Morris worm turns 20: Look what it's done

First Internet attack spawned panic, public awareness and security research

Previously, researchers had been developing benevolent worms that could be used to automatically install software updates, but no one had launched a malicious worm onto a network in an uncontrolled fashion.

The Morris worm served as a precursor to other well-known worm attacks including 1999's Melissa, 2001's Code Red and 2003's Slammer, all of which targeted systems running Microsoft software.

Lately worms have been less popular attacks than viruses or e-mails with URLs that point to malicious Web sites.

"Worms are actually relatively rare compared to the number of virus attacks," Allman says. "For the average user, phishing is a worse problem."

"We haven't seen a big Internet-clogging worm in several years, and there are several reasons for that including the increasing prevalence of [network address translation] boxes and personal firewalls that make it difficult for a worm to do the scanning the way the Morris worm did," Bellovin says.

The Morris worm foreshadowed how future distributed denial-of-service attacks would be used to overload systems and knock them off the Internet.

"There had never been a simultaneous large-scale security event prior to that," Spafford says. "It was the first significant denial-of-service issue that came to people's attention related to computing. And it was the first event that crossed vendor platforms because it attacked Berkeley Unix and Sun systems, and in that regard I would say we haven't seen many other incidents like that. Most incidents have been directed at one vendor's platform."

Spafford likens the Morris worm to today's botnets, which are large volumes of compromised computers used to send spam.

"The software that turns systems into zombies and adds them to botnets are like slow-moving worms," Spafford says. "They don't cause a denial of service, but they do create a slow infiltration and they spread to other machines automatically. There are quite literally millions of machines -- some estimates are 100 million machines -- that are inside botnets."

While the Morris worm was a high-profile attack that took down large swaths of the Internet, today's Internet attacks are focused on individual systems and tend to be stealthy. Instead of curious college students breaking into systems for bragging rights, it's more common to see criminals infect systems with viruses designed to be invisible.

Join the PC World newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags morris worm

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Carolyn Duffy Marsan

Network World
Show Comments

Most Popular Reviews

Latest Articles


PCW Evaluation Team

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Armand Abogado

HP OfficeJet 250 Mobile Printer

Wireless printing from my iPhone was also a handy feature, the whole experience was quick and seamless with no setup requirements - accessed through the default iOS printing menu options.

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?