CVE-2021-37401

PLC program alteration via plaintext project credentials

Published Dec 28, 2021 · Updated Aug 4, 2024

Cleartext credential storage in IDEC PLC project files allows attackers to obtain credentials and alter PLC user programs. WindLDR, WindEDIT Lite, and Data File Manager store PLC credentials unencrypted inside ZLD files copied to file servers, backup repositories, or SD cards. Access to a ZLD file is required; the recovered credentials permit PLC user-program upload, alteration, and download.

CVSS severity7.6
High
EPSS probability1.34%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cleartext credential storage in IDEC PLC project files allows attackers to obtain credentials and alter PLC user programs. WindLDR, WindEDIT Lite, and Data File Manager store PLC credentials unencrypted inside ZLD files copied to file servers, backup repositories, or SD cards. Access to a ZLD file is required; the recovered credentials permit PLC user-program upload, alteration, and download.

The record

CVE
CVE-2021-37401
Published
Dec 28, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-522, CWE-256, T1555
Attack vector
Unavailable
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 28, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.6JPCERT/CC and IPACVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
CWE-256Plaintext Storage of a Password
T1555Credentials from Password Stores: Credentials from Password Stores

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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