# CVE-2017-16718: Weak cryptography in Beckhoff TwinCAT

> Attackers with network access can extract a fixed encryption key to bypass authentication in Beckhoff TwinCAT 3 ADS route configuration.

- **Severity:** Medium 5.9 (`CVSS:3.0/AV:N/AC:H/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:** 27 Jun 2018
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-wx26-fm45-hvxc

## What is CVE-2017-16718?

CVE-2017-16718 is a medium-severity vulnerability in ICS-CERT Beckhoff TwinCAT, published on 27 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Beckhoff TwinCAT 3 supports communication over ADS. ADS is a protocol for industrial automation in protected environments. This protocol uses user configured routes, that can be edited remotely via ADS. This special command supports encrypted authentication with username/password. The encryption uses a fixed key, that could be extracted by an attacker. Precondition of the exploitation of this weakness is network access at the moment a route is added.

Weakness: CWE-327 (Use of a Broken or Risky Cryptographic Algorithm), CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2017-16718?

It affects 1 product.


Products: Beckhoff Twincat.

## How do I fix CVE-2017-16718?

No fix has been published for CVE-2017-16718 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-16718 being exploited?

There is no known exploitation of CVE-2017-16718 in the wild and no public exploit code.

## Other vulnerabilities in ICS-CERT Beckhoff TwinCAT

- [CVE-2019-16871](https://insights.sbomify.com/CVE-2019-16871/): Auth bypass in n/a (critical 9.8)
- [CVE-2017-16726](https://insights.sbomify.com/CVE-2017-16726/): Weak cryptography in Beckhoff TwinCAT (critical 9.1)
- [CVE-2018-7502](https://insights.sbomify.com/CVE-2018-7502/): Privilege escalation in Beckhoff TwinCAT PLC products (high 7.8)
- [CVE-2019-5637](https://insights.sbomify.com/CVE-2019-5637/): Beckhoff TwinCAT Profinet Driver Divide-by-Zero Denial of Service (high 7.5)
- [CVE-2020-12494](https://insights.sbomify.com/CVE-2020-12494/): Beckhoff: Etherleak in TwinCAT RT network driver (medium 5.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-16718 and fix it if it is affected.

What it is: CVE-2017-16718 is a medium-severity vulnerability in ICS-CERT Beckhoff TwinCAT, published on 27 Jun 2018. 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-2017-16718 in the wild and no public exploit code.

Affected product: ICS-CERT Beckhoff TwinCAT. 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-2017-16718/ (Markdown: https://insights.sbomify.com/CVE-2017-16718/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-16718
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-16718
- OSV: https://osv.dev/vulnerability/CVE-2017-16718

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-16718/
Summaries are generated and may contain mistakes; the official description above is the record.