OS Command InjectionWeakness · CWE-78

CVE-2024-3721

MEDIUM · 6.3 CVSS v3.1 Published 2024-04-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
69/100
Remediation priority · Elevated
High EPSS Remotely reachable Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A vulnerability was found in TBK DVR-4104 and DVR-4216 up to 20240412 and classified as critical. This issue affects some unknown processing of the file /device.rsp?opt=sys&cmd=___S_O_S_T_R_E_A_MAX___. The manipulation of the argument mdb/mdc leads to os command injection. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-260573 was assigned to this vulnerability.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

OS command injection vulnerability in TBK DVR-4104 and DVR-4216 digital video recorders. The /device.rsp endpoint fails to sanitize the mdb/mdc parameter before passing it to system commands, allowing remote attackers to execute arbitrary OS commands via crafted requests to the sys command handler.

MitigationRestrict network exposure of the DVR management interface via firewall or VLAN isolation immediately, as a public exploit exists. Contact TBK for firmware updates; if unavailable, evaluate replacement with a currently supported device.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device model
    Access the DVR web interface or check physical device labeling for model number TBK DVR-4104 or DVR-4216
    Affected if Device is a TBK DVR-4104 or DVR-4216 model
  2. Check firmware version
    Log into the DVR admin interface and navigate to System > Information, or send an HTTP request to the device to retrieve the firmware version string
    Affected if Firmware version is unknown, unpatched, or falls within any known affected version range provided by TBK
  3. Verify web interface accessibility
    Attempt to access http://[DVR-IP]/device.rsp from a browser or curl command to confirm the /device.rsp endpoint is reachable
    Affected if The /device.rsp endpoint responds and is accessible over the network
  4. Confirm vulnerable parameter exists
    Send a benign test request to /device.rsp with the sys command handler and observe if the mdb or mdc parameters are accepted (note: do not inject actual commands)
    Affected if The endpoint accepts sys command handler requests with mdb/mdc parameters without requiring authentication or validation errors
  5. Check network exposure
    Review firewall rules, NAT configurations, or VLAN settings to determine if the DVR management web interface is accessible from untrusted networks or the internet
    Affected if The DVR web interface is directly exposed to the internet or untrusted internal networks

The environment is affected if it contains a TBK DVR-4104 or DVR-4216 with an unpatched firmware version and the /device.rsp endpoint with sys command handler is accessible over the network.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Restrict network exposure of the DVR management interface via firewall or VLAN isolation immediately, as a public exploit exists. Contact TBK for firmware updates; if unavailable, evaluate replacement with a currently supported device.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation10.0 h
  • Testing5.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,510
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2024-3721 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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