DENSO CORPORATION — 3 MA-L + 1 MA-S; automotive Tier-1, OUI = in-vehicle/V2X gear

DENSO CORPORATION, the Toyota Group Tier-1 automotive components supplier, holds three MA-L (24-bit) blocks in the IEEE registry: 00:C0:59 and 18:95:78, both registered to "DENSO CORPORATION" at the 1-1 Showa-cho, Kariya-shi, Aichi 448-8661 headquarters, plus 0C:01:C8, registered to "DENSO Co.,Ltd" at an Osaka office (Twin21 MIDTower, Shiromi, Chuo-ku). A US manufacturing subsidiary, Denso Manufacturing Tennessee, holds one MA-S (36-bit) block, 8C:1F:64:35:8 (Maryville, TN). Two related but distinct legal entities also appear and should not be folded into core DENSO CORPORATION: FUJITSU DENSO LTD. (00:A0:CA, a Fujitsu-Denso joint entity at a San Jose, CA address) and Nippon Denso Industry Co., Ltd. (00:0F:FB, Tokyo). The registered OUIs are used on automotive embedded network hardware — telematics control units (DCM), V2X on-board units (DSRC IEEE 802.11p plus C-V2X dual-mode), eCall units, ECUs, and connected-cockpit modules — not on general-purpose IT equipment, so a DENSO OUI on a scan most likely indicates an in-vehicle telematics/V2X module or an automotive diagnostic tool. No MA-M blocks exist. IEEE publishes no registration dates; any third-party "date registered" value is a database artifact.

IEEE assignment

3 MA-L prefixes → DENSO (00:C0:59 and 18:95:78 → "DENSO CORPORATION", Kariya HQ; 0C:01:C8 → "DENSO Co.,Ltd", Osaka office) [Confirmed] — IEEE MA-L (oui.csv lines 6356, 7473, 63)

Registry / block size

MA-L (24-bit OUI), 3 blocks; plus one MA-S (36-bit) block held by a US subsidiary [Confirmed] — IEEE oui.csv, oui36.csv; maclookup.app (IEEE-sourced)

HQ / country

1-1, Showa-cho, Kariya-shi, Aichi 448-8661, JP (registry address for the two core DENSO CORPORATION blocks) [Confirmed] — IEEE MA-L, denso.com

MA-S block

8C:1F:64:35:8 → "Denso Manufacturing Tennessee", 1720 Robert C. Jackson Drive, Maryville, TN 37801, US — extended 36-bit assignment held by the US manufacturing subsidiary, not the parent [Confirmed] — IEEE oui36.csv (line 2852)

MA-M

none — no DENSO entry in mam.csv (MA-M) in the cached registries [Confirmed] — IEEE mam.csv

Related but distinct registrants (do NOT merge into core DENSO CORPORATION)

FUJITSU DENSO LTD. → 00:A0:CA (Fujitsu+Denso joint entity, San Jose CA address); Nippon Denso Industry Co., Ltd. → 00:0F:FB (Tokyo subsidiary/related entity) [Confirmed] — IEEE oui.csv (lines 6256, 28878)

Company status

active; major Japanese Tier-1 automotive components supplier, Toyota Group affiliate (Toyota Motor Corp. holds ~21%), founded 1949, HQ Kariya, Aichi [Confirmed] — en.wikipedia.org/wiki/Denso, denso.com

Device types

automotive electronics — telematics control units (DCM), V2X on-board units (OBU, DSRC + C-V2X dual-mode), eCall units, ECUs/ECMs, EV battery-monitoring ECUs, head-up displays, instrument clusters, pre-crash radar, roadside units (RSU). Networked in-vehicle/roadside devices, not general-purpose IT hardware. [Confirmed] — denso.com (safety-cockpit), telematicswire.net, westernsystems-inc.com

Connectivity

DSRC (IEEE 802.11p / WAVE), C-V2X (cellular / 5G NR-V2X), LTE, GNSS; in-vehicle CAN bus and automotive Ethernet; V2X OBU integrates a hardware security module (HSM) [Confirmed] — westernsystems-inc.com, telematicswire.net

Verified prefix sample

00:C0:59, 18:95:78, 0C:01:C8 (MA-L); 8C:1F:64:35:8 (MA-S) [Confirmed] — IEEE oui.csv / oui36.csv

CID note

maclookup.app also lists BA:FE:3A as a DENSO CID (Company ID) — a company-internal-use identifier, NOT a globally-unique OUI; it should not be treated as a standard vendor prefix [Likely] — maclookup.app/vendors/denso-corporation

Security note

no product-level CVEs for DENSO network devices surfaced in public NVD/JVNDB searches this pass. Two public incidents were corporate-IT ransomware breaches, not in-vehicle/OT product flaws: Rook (Dec 2021, DENSO Mexico, ~1.1 TB) and Pandora (Mar 2022, Denso Automotive Deutschland GmbH, ~1.4 TB of drawings/POs); no production disruption reported. [Confirmed for the incidents; Unknown for product-level CVEs] — bleepingcomputer.com, cpomagazine.com, bankinfosecurity.com

Special note

OUI = in-vehicle / V2X automotive gear. A DENSO OUI most often appears on a telematics module, V2X OBU/RSU, ECU, or connected-cockpit unit — or an automotive development/diagnostic tool — not on consumer IT or general networking gear. IEEE publishes no assignment dates; third-party "date registered" values (e.g. maclookup.app shows 1998-04-22 for 00:C0:59 and 2023-10-19 for 18:95:78) are database artifacts, not IEEE facts. [Confirmed]

Related vendors / subsidiaries

DENSO TEN Limited (formerly Fujitsu Ten; infotainment/telematics, eCall TCUs); Denso Wave (invented the QR code in 1994; industrial barcode/RFID readers may also carry DENSO prefixes); FUJITSU DENSO LTD. and Nippon Denso Industry hold their own separate registrations [Confirmed] — en.wikipedia.org/wiki/Denso_Ten, en.wikipedia.org/wiki/Denso

Analyst note

A DENSO OUI (00:C0:59, 18:95:78, 0C:01:C8) most likely identifies in-vehicle telematics/V2X hardware or an automotive diagnostic tool, not a standard LAN endpoint. The MA-S block 8C:1F:64:35:8 narrows to the Tennessee manufacturing site. Treat FUJITSU DENSO and Nippon Denso Industry as separate registrants.