One expired certificate cut mobile data in 11 countries at once

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One day. Mobile data fails in 11 countries at once. Same software. Same expired certificate.

6 December 2018. In the UK, O2's mobile data goes down. In Japan, 1:39 p.m. SoftBank's 4G is out. Nationwide. And it's not just them. Carriers in 11 countries.

In the UK, about 32 million people, The Register reported. Including giffgaff, Sky and Tesco Mobile users. In Japan, 4G was gone for four hours and 25 minutes. Traffic flooded into 3G. That jammed too.

The common thread? An Ericsson box in the core network, the heart of a mobile network. Ericsson's first finding: an expired certificate in the software. Operators on those versions failed together.

But here's the catch. That software had been running for nine months. Then a date inside it passed. The certificate expired.

So how did SoftBank get back? It put the older software version back. On every packet switch. 6:04 p.m. 4G is back. Ericsson says the faulty software is being retired.

A certificate inside shipped software is a timer nobody sees. Same version everywhere? It goes off everywhere. Track those dates too.

Full story in the article.