# CVE-2021-31228: Weak cryptography in n/a

> Attackers can predict DNS source ports to inject forged responses, bypassing DNS validation in HCC embedded InterNiche stacks.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 19 Aug 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-j7p3-x6j6-x86p

## What is CVE-2021-31228?

CVE-2021-31228 is a high-severity vulnerability in n/a, published on 19 Aug 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An issue was discovered in HCC embedded InterNiche 4.0.1. This vulnerability allows the attacker to predict a DNS query's source port in order to send forged DNS response packets that will be accepted as valid answers to the DNS client's requests (without sniffing the specific request). Data is predictable because it is based on the time of day, and has too few bits.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2021-31228?

It affects 1 product.


Products: Hcc-Embedded Nichestack.

## How do I fix CVE-2021-31228?

No fix has been published for CVE-2021-31228 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-31228 being exploited?

There is no known exploitation of CVE-2021-31228 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2020-35685](https://insights.sbomify.com/CVE-2020-35685/): Weak cryptography in n/a (critical 9.1)
- [CVE-2020-35683](https://insights.sbomify.com/CVE-2020-35683/): Memory corruption in n/a (high 7.5)
- [CVE-2020-35684](https://insights.sbomify.com/CVE-2020-35684/): Memory corruption in n/a (high 7.5)
- [CVE-2021-27565](https://insights.sbomify.com/CVE-2021-27565/): Denial of service in n/a (high 7.5)
- [CVE-2021-31227](https://insights.sbomify.com/CVE-2021-31227/): Memory corruption in n/a (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-31228 and fix it if it is affected.

What it is: CVE-2021-31228 is a high-severity vulnerability in n/a, published on 19 Aug 2021. 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-2021-31228 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-2021-31228/ (Markdown: https://insights.sbomify.com/CVE-2021-31228/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-31228
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-31228
- OSV: https://osv.dev/vulnerability/CVE-2021-31228

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-31228/
Summaries are generated and may contain mistakes; the official description above is the record.