Table of Contents
TL;DR
The ILOVEYOU virus did not destroy our data. It destroyed our email system by using it. The worm sent so much mail through our early Exchange server that it ran out of disk space and crashed. Recovery took weeks: isolating the cause, purging queues by hand, and coordinating a company that suddenly had no email, by walking around and talking to people.
Before ransomware, before phishing kits, there was ILOVEYOU, one of the first genuinely destructive mass-mailing worms. When it hit us, it hit every system, but its real damage was not to the machines it infected. Its damage was volume. The worm mailed itself to everyone in every address book it touched, and it did that from hundreds of machines at once.
We were running an early version of Exchange, and it choked. The flood of outbound mail was so large that the server ran out of disk space and crashed. Our email system was killed by our own email.
Sneakernet
With email down company-wide, coordination reverted to what we used to call sneakernet: put on your sneakers and walk to the person you need. Every question that would have been a two-line email became a trip across the building. The whole company slowed to the speed of hallway conversations, which is a thing you do not fully appreciate until it happens. The outage was not an IT inconvenience; it stalled the business.
That experience permanently changed how I think about email. It is not a communication tool among many. For most companies it is the nervous system, and when the nervous system goes down, the organization discovers it cannot move.
No playbook, no precedent
What is hard to convey now is how alone you were in an outbreak then. There was no threat-intelligence feed pushing indicators to your dashboard, no vendor bulletin arriving ahead of the malware, no incident-response retainer to call. Antivirus signatures for a new worm lagged its spread by days, which during ILOVEYOU meant the entire event. You diagnosed by symptom: the mail queues exploding, the same subject line multiplying, users calling about a message from a colleague that seemed off. We were writing the playbook while the building burned, and so was every other company on the planet that week.
I keep that memory around as a calibration. Modern security teams drown in intelligence and sometimes envy a simpler era. The simpler era was worse. Information asymmetry favored the worm completely, and the defenders’ only real-time network was the telephone.
ILOVEYOU never touched our data. It buried our Exchange server under its own outbound mail until the disks filled and it died.Share on X
Weeks, not days
Recovery took weeks, and it came in ugly layers. First, we had to figure out what was happening at all, in an era when there was no threat-intel feed telling you a worm was circling the planet. Then we had to stop the reinfection cycle: clean one machine and its infected neighbors would reinfect it before the technician reached the next desk. The eventual answer was segmentation used as a treatment instead of a defense: we created a clean subnet and moved disinfected machines into it, so the cured population could not be touched by the sick one. The infected side shrank machine by machine until it was gone.
The server itself was its own project. We did not restore from backup. We went into the Exchange queues and purged them by hand, a procedure we first had to research and then perform on a production system holding the company’s mail. Delete the worm’s traffic, preserve the legitimate mail, free the disks, bring the server back. Then watch it, because if one infected machine remained, the flood would resume.
What ILOVEYOU taught that still applies
First: availability is a security property. Nothing was encrypted, nothing was stolen, and we still lost weeks, because the attack consumed a resource. Modern denial-of-service thinking starts exactly here.
Second: reinfection is the real enemy of cleanup. Any recovery plan that cleans machines one at a time inside a connected population is a plan to clean the same machines repeatedly. You separate clean from dirty first, then you cure.
Third: have a fallback channel. Every incident-response plan that assumes email works should be assumed broken. Ours was walking. Yours should be better than walking.
For an executive writing about resilience, this era is a gift. Stories from the early worm outbreaks show readers the anatomy of a crisis without the fog of modern complexity: one worm, one server, one company relearning how to talk to itself.
For more from this series, see the The Cybersecurity Hub: breaches, audits, and hard-won security lessons from four decades in the trenches.
The Guides That Get Your Book Written, Published, and Sold
Four short, practical guides on writing, publishing, and selling your book, plus the occasional note when there's something worth your time. No fluff, no daily inbox clutter. Drop your email and they're yours.
We use MailerLite to manage our list and send these emails. Your address is used only to send you what you signed up for. We will not sell it, share it, or use it for anything else, and you can unsubscribe anytime.