Logo\! 8 Bm FirmwareOperating system · Siemens

CVE-2020-25229

HIGH · 7.5 CVSS v3.1 Published 2020-12-14
Fix available
A fix is available. Upgrade to 8.3 or later.
See remediation →
84/100
Remediation priority · High
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
A vulnerability has been identified in LOGO! 8 BM (incl. SIPLUS variants) (All versions < V8.3). The implemented encryption for communication with affected devices is prone to replay attacks due to the usage of a static key. An attacker could change the password or change the configuration on any affected device if using prepared messages that were generated for another device.

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 LOGO! 8 BM devices use a static encryption key for device communication, allowing attackers to capture valid encrypted messages from one device and replay them to other affected devices. This replay attack enables unauthorized password changes or configuration modifications on any vulnerable device.

MitigationUpgrade all LOGO! 8 BM devices to firmware version V8.3 or later, which implements proper dynamic key generation. Until patches are applied, isolate affected devices on restricted network segments and monitor for suspicious repeated authentication patterns.

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
Logo\! 8 Bm FirmwareOperating system
Affected:< 8.3

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
None
Integrity
High
Availability
None

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

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
    Locate the physical device or check network inventory to confirm the device is a Siemens LOGO! 8 BM (BM = Base Module). Verify the model number on the device label or in your asset inventory.
    Affected if The device is any Siemens LOGO! 8 BM variant (not newer Logo! 8.3 or 8.4 models)
  2. Determine the installed firmware version
    Access the device through Logo! Soft Comfort software, or log into the device web interface if available, or check the device system info via the display menu. Note the firmware version displayed.
    Affected if The firmware version cannot be determined or is visible as a version number lower than 8.3
  3. Compare version against affected range
    Check the firmware version number against the affected range: any version before 8.3 (for example, 8.2, 8.1, 8.0, or earlier) indicates the device uses the static encryption key vulnerable to replay attacks.
    Affected if The firmware version is below 8.3 (for example, 8.2.x or earlier)
  4. Confirm static key vulnerability context
    Understand that this is a design-level flaw in firmware versions prior to 8.3. The vulnerability exists because all devices shipped with firmware below 8.3 share the same static encryption key for device communication.
    Affected if The device is running any pre-V8.3 firmware regardless of configuration settings

If the device is a Siemens LOGO! 8 BM and the firmware version is below 8.3, the device is affected by this vulnerability and could be impacted by replay attacks using captured encrypted messages.

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
Upgrade available Upgrade to 8.3 or later
Fixed in 8.3
Interim mitigation

Upgrade all LOGO! 8 BM devices to firmware version V8.3 or later, which implements proper dynamic key generation. Until patches are applied, isolate affected devices on restricted network segments and monitor for suspicious repeated authentication patterns.

Fix this in Logo\! 8 Bm Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation20.0 h
  • Testing10.0 h
  • Review / QA6.0 h
48.0 hours of engineering $8,580
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2020-25229 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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-2020-25229 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data