# CVE-2021-20827: Hardcoded credentials in IDEC PLC

> Attackers can extract plaintext PLC credentials from backup files to hijack the PLC, manipulate outputs, or suspend operations.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Dec 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-hxfc-cc7r-hxxv

## What is CVE-2021-20827?

CVE-2021-20827 is a high-severity vulnerability in IDEC PLC, published on 24 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Plaintext storage of a password vulnerability in IDEC PLCs (FC6A Series MICROSmart All-in-One CPU module v2.32 and earlier, FC6A Series MICROSmart Plus CPU module v1.91 and earlier, WindLDR v8.19.1 and earlier, WindEDIT Lite v1.3.1 and earlier, and Data File Manager v2.12.1 and earlier) allows an attacker to obtain the PLC Web server user credentials from file servers, backup repositories, or ZLD files saved in SD cards. As a result, the attacker may access the PLC Web server and hijack the PLC, and manipulation of the PLC output and/or suspension of the PLC may be conducted.

Weakness: CWE-312 (Cleartext Storage of Sensitive Information)

## Which versions are affected by CVE-2021-20827?

It affects 5 products.


Products: Idec Data File Manager, Idec Microsmart Fc6a Firmware, Idec Microsmart Plus Fc6a Firmware, Idec Windedit, Idec Windldr.

## How do I fix CVE-2021-20827?

No fix has been published for CVE-2021-20827 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-20827 being exploited?

There is no known exploitation of CVE-2021-20827 in the wild and no public exploit code.

## Other vulnerabilities in IDEC PLC

- [CVE-2021-37400](https://insights.sbomify.com/CVE-2021-37400/): Information disclosure in n/a (critical 9.8)
- [CVE-2021-37401](https://insights.sbomify.com/CVE-2021-37401/): Information disclosure in n/a (critical 9.8)
- [CVE-2021-20826](https://insights.sbomify.com/CVE-2021-20826/): Information disclosure in IDEC PLC (high 7.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-20827 and fix it if it is affected.

What it is: CVE-2021-20827 is a high-severity vulnerability in IDEC PLC, published on 24 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-20827 in the wild and no public exploit code.

Affected product: IDEC PLC. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-20827/ (Markdown: https://insights.sbomify.com/CVE-2021-20827/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-20827
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-20827
- OSV: https://osv.dev/vulnerability/CVE-2021-20827

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-20827/
Summaries are generated and may contain mistakes; the official description above is the record.