Doorkeeper

How Reasonable Decisions Created a Security Incident

Thu, 26 Nov 2026 18:30 - 21:00 JST

OPTiM Tokyo

〒105-0022 Tokyo, Minato City, Kaigan, 1 Chome−2−20 汐留ビルディング 18F

Register
Free admission
Registration closes 26 Nov 21:00
There is room for 53 more people

Description

New Venue!
Please take note that the venue for this event is OPTiM Tokyo!

Agenda

18:30 〜 19:00 Doors open

Grab a drink, grab some stickers, and catch up with your fellow Rubyists.

19:00 ~ 19:05 Opening

We'll kick things off by welcoming everyone and giving a short introduction of the event.

19:05 ~ 19:10 OPTiM Lightning Talk

We'll take a moment to hear a quick word from our sponsor.

19:10 〜 19:40 How Reasonable Decisions Created a Security Incident - Paul McMahon

A security incident exposed the resumes of 460 job seekers. The surprising part? There was no single bug or obviously wrong decision to blame. Instead, a series of reasonable technical choices interacted in unexpected ways, creating a vulnerability that went unnoticed until it was too late. In this talk, I’ll share how the incident was discovered, investigated, and resolved, along with practical lessons on security, complexity, and hidden assumptions in Ruby on Rails applications.

Profile

Paul McMahon is the founder of TokyoDev and has been building Ruby on Rails applications for over 20 years. He also founded the Tokyo Rubyist Meetup in 2010, and previously co-founded the event platform Doorkeeper. Today he runs TokyoDev, helping international software developers advance their careers in Japan, while staying hands-on with the development and operation of the site’s Rails application.

19:40 〜 20:00 Rubyist show and tell

Do you have a cool snippet of Ruby code that you'd like to share, but it doesn't warrant an entire presentation? A challenge with your Ruby application you've been struggling with, and would like some advice? A helpful library or tool you've come across? This is your chance to share it.

For those who'd like to participate, you'll have up to five minutes. There's no need to create a slide deck, but you'll be able to use the projector if you have a code sample or something else to share. While we'll ask you if you'd like to participate when signing up, this is just to gauge interest, and you can change your mind on the day of the event.

20:00〜 21:00 Open Networking

Discuss the presentation, how third time's the charm, or anything else Ruby related with the other attendees.

Venue Sponsor

OPTiM Corporation utilizes AI, IoT, cloud, and robotics technologies to realize DX in all industries and provide a sustainable future for all people. Our Mobile Device Management service OPTiM Biz, developing with Ruby on Rails, currently has administrated introduced 180,000 companies. OPTiM Biz is helping IT department introduce corporate DX.

Code of Conduct

Tokyo Rubyist Meetup is a safe and inclusive event. By attending, you agree to our code of conduct.

Photography Policy

Event staff may take photos and videos during the event, mainly of the talks and the overall atmosphere, which may be shared online after the event.

About this community

Tokyo Rubyist Meetup

Tokyo Rubyist Meetup

Tokyo Rubyist Meetup (trbmeetup) is an event that seeks to help bridge the Japan and international ruby and ruby on rails community. It will hold regular meetings where Japanese Rubyists can commun...

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