# CVE-2017-16743: Auth bypass in PHOENIX CONTACT FL SWITCH

> Remote attackers can bypass web-service authentication to gain administrative privileges on PHOENIX CONTACT industrial switches.

- **Severity:** Critical 9.8 (`CVSS:3.0/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:** 12 Jan 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-xp4q-qhv3-758q

## What is CVE-2017-16743?

CVE-2017-16743 is a critical authentication bypass vulnerability in PHOENIX CONTACT FL SWITCH, published on 12 Jan 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An Improper Authorization issue was discovered in PHOENIX CONTACT FL SWITCH 3xxx, 4xxx, and 48xxx Series products running firmware Version 1.0 to 1.32. A remote unauthenticated attacker may be able to craft special HTTP requests allowing an attacker to bypass web-service authentication allowing the attacker to obtain administrative privileges on the device.

Weakness: CWE-863 (Incorrect Authorization), CWE-285 (Improper Authorization)

## Which versions are affected by CVE-2017-16743?

It affects 29 products.


Products: Phoenixcontact Fl Switch 3004t-Fx Firmware, Phoenixcontact Fl Switch 3004t-Fx St Firmware, Phoenixcontact Fl Switch 3005 Firmware, Phoenixcontact Fl Switch 3005t Firmware, Phoenixcontact Fl Switch 3006t-2fx Firmware, Phoenixcontact Fl Switch 3006t-2fx Sm Firmware, Phoenixcontact Fl Switch 3006t-2fx St Firmware, Phoenixcontact Fl Switch 3008 Firmware, Phoenixcontact Fl Switch 3008t Firmware, Phoenixcontact Fl Switch 3012e-2fx Sm Firmware, Phoenixcontact Fl Switch 3012e-2sfx Firmware, Phoenixcontact Fl Switch 3016 Firmware, Phoenixcontact Fl Switch 3016e Firmware, Phoenixcontact Fl Switch 3016t Firmware, Phoenixcontact Fl Switch 4000t-8poe-2sfp-R Firmware, Phoenixcontact Fl Switch 4008t-2gt-3fx Sm Firmware, Phoenixcontact Fl Switch 4008t-2gt-4fx Sm Firmware, Phoenixcontact Fl Switch 4008t-2sfp Firmware, Phoenixcontact Fl Switch 4012t-2gt-2fx St Firmware, Phoenixcontact Fl Switch 4012t 2gt 2fx Firmware and 9 more.

## How do I fix CVE-2017-16743?

No fix has been published for CVE-2017-16743 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-16743 being exploited?

There is no known exploitation of CVE-2017-16743 in the wild and no public exploit code.

## Other vulnerabilities in PHOENIX CONTACT FL SWITCH

- [CVE-2018-10730](https://insights.sbomify.com/CVE-2018-10730/): Command injection in n/a (critical 9.1)
- [CVE-2018-10731](https://insights.sbomify.com/CVE-2018-10731/): Memory corruption in n/a (critical 9.0)
- [CVE-2018-13993](https://insights.sbomify.com/CVE-2018-13993/): Cross-site request forgery in n/a (high 8.8)
- [CVE-2018-13990](https://insights.sbomify.com/CVE-2018-13990/): Auth bypass in n/a (high 8.6)
- [CVE-2018-13992](https://insights.sbomify.com/CVE-2018-13992/): Information disclosure in n/a (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-16743 and fix it if it is affected.

What it is: CVE-2017-16743 is a critical authentication bypass vulnerability in PHOENIX CONTACT FL SWITCH, published on 12 Jan 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-2017-16743 in the wild and no public exploit code.

Affected product: PHOENIX CONTACT FL SWITCH. 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-2017-16743/ (Markdown: https://insights.sbomify.com/CVE-2017-16743/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-16743
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-16743
- OSV: https://osv.dev/vulnerability/CVE-2017-16743

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-16743/
Summaries are generated and may contain mistakes; the official description above is the record.