CVE-2020-3923Network attack vector

Unauthorized access via crackable default password

Published Feb 27, 2020 · Updated Sep 16, 2024

Broken access control in TONNET DVR firmware before 20191216 (TAT-76) and 20200213 (TAT-77) allows remote attackers to gain system access. The firmware uses a misconfigured authentication mechanism that exposes a default password which attackers can crack. Network access without prior privileges is sufficient, and successful access can compromise confidentiality, integrity, and availability of the DVR.

CVSS severity9.8
Critical
EPSS probability1.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Broken access control in TONNET DVR firmware before 20191216 (TAT-76) and 20200213 (TAT-77) allows remote attackers to gain system access. The firmware uses a misconfigured authentication mechanism that exposes a default password which attackers can crack. Network access without prior privileges is sufficient, and successful access can compromise confidentiality, integrity, and availability of the DVR.

The record

CVE
CVE-2020-3923
Published
Feb 27, 2020
Updated
Sep 16, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1110.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 27, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
8.1TWCERT/CCCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1110.002Password Cracking

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo