CVE-2020-25234
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 · uneditedA vulnerability has been identified in LOGO! 8 BM (incl. SIPLUS variants) (All versions < V8.3), LOGO! Soft Comfort (All versions < V8.3). The LOGO! program files generated and used by the affected components offer the possibility to save user-defined functions (UDF) in a password protected way. This protection is implemented in the software that displays the information. An attacker could reverse engineer the UDFs directly from stored program files.
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 confidenceThe vulnerability stems from weak protection of User Defined Functions (UDFs) in Siemens LOGO! 8 BM and LOGO! Soft Comfort. Password protection is implemented only at the UI/display software level rather than cryptographically in the file format itself, allowing attackers to reverse engineer UDFs directly from stored program files by parsing the unprotected data structures.
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< 8.3CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/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 checksWork through these to decide whether this CVE applies to you.
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Check LOGO! 8 BM firmware versionAccess the LOGO! 8 BM device display or web interface and navigate to the device information or system settings to view the installed firmware version.Affected if The displayed firmware version is less than 8.3 (for example, 8.2.x or earlier)
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Identify program files from LOGO! Soft ComfortLocate any program files created with LOGO! Soft Comfort on your system or network storage. These are typically stored with a specific project file extension used by the software.Affected if You have program files that were created with versions of LOGO! Soft Comfort prior to the V8.3 update
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Inspect UDF presence in program filesOpen the program file in a hex editor or binary inspection tool and look for recognizable patterns or structures that may indicate User Defined Functions are embedded within the file.Affected if The program file contains UDF data structures that can be parsed without decryption
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Verify file format protectionAttempt to read and parse the program file directly using third-party tools or scripts, observing whether UDF content is accessible without needing to authenticate or decrypt.Affected if UDF code or logic can be extracted by directly parsing the file without requiring cryptographic keys or authenticated access
You are affected if your LOGO! 8 BM firmware is below version 8.3 AND you have program files containing UDFs that were created with earlier software versions, as the file format lacks cryptographic protection.
Generated from the published advisory. Verify against your own configuration.
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 data8.3
Upgrade to LOGO! version V8.3 or later which addresses the weak protection mechanism. Additionally, restrict access to program files and treat them as sensitive intellectual property.
- Consultation2.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-25234 — 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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-25234 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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