vendor Advisory Added CWE NIST CWE-863 Added CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0415 OR cpe:2.3:a:qnap:qts:4.5.2:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210412 OR cpe:2.3:a:qnap:qts:4.3.6:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 3.0.210411 OR cpe:2.3:a:qnap:qts:4.3.3:*:*:*:*:*:*:* cpe:2.3:a:qnap:qts:4.3.4:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0419 OR cpe:2.3:a:qnap:quts_hero:h4.5.1:*:*:*:*:*:*:* Added CPE Configuration AND OR *cpe:2.3:a:qnap:hybrid_backup_sync:*:*:*:*:*:*:*:* versions up to (excluding) 16.0.0419 OR cpe:2.3:o:qnap:qutscloud:*:*:*:*:*:*:*:* versions from (including) c4.5.1 up to (including) c4.5.4
Vulnerability Scoring Details
Base CVSS Score: 10
Base CVSS Score: 7.5
Exploit Prediction
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.
88.77 }} -0.02%
score
0.99499
percentile