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IT and securityLesson 3 of 3

Part 1 of 3, 0 done

14 min

When it goes wrong: an outage or a breach

One morning the computers won't start, or a stranger is inside them. What happens next is a plan written long before: who's in charge, what to switch off, who to call, and what to tell customers.

Ticket 01 · The guess

What did one bad update cost an airline?

On a Friday in July 2024, a faulty software update crashed Windows computers around the world. Delta Air Lines, one of the biggest US airlines, canceled flights for days. How much revenue did Delta say the outage cost it directly?

$1B
$0$2B
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Sources and every number (2)

Sources

  • Delta Air Lines Announces September Quarter 2024 Financial Results (10 October 2024): financial impact of the CrowdStrike-caused outage · Delta Air Lines, 2024
  • Helping our customers through the CrowdStrike outage (David Weston, 20 July 2024) · Microsoft, 2024

Every number

  • $380Mdelta.com ·2024 · Delta's "direct revenue impact" of the CrowdStrike-caused outage in the September quarter of 2024, about this much, mostly refunds and customer compensation (its results release).
  • $170Mdelta.com ·2024 · The outage's non-fuel expense impact, mostly reimbursing customers' expenses and crew costs, September quarter 2024.
  • $50Mdelta.com ·2024 · How much lower Delta's fuel expense was because of the canceled flights, September quarter 2024.
  • 7,000 flight cancellationsdelta.com ·2024 · Flights Delta canceled over the outage's five days, July 2024.
  • 8.5 million Windows devicesmicrosoft.com ·2024 · Microsoft's estimate of the Windows devices the CrowdStrike update affected, published the day after the outage, July 2024.
  • 1%microsoft.com ·2024 · Microsoft: the devices affected were less than this share of all Windows machines.
  1. Lessons›
  2. Inside a business›
  3. IT and security
  • ·Before this: Phishing, passwords and backups
Skip to the lesson

IT and securityLesson 3 of 3

Part 1 of 3, 0 done

14 min

When it goes wrong: an outage or a breach

One morning the computers won't start, or a stranger is inside them. What happens next is a plan written long before: who's in charge, what to switch off, who to call, and what to tell customers.

Ticket 01 · The guess

What did one bad update cost an airline?

On a Friday in July 2024, a faulty software update crashed Windows computers around the world. Delta Air Lines, one of the biggest US airlines, canceled flights for days. How much revenue did Delta say the outage cost it directly?

$1B
$0$2B
Words to know

Spot something wrong?

Tell us what looks off. No name or email needed.

What kind of problem?

0 / 1000

We'll also send this page, the lesson, ticket 1, so we can find it. Nothing else. Privacy

·
Sources and every number (2)

Sources

  • Delta Air Lines Announces September Quarter 2024 Financial Results (10 October 2024): financial impact of the CrowdStrike-caused outage · Delta Air Lines, 2024
  • Helping our customers through the CrowdStrike outage (David Weston, 20 July 2024) · Microsoft, 2024

Every number

  • $380Mdelta.com ·2024 · Delta's "direct revenue impact" of the CrowdStrike-caused outage in the September quarter of 2024, about this much, mostly refunds and customer compensation (its results release).
  • $170Mdelta.com ·2024 · The outage's non-fuel expense impact, mostly reimbursing customers' expenses and crew costs, September quarter 2024.
  • $50Mdelta.com ·2024 · How much lower Delta's fuel expense was because of the canceled flights, September quarter 2024.
  • 7,000 flight cancellationsdelta.com ·2024 · Flights Delta canceled over the outage's five days, July 2024.
  • 8.5 million Windows devicesmicrosoft.com ·2024 · Microsoft's estimate of the Windows devices the CrowdStrike update affected, published the day after the outage, July 2024.
  • 1%microsoft.com ·2024 · Microsoft: the devices affected were less than this share of all Windows machines.
  1. Lessons›
  2. Inside a business›
  3. IT and security
  • ·Before this: Phishing, passwords and backups