title: Telenot complex: Insecure AES Key Generation
description: Telenot CompasX versions prior to 32.0 use a weak seed for random number generation leading to predictable AES keys used in the NFC tags used for local authorization of users. This may lead to total loss of trustworthiness of the installation.
problem types: CWE-335 Incorrect Usage of Seeds in Pseudo-Random Number Generator (PRNG)
affected:
{
defaultStatus: unaffected
product: CompasX
vendor: Telenot Electronic GmbH
versions:
lessThan: 32.0, status: affected, version: unspecified, versionType: custom
}
metrics:
cvssV3_1: [
attackComplexity: LOW
attackVector: LOCAL
availabilityImpact: NONE
baseScore: 5.5
baseSeverity: MEDIUM
confidentialityImpact: HIGH
integrityImpact: NONE
privilegesRequired: LOW
scope: UNCHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
version: 3.1
]
format: CVSS
scenarios: GENERAL
solutions: Update to CompasX versions >= 32.0
workarounds: It is strongly recommended to raise the security level during the time window until the AES keys can be changed to securely generated ones. The complex alarm systems supports alternative authentication factors that can be combined with the Desfire NFC tag authentication. An example for such an additional factor is a requirement for a valid PIN entry on the complex alarm system in addition to a successful Desfire authentication to disarm the alarm.