The Expired Certificate That Silenced 11 Countries
01:10 · Point of failure
On 6 December 2018, an expired certificate in Ericsson core-network software disrupted operators across 11 countries. O2 and SoftBank were among the networks affected by the same dated dependency.
Editions
- Watch
- The episode on YouTube1:40
- Read
- The technical debrief on ZOF.aizof.ai
Incident
- Topics
- certificate expiry · telecom · shared dependencies · reliability
- Point of failure
- The certificate's expiry date was written down years in advance, and no system or person was watching the calendar for it.
Transcript
The outage
Tens of millions of phones in two countries lost data on the same morning. The cause had been scheduled for years. This is The Point of Failure, episode twelve.
December 6th, 2018. In the UK, O2's network wakes up broken. No mobile data for tens of millions. Buses can't show arrival times. Card machines fail. And weirdly at the same time, Japan. SoftBank. Same morning, same failure.
Two countries, one cause. Both networks ran core software from Ericsson. And inside the software sat a digital certificate. A certificate is like an ID card that machines show each other to prove they can be trusted. And every ID card has an expiry date printed on it the day it is issued.
The expiry date
The date arrived and the certificate expired. And the machines did exactly what they were designed to do with an expired ID. They stopped trusting each other. The network did not break. It refused.
Watching the calendar
Point of failure
A full day to restore. Compensation reportedly in the tens of millions. And the maddening part, an expiry date is the single most predictable event in computing. It is literally written down years in advance. It just needed one system or one person watching the calendar.
Every failure has a story. Every story was preventable. I'm Kevin. See you at the next one.
Sources
O2 poised to receive millions from Ericsson over software failure
Compensation was reported as prospective, not a confirmed settlement.
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