【Team & Project】 Introducing LINE’s Infrastructure Security Experts

LINE’s software engineers belong in development centers comprised of different departments running various projects. The Team & Project series takes a closer look at these departments and projects, their roles, team structure, tech stacks, challenges that lie ahead, roadmaps, and more. In this blog post, we interviewed members of the Infra Protection Team who keep LINE’s infrastructure safe.

Jihoon Lee, Seungnam Jun, Wontae Choi, and Simon Vestin told us their stories.

Infra Protection Team in a Zoom meeting

–– What do you do at LINE?

Jihoon: I am a member of the Infrastructure Security division, a subset of LINE’s Security Center. As a team manager and security architect, I’m responsible for the general management of projects and tasks that involve multiple teams.

Seungnam: After joining LINE as a security engineer, I have been placed in the Infra Protection Team to work on cloud service security and VDI migration.

Wontae: I am a team manager overseeing LINE’s network security-related projects. My top priorities as manager is to ensure my team’s job satisfaction, help my team members improve their skills, and increase LINE’s network security level.

Simon: I am a security engineer working on network security. Currently, my main tasks include configuring devices that we operate, automating our servers’ security checks, and analyzing security-related data that has been collected.

― What led you to LINE?

Jihoon: Before joining LINE, I was working in Korea. I discovered LINE in 2014 when a colleague left my company to work for LINE. Out of curiosity, I attended LINE DEVELOPER DAY the following year. I remember wanting to work at LINE as I listened to the tech talks and learned more about the company. I eventually joined LINE in June 2016 through a referral by the aforementioned colleague.

Switching jobs wasn’t easy though. Working at LINE meant having to move to Japan, which meant a drastic life transition for my wife and son too. Because my job change required my family’s support, I really talked it through with my wife. Joining LINE was a major challenge for many reasons, one being that I wasn’t very fluent in Japanese at the time, but in hindsight, I’m glad I took a leap of faith.

Seungnam: I’ve always wondered about living in Japan. When I learned about LINE, the idea of running different security solutions and projects fascinated me. Then, I found out that efficiency is a very important part of their work culture, and engineers are free to decide how they want to work so that they can take advantage of every opportunity to improve their skills. That was all I needed to hear to join LINE from December 2016.

Wontae: Before LINE, I was working for a security vendor in Korea, helping foreign companies with their network security. Managing internal and external networks, my ambition to take part in more diverse security projects grew. I had also wanted to work in a foreign country if I had the chance.

That was when a former colleague from my previous job invited me to come and work at LINE, and I took the first step toward fulfilling my dreams by joining in July 2016. As with Jihoon, I couldn’t speak a word of Japanese at the time. So, as soon as I found out that I got the job, I had one week to learn the Japanese alphabet in hiragana and katakana before moving to Japan. That was an intense week (laughter).

Simon: I’ve always been interested in Japan, but I was concerned whether the work culture would suit me. As for LINE, I had already been using the app to communicate with my Japanese friends back when I was still living in Sweden. I joined LINE as a new graduate by coincidence. I was invited to take part in my university’s exchange program, and happened to take LINE’s coding test in Kyoto for an engineering position during my trip. I joined LINE because people from many countries work here, the organization is flat and casual, and the work environment is global and multicultural.

Clockwise from top left: Jihoon Lee, Seungnam Jun, Simon Vestin, and Wontae Choi

–– What do you find rewarding in your work?

Jihoon: There are three things I appreciate about my current job –– getting to be involved in highly specialized development projects all the time, the engineer-centric work culture, and getting to work among competent, global talents.

Because LINE is running so many different services on its messaging platform, I feel that I am getting a level of experience that one would normally need to work at numerous companies to gain. Furthermore, LINE’s engineering force is built upon a culture that values its people, and this principle is reflected in the Security Center as well. In that sense, I think engineers are being fairly evaluated in this company overall.

It’s also exciting to work with people from many different places –– Japan, Korea, China, Taiwan, Sweden –– and have meetings in multiple languages. Finally, I feel that working among talented people creates positive peer pressure for everyone to improve their skills.

Wontae: Seeing yourself grow is a rewarding experience. LINE’s work environment allows us to improve not only our programming skills but also learn different languages as part of work. Most engineers are bilingual. Some are even multilingual. I couldn’t speak any Japanese when I first came to Japan, but I’ve also become a fluent Japanese speaker since.

Seungnam: As a cloud service security and VDI migration engineer, the most rewarding moment for me is seeing a new service released after a bunch of us had worked together to maximize its safety.

Fixing problems and stabilizing systems while running security solutions in parallel is another satisfying part of my job.

Wontae: In order to keep LINE’s network secure in a fast-changing internet environment, we have to keep up on the latest security trends. This is fun, and leads to personal growth too. Because LINE has data centers and offices in multiple locations in and outside of Japan, we get to experience a wide variety of network environments –– something you can only experience in a global company.

Simon: I appreciate my job for several reasons. First, similar to the reason why I joined LINE, I appreciate the fact that the culture here respects everyone’s opinion regardless of seniority, and anyone can start a project as long as they have a good idea. Second, a major motivator for me is knowing that I am an important contributor to a finished product. Third, LINE’s infrastructure allows new projects to start quickly. Using our proprietary cloud platform, we can shape our ideas almost as quickly as they come to mind. Tackling problems one after another in a fast-paced environment is very exciting.

Lastly, as my colleagues also mentioned, LINE’s work environment is a mix of all sorts of cultures and languages, so each person brings a different perspective to the table. I am grateful to be working in such a multicultural group of talents.

–– What is your team’s structure and role?

Jihoon: Here is the organizational structure.

The Infra Protection Team 1 mainly handles system security.

This team has 10 core members including myself. Eight of us are working in Japan, and the other two are based in Korea.

Our mission is to provide safer Infrastructure for LINE users and LINERs.

Roughly speaking, there are two types of infrastructure. The first is infrastructure necessary to operate LINE’s global services. The second includes computers and other systems used for work. The Infra Protection Team 1 is responsible for LINE’s service infrastructure.

Tasks include:

  • Analyzing security problems that are found in LINE’s infrastructure
  • Finding technical solutions to problems

Temporarily implementing third-party products and test the reliability of that product’s safeguards as part of the process to consider applying the products to LINE’s infrastructure

Infrastructure scope and risk model

Wontae: The Infra Protection Team 2 mainly handles network security. This team has six core members including myself. Members are working from different locations. One member works at LINE Fukuoka while others work in Korea. There are also three outsourced engineers on the team in charge of operation.

Our mission is to provide security solutions for the LINE Group’s service and office networks.

To put it another way, “We work to provide safer infrastructure for LINE’s users and LINE engineers.”

Tasks include: Designing networks for new services and office spaces, and defining their security solutions

Maintaining and improving the network security of existing services and offices

We are currently running a number of large-scale projects, including launching a new Fintech service, renewing our Korean office’s network, and building a zero trust environment.

–– Please tell us about your team members.

Jihoon: My team members are diverse. To give you an idea, some have a degree in Computer Science, some have a programming background, some used to work as security consultants specialized in cyber security, some members’ former job involved detecting unknown malware, and some used to design, build, and operate security platforms for gaming companies and other large-scale entities.

Because our main job is to build security solutions for large-scale infrastructure, we must be able to resolve technical problems based on a thorough understanding of computing, software, and security. Did I mention we even have a medical doctor on our team?

Jihoon talking about his team

Wontae: As you would expect from a team in charge of network security, many of our members have a very deep understanding of networks on top of a thorough knowledge on security. Furthermore, we each have our own added strength, such as strong programming skills, documentation skills, specialized knowledge on network equipment and protocols, and language skills. Although everyone is young (the average age being below thirty), everyone is very technically capable.

–– What kind of technologies and development environments are you using?

Jihoon: Again, our mission is to provide LINE and its stakeholders with the most secure infrastructure. This includes infrastructure necessary to operate LINE’s global services, and LINE employees’ computers and other systems for work.

As part of our job, we identify risks in LINE’s current and planned service infrastructure, and lead projects to improve our security solutions. Below are some examples.

  • Risk Assessment & Management
  • Service Infrastructure Safeguard DevOps
  • Security Management

When you hear infrastructure security, I think most people imagine outsourcing the development and operation to a consulting firm or system integrator. At LINE, we use a host OS, and internalize the full process to manage infrastructure, including research, design, development, and operation. Because we built our own infrastructure from scratch, we are able to adjust to sudden changes in LINE’s service environment, and find flexible ways to fix issues in the infrastructure.

Vulnerability inventory (using CVE, CVSS, CPE (Common Platform Enumeration))

Wontae: Our main job is to automate tasks, analyze logs, and develop tools using Python or other programming languages.

Other tasks include site reliability engineering (SRE) for operational improvement of our service infrastructure, designing network protocols and secure networks, and controlling access with firewalls, VPN, and other solutions.

  • Risk Assessment & Management
  • Service Infrastructure Safeguard DevOps
  • Security Management
Wontae explaining the technologies and development environments his team uses

― What are your team’s current challenges, and how do you plan to overcome them?

Seungnam: Below are the Infra Protection Team 1’s current system security-related challenges.

  • Increasing access restrictions of service infrastructure users
  • Enhancing security against unknown malware and when using cloud services
  • Providing security infrastructure to our overseas banking businesses and other new services
  • Protecting private and public cloud infrastructure

Up to now, the Infra Protection Teams have been tackling a wide range of security problems and implementing solutions to improve LINE’s security together. Now, each team is focusing on resolving issues and improving the sophistication of its own security field for greater work efficiency. After deliberating on cloud services numerous times, we are glad to be providing a safe cloud environment. However, the number of available services is still limited. Our next step is to reinforce the infrastructure so that developers and operators can freely and safely use a wider range of cloud services.

 Design of LINE’s defendable hybrid cloud architecture and how it was implemented from scratch

Here are some of the ways we are strengthening cloud service security.

  • Increase security access for Windows, Linux, and other OSs with point server (gateway) access restriction and a monitoring environment
  • Prepare sandbox-based anti-malware to detect and visualize unknown malware
  • Design and deliver security infrastructure to our overseas banking businesses

Currently, one of the biggest challenges for us is to strike a balance between improving and increasing the sophistication of LINE’s security level, and providing security-related support for upcoming projects that tend to be prioritized over discussions on the former. This year, my team members and I are committed to make progress in this area once and for all. We are working with other IT teams to achieve this goal.

As part of our efforts to expand cloud services, we are holding weekly workshops with others dealing with cloud service providers and infrastructure, and researching together on ways to increase cloud service security. There are about 20 participants every time.

Seungnam talking about his team’s challenges

Simon: The Infra Protection Team 2 is currently faced with the following network security-related challenges.

  • Automating network security settings
  • Enabling secure remote access to LINE’s internal network in times of crisis
  • Visualizing the status of network devices and other equipment to identify server access paths for internal and external network attacks

As a first step, we have developed a system that automatically configures network security settings, and using requested controlled network path data to automatically configure security devices.

Furthermore, to prevent a single point of failure, our network has application-based VPN with zero trust architecture in addition to the conventional SSL VPN so that employees can safely access LINE’s internal network from home even if a natural disaster hits.

We plan to continue developing systems that extract and analyze network device settings before visualization so that public servers can identify them too.

Zero trust environment architecture

― What is your team’s future roadmap?

Seungnam: A major goal is to prepare a manual on cloud service safety so that developers and operators can freely and safely use cloud services. Based on the assumption that no environment is perfectly safe, we must apply correct authentication and encryption processes to all systems, regardless of whether they are internal or external. Our ultimate goal is to make all work environments safe based on zero trust design principles.

Simon: In my team, we will improve LINE’s network environment in the following ways to build a zero-trust network that analyzes and visualizes a wide range of settings so that both developers and operators can easily check network and server security statuses.

  • Improve dynamic access control based on the status of devices used to access LINE’s network
  • Build an environment that enables individualized access control for internal and external networks
Simon talking about his team’s roadmap

― Lastly, please give a message to readers interested in joining your team.

Jihoon: Please join my team if you’re interested in tackling various security issues in complicated large-scale infrastructure.

Seungnam: We are looking for people who are passionate about cloud security, and have new security solution ideas.

Wontae: My team still has network security issues to resolve for k8s and other platforms as well as a zero trust environment. We are looking for enthusiastic engineers willing to take on the challenge with us.

Simon: If enhancing network security for LINE users and building a zero trust environment using the latest technologies sound exciting to you, please join my team!

― The Infra Protection Team is hiring!

Infrastructure Security Engineer / Security Center / Service Infrastructure