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Eibport FirmwareOperating system · Bab Technologie

CVE-2021-28913

CRITICAL · 9.8 CVSS v3.1 Published 2021-09-09
Fix available
A fix is available. Upgrade to 3.9.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges 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
BAB TECHNOLOGIE GmbH eibPort V3 prior version 3.9.1 allow unauthenticated attackers access to /webif/SecurityModule to validate the so called and hard coded unique 'eibPort String' which acts as the root SSH key passphrase. This is usable and part of an attack chain to gain SSH root access.

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

The eibPort V3 web interface contains an unauthenticated access vulnerability in /webif/SecurityModule that allows attackers to validate a hardcoded unique 'eibPort String'. This string functions as the root SSH key passphrase, enabling remote attackers to gain SSH root access to the device as part of an attack chain.

MitigationUpgrade eibPort V3 to version 3.9.1 or later to obtain the patched firmware, and immediately rotate any exposed or hardcoded credentials including the eibPort String and SSH keys.

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

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Eibport FirmwareOperating system
Affected:< 3.9.1

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 eibPort V3 web interface availability
    Attempt to access the base web interface of the device (typically on ports 80 or 443) and confirm it is a Bab Technologie eibPort V3 system.
    Affected if The web interface responds and identifies itself as an eibPort V3 device.
  2. Check for vulnerable SecurityModule endpoint
    Access the path /webif/SecurityModule on the web server (e.g., http://[device-ip]/webif/SecurityModule) and observe whether the endpoint exists and responds.
    Affected if The /webif/SecurityModule endpoint returns a valid response (200 OK), indicating the vulnerable code is present.
  3. Determine installed firmware version
    Locate the firmware version information either in the web interface (typically under System > Info or similar), via SSH access if already obtained, or through SNMP enumeration. Compare the version against the affected range.
    Affected if The installed firmware version is below 3.9.1 (e.g., 3.9.0, 3.8.x, or earlier).
  4. Verify SSH service accessibility
    Attempt to connect to the device on port 22 (or configured SSH port) using an SSH client. Determine if root login is permitted or if the SSH service is exposed to the network.
    Affected if SSH service is accessible on the device and accepts authentication attempts, making it potentially vulnerable to the hardcoded passphrase attack.

A user is affected if they run an eibPort V3 firmware version below 3.9.1 with the web interface and SSH service exposed, where the /webif/SecurityModule endpoint is accessible.

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.

dbcve · scoped
Upgrade available Upgrade to 3.9.1 or later
Fixed in 3.9.1
Interim mitigation

Upgrade eibPort V3 to version 3.9.1 or later to obtain the patched firmware, and immediately rotate any exposed or hardcoded credentials including the eibPort String and SSH keys.

Recommended fix High confidence

3.9.1

  1. Obtain the official eibPort V3 firmware version 3.9.1 or later from BAB TECHNOLOGIE GmbH's official distribution channels
  2. Access the eibPort device administration interface
  3. Navigate to the firmware update or system maintenance section
  4. Upload and apply the firmware version 3.9.1
  5. Verify the upgrade was successful by confirming the new version in the system information
  6. Restart the device if required by the upgrade process
  7. Verify that the /webif/SecurityModule endpoint now requires authentication

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Eibport Firmware Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

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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-2021-28913 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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