CVE-2022-26943 (mtm5400_firmware, mtm5500_firmware)

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 …

adversary attacks authentication challenge challenges cve entropy low motorola prng register series tetra tick vulnerable