# CVE-2020-28212: Auth bypass in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions)

> Attackers can execute unauthorized commands via brute force attacks on Modbus due to missing authentication attempt restrictions in the PLC Simulator.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Nov 2020
- **Updated:** 4 Aug 2024
- **Also known as:** GHSA-6pcj-rq2g-gx86

## What is CVE-2020-28212?

CVE-2020-28212 is a critical authentication bypass vulnerability in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions), published on 19 Nov 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A CWE-307: Improper Restriction of Excessive Authentication Attempts vulnerability exists in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) that could cause unauthorized command execution when a brute force attack is done over Modbus.

Weakness: CWE-307 (Improper Restriction of Excessive Authentication Attempts)

## Which versions are affected by CVE-2020-28212?

It affects 1 product.


Products: Schneider-Electric Ecostruxure Control Expert.

## How do I fix CVE-2020-28212?

No fix has been published for CVE-2020-28212 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-28212 being exploited?

There is no known exploitation of CVE-2020-28212 in the wild and no public exploit code.

## Other vulnerabilities in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions)

- [CVE-2022-37300](https://insights.sbomify.com/CVE-2022-37300/): Auth bypass in EcoStruxure Control Expert (critical 9.8)
- [CVE-2020-7475](https://insights.sbomify.com/CVE-2020-7475/): Code injection in EcoStruxure Control Expert (all versions prior to 14.1 Hot Fix), Unity Pro (all versions), Modicon M340 (all versions prior to V3.20), Modicon M580 (all versions prior to V3.10) (critical 9.8)
- [CVE-2023-27976](https://insights.sbomify.com/CVE-2023-27976/): Other in EcoStruxure Control Expert (high 8.8)
- [CVE-2020-28213](https://insights.sbomify.com/CVE-2020-28213/): Code injection in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions) (high 8.8)
- [CVE-2020-7560](https://insights.sbomify.com/CVE-2020-7560/): Memory corruption in EcoStruxure™ Control Expert (all versions) and Unity Pro (former name of EcoStruxure™ Control Expert) (all versions) (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2020-28212 and fix it if it is affected.

What it is: CVE-2020-28212 is a critical authentication bypass vulnerability in PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions), published on 19 Nov 2020. 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-2020-28212 in the wild and no public exploit code.

Affected product: PLC Simulator on EcoStruxureª Control Expert (now Unity Pro) (all versions). 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-2020-28212/ (Markdown: https://insights.sbomify.com/CVE-2020-28212/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-28212
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-28212
- OSV: https://osv.dev/vulnerability/CVE-2020-28212

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From sbomify Insights: https://insights.sbomify.com/CVE-2020-28212/
Summaries are generated and may contain mistakes; the official description above is the record.