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

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2022-01-19 · updated 2026-06-17
Weakness: CWE-321

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.

Affected products

Bosch Access Management System: 3.0
Bosch Access Professional Edition: through 3.8.0
Bosch Amc2 Firmware: all versions
Bosch Building Integration System: before 4.9.1 — fixed in 4.9.1

How to fix

Upgrade to a fixed version: Bosch Building Integration System 4.9.1. Check the vendor advisory for mitigations.

References

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