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Modicon M221 FirmwareOperating system · Schneider Electric

CVE-2018-7792

HIGH · 7.5 CVSS v3.1 Published 2018-08-29
Fix available
A fix is available. Upgrade to 1.6.2.0 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 Permissions, Privileges, and Access Control vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.6.2.0). The vulnerability allows unauthorized users to decode the password using rainbow table.

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 Modicon M221 PLC stores passwords in a weak manner that allows rainbow table attacks, enabling unauthorized users to decode stored passwords. This indicates the password storage uses either unsalted hashes or reversible encoding, making offline password cracking trivial.

MitigationUpdate Modicon M221 firmware to V1.6.2.0 or later, which implements secure password storage. After updating, enforce strong password policies for all user accounts.

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
Modicon M221 FirmwareOperating system
Affected:< 1.6.2.0

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
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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. Confirm Modicon M221 PLC model
    Access the PLC via EcoStruxure Machine Expert (formerly SoMachine) programming software, or physically inspect the device labeling for the Modicon M221 model number
    Affected if Device is a Schneider Electric Modicon M221 PLC
  2. Check PLC firmware version
    In EcoStruxure Machine Expert, navigate to PLC properties or system information to view the installed firmware version. If the PLC web server is enabled, access it and check the status or system information page for the firmware version
    Affected if Firmware version is below 1.6.2.0

The environment is affected if a Modicon M221 PLC is running firmware version lower than 1.6.2.0, as this version introduced secure password storage

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 1.6.2.0 or later
Fixed in 1.6.2.0
Interim mitigation

Update Modicon M221 firmware to V1.6.2.0 or later, which implements secure password storage. After updating, enforce strong password policies for all user accounts.

Fix this in Modicon M221 Firmware Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing4.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,720
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,752.

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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-2018-7792 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