# CVE-2017-18371: Hardcoded credentials in n/a

> Attackers can use hardcoded default credentials to log in, change settings, and execute commands on ZyXEL routers.

- **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:** 2 May 2019
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-j9rw-cgp6-m49q

## What is CVE-2017-18371?

CVE-2017-18371 is a critical vulnerability in n/a, published on 2 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The ZyXEL P660HN-T1A v2 TCLinux Fw #7.3.37.6 router distributed by TrueOnline has three user accounts with default passwords, including two hardcoded service accounts: one with the username true and password true, and another with the username supervisor and password zyad1234. These accounts can be used to login to the web interface, exploit authenticated command injections, and change router settings for malicious purposes.

Weakness: CWE-798 (Use of Hard-coded Credentials)

## Which versions are affected by CVE-2017-18371?

It affects 3 products.


Products: Billion 5200w-T Firmware, Zyxel P660hn-T1a V1 Firmware, Zyxel P660hn-T1a V2 Firmware.

## How do I fix CVE-2017-18371?

No fix has been published for CVE-2017-18371 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-18371 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-18371 exists.

Public exploit code:

- TrueOnline / ZyXEL P660HN-T v2 Router Authenticated Command Injection (metasploit)

## Other vulnerabilities in n/a

- [CVE-2017-18368](https://insights.sbomify.com/CVE-2017-18368/): Zyxel P660HN-T1A Routers Command Injection (critical 9.8, exploited in the wild)
- [CVE-2017-18369](https://insights.sbomify.com/CVE-2017-18369/): Command injection in n/a (critical 9.8)
- [CVE-2017-18370](https://insights.sbomify.com/CVE-2017-18370/): Command injection in n/a (high 8.8)
- [CVE-2017-18372](https://insights.sbomify.com/CVE-2017-18372/): Command injection in n/a (high 8.8)
- [CVE-2017-18373](https://insights.sbomify.com/CVE-2017-18373/): Hardcoded credentials in n/a (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-18371 and fix it if it is affected.

What it is: CVE-2017-18371 is a critical vulnerability in n/a, published on 2 May 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2017-18371 exists.

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-2017-18371/ (Markdown: https://insights.sbomify.com/CVE-2017-18371/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-18371
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-18371
- OSV: https://osv.dev/vulnerability/CVE-2017-18371

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-18371/
Summaries are generated and may contain mistakes; the official description above is the record.