# CVE-2017-16778: Auth bypass in n/a

> Physical attackers can inject DTMF tones to bypass access controls and gain unauthorized entry to restricted floors.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 24 Dec 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-54w4-4qgr-936w

## What is CVE-2017-16778?

CVE-2017-16778 is a medium-severity authentication bypass vulnerability in n/a, published on 24 Dec 2019. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

An access control weakness in the DTMF tone receiver of Fermax Outdoor Panel allows physical attackers to inject a Dual-Tone-Multi-Frequency (DTMF) tone to invoke an access grant that would allow physical access to a restricted floor/level. By design, only a residential unit owner may allow such an access grant. However, due to incorrect access control, an attacker could inject it via the speaker unit to perform an access grant to gain unauthorized access, as demonstrated by a loud DTMF tone representing '1' and a long '#' (697 Hz and 1209 Hz, followed by 941 Hz and 1477 Hz).

Weakness: CWE-863 (Incorrect Authorization)

## Which versions are affected by CVE-2017-16778?

It affects 1 product.


Products: Fermax Outdoor Panel Firmware.

## How do I fix CVE-2017-16778?

No fix has been published for CVE-2017-16778 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-16778 being exploited?

There is no known exploitation of CVE-2017-16778 in the wild and no public exploit code.

Public exploit code:

- A coordinated disclosure and security advisory on Fermax Intercom DTML Injection vulneraiblity. Special thanks to Fermax International for prompt responses and allowing details to be publicized. (github_poc): https://github.com/breaktoprotect/CVE-2017-16778-Intercom-DTMF-Injection

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-16778 and fix it if it is affected.

What it is: CVE-2017-16778 is a medium-severity authentication bypass vulnerability in n/a, published on 24 Dec 2019. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-16778 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-2017-16778/ (Markdown: https://insights.sbomify.com/CVE-2017-16778/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-16778
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-16778
- OSV: https://osv.dev/vulnerability/CVE-2017-16778

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-16778/
Summaries are generated and may contain mistakes; the official description above is the record.