# CVE-2017-2684: Auth bypass in SIMATIC Logon All versions < V1.5 SP3 Update 2

> An attacker with valid username knowledge and access can bypass application-level authentication in Siemens SIMATIC Logon.

- **Severity:** Critical 9.0 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/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:** 22 Feb 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-h5v3-4rh5-mj9g

## What is CVE-2017-2684?

CVE-2017-2684 is a critical authentication bypass vulnerability in SIMATIC Logon All versions < V1.5 SP3 Update 2, published on 22 Feb 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Siemens SIMATIC Logon prior to V1.5 SP3 Update 2 could allow an attacker with knowledge of a valid user name, and physical or network access to the affected system, to bypass the application-level authentication.

Weakness: CWE-592 (DEPRECATED: Authentication Bypass Issues)

## Which versions are affected by CVE-2017-2684?

It affects 1 product.


Products: Siemens Simatic Logon.

## How do I fix CVE-2017-2684?

No fix has been published for CVE-2017-2684 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-2684 being exploited?

There is no known exploitation of CVE-2017-2684 in the wild and no public exploit code.

## Other vulnerabilities in SIMATIC Logon All versions < V1.5 SP3 Update 2

- [CVE-2017-9938](https://insights.sbomify.com/CVE-2017-9938/): Denial of service in SIMATIC Logon All versions before V1.6 (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-2684 and fix it if it is affected.

What it is: CVE-2017-2684 is a critical authentication bypass vulnerability in SIMATIC Logon All versions < V1.5 SP3 Update 2, published on 22 Feb 2017. 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-2017-2684 in the wild and no public exploit code.

Affected product: SIMATIC Logon All versions < V1.5 SP3 Update 2. 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-2017-2684/ (Markdown: https://insights.sbomify.com/CVE-2017-2684/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-2684
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-2684
- OSV: https://osv.dev/vulnerability/CVE-2017-2684

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-2684/
Summaries are generated and may contain mistakes; the official description above is the record.