Spotting a Fake or Cloned IMEI: Warning Signs for Private Buyers
· TR Vertriebs GmbH
How to recognise during a used purchase that an IMEI may be manipulated or copied from another device.
The IMEI is the 15-digit serial number that uniquely identifies a mobile device on the network. For private buyers it is an important anchor when buying used: it reveals whether a device has been locked, reported stolen or relabelled. Fraudsters therefore occasionally try to fake an inconspicuous IMEI or take over the number of another device. You do not need technical skills to spot the warning signs — it is enough to run a few simple checks consistently and watch for contradictions.
The first step is to cross-check the number in several places. Dial *#06# on the device, note the IMEI shown and compare it with the settings (under Info or About phone), with the engraving on the SIM tray and with the sticker on the packaging. On modern devices with two SIM profiles, two IMEIs appear — that is normal. It becomes suspicious when the same spot shows different numbers, or when a label has obviously been stuck over.
The last digit of an IMEI is a check digit based on the Luhn algorithm. A correctly built IMEI passes this arithmetic test — but that only confirms the format, not authenticity. Even a completely invented number can pass the Luhn check if it was constructed to fit. So never rely on a number merely looking valid. Only cross-checking against the actual device and a status check against blacklist and manufacturer data gives a reliable picture.
The first eight digits of the IMEI form the Type Allocation Code (TAC) and encode the manufacturer and model. A simple plausibility test: does the model the TAC describes match the device in your hand? An iPhone whose IMEI points to a completely different model or manufacturer is a clear warning sign. An IMEI check resolves the TAC and shows the recorded model — you should take any discrepancy between the displayed and the actual device seriously.
Cloning copies the IMEI of a genuine device onto a second one. You obviously cannot see that second device, but there are indirect clues: a device whose IMEI already appears as stolen or blocked even though the seller insists everything is fine; recurring network problems; or an IMEI that shows up in a check with contradictory status information. Caution is also warranted whenever a seller cannot explain where the device came from.
Pay attention to behaviour and surrounding circumstances too. Warning signs include a scratched or clearly replaced label, a refusal to dial *#06# on the spot, packaging with a different number, a price well below market value, a missing invoice, or pressure to close quickly. Individually, none of these has to mean anything — but when they pile up, you should question the purchase.
When in doubt: check first, pay later. Have the IMEI shown directly on the device via *#06#, run a status check with it and compare the result with the visible model. If something does not add up and the seller cannot explain it convincingly, walking away is the safest decision. If you do buy, keep receipts, chat logs and the verified IMEI — that helps if questions come up later.