title: Weak PRNG entropy source used for authentication challenge generation in Motorola MTM5000
description: The Motorola MTM5000 series firmwares generate TETRA authentication challenges using a PRNG using a tick count register as its sole entropy source. Low boottime entropy and limited re-seeding of the pool renders the authentication challenge vulnerable to two attacks. First, due to the limited boottime pool entropy, an adversary can derive the contents of the entropy pool by an exhaustive search of possible values, based on an observed authentication challenge. Second, an adversary can use knowledge of the entropy pool to predict authentication challenges. As such, the unit is vulnerable to CVE-2022-24400.
problem types: Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG)
affected:
{
vendor: Motorola
product: Mobile Radio
versions:
version: MTM5000, status: affected
}
metrics:
format: CVSS
scenarios: GENERAL
cvssV3_1: [
version: 3.1
attackVector: ADJACENT_NETWORK
attackComplexity: LOW
privilegesRequired: NONE
userInteraction: NONE
scope: UNCHANGED
confidentialityImpact: HIGH
integrityImpact: HIGH
availabilityImpact: HIGH
baseScore: 8.8
baseSeverity: CRITICAL
vectorString: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:U/RC:C/CR:H/IR:H/AR:H/MAV:A/MAC:L/MPR:N/MUI:N/MS:U/MC:H/MI:H/MA:H
]