# CVE-2021-23842: Use of Hard-coded Cryptographic Key

> An attacker on the local network can extract a hardcoded key to decrypt traffic and modify device configuration.

- **Severity:** Medium 5.7 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 19 Jan 2022
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-j6hr-vmm6-m6c2

## What is CVE-2021-23842?

CVE-2021-23842 is a medium-severity vulnerability in Bosch AMC2, published on 19 Jan 2022. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Communication to the AMC2 uses a state-of-the-art cryptographic algorithm for symmetric encryption called Blowfish. An attacker could retrieve the key from the firmware to decrypt network traffic between the AMC2 and the host system. Thus, an attacker can exploit this vulnerability to decrypt and modify network traffic, decrypt and further investigate the device\'s firmware file, and change the device configuration. The attacker needs to have access to the local network, typically even the same subnet.

Weakness: CWE-798 (Use of Hard-coded Credentials), CWE-321 (Use of Hard-coded Cryptographic Key)

## Which versions are affected by CVE-2021-23842?

It affects 4 products.


Products: Bosch Access Management System, Bosch Access Professional Edition, Bosch Amc2 Firmware, Bosch Building Integration System.

## How do I fix CVE-2021-23842?

No fix has been published for CVE-2021-23842 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-23842 being exploited?

There is no known exploitation of CVE-2021-23842 in the wild and no public exploit code.

## Other vulnerabilities in Bosch AMC2

- [CVE-2021-23843](https://insights.sbomify.com/CVE-2021-23843/): Lack of authentication mechanisms on the device (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-23842 and fix it if it is affected.

What it is: CVE-2021-23842 is a medium-severity vulnerability in Bosch AMC2, published on 19 Jan 2022. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-23842 in the wild and no public exploit code.

Affected product: Bosch AMC2. 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-2021-23842/ (Markdown: https://insights.sbomify.com/CVE-2021-23842/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-23842
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-23842
- OSV: https://osv.dev/vulnerability/CVE-2021-23842

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-23842/
Summaries are generated and may contain mistakes; the official description above is the record.