# CVE-2013-6920: Auth bypass in n/a

> Remote attackers can bypass access restrictions on Siemens SINAMICS controllers by connecting to FTP or TELNET without authentication.

- **Severity:** Critical 10.0 (`AV:N/AC:L/Au:N/C:C/I:C/A:C`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Dec 2013
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-p6gr-96p8-25fw

## What is CVE-2013-6920?

CVE-2013-6920 is a critical authentication bypass vulnerability in n/a, published on 7 Dec 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Siemens SINAMICS S/G controllers with firmware before 4.6.11 do not require authentication for FTP and TELNET sessions, which allows remote attackers to bypass intended access restrictions via TCP traffic to port (1) 21 or (2) 23.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2013-6920?

It affects 14 products.


Products: Siemens Sinamics G110, Siemens Sinamics G110d, Siemens Sinamics G120, Siemens Sinamics G120c, Siemens Sinamics G120d, Siemens Sinamics G120p, Siemens Sinamics G130, Siemens Sinamics G150, Siemens Sinamics G180, Siemens Sinamics S110, Siemens Sinamics S120, Siemens Sinamics S120cm, Siemens Sinamics S150, Siemens Sinamics S\/G Family Firmware.

## How do I fix CVE-2013-6920?

No fix has been published for CVE-2013-6920 yet. Limit exposure of the affected software until one is available.

## Is CVE-2013-6920 being exploited?

There is no known exploitation of CVE-2013-6920 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2013-6920 and fix it if it is affected.

What it is: CVE-2013-6920 is a critical authentication bypass vulnerability in n/a, published on 7 Dec 2013. 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-2013-6920 in the wild and no public exploit code.

Affected product: n/a. 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-2013-6920/ (Markdown: https://insights.sbomify.com/CVE-2013-6920/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2013-6920
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2013-6920
- OSV: https://osv.dev/vulnerability/CVE-2013-6920

---
From sbomify Insights: https://insights.sbomify.com/CVE-2013-6920/
Summaries are generated and may contain mistakes; the official description above is the record.