title: Keystream recovery for arbitrary frames in TETRA
description: Adversary-induced keystream re-use on TETRA air-interface encrypted traffic using any TEA keystream generator. IV generation is based upon several TDMA frame counters, which are frequently broadcast by the infrastructure in an unauthenticated manner. An active adversary can manipulate the view of these counters in a mobile station, provoking keystream re-use. By sending crafted messages to the MS and analyzing MS responses, keystream for arbitrary frames can be recovered.
problem types: Reusing a Nonce, Key Pair in Encryption
affected:
{
defaultStatus: affected
vendor: ETSI
product: TETRA Standard
versions:
version: all, 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
]