LINE

1. Overview

We detected an incident whereby some messages sent on June 30, 2021 between 12:00pm to 12:12pm JST by LINE Official Account were erroneously displayed in another LINE Official Account room within the LINE app. The cause of the incident was due to an outage caused by a connection setting change on our cache server.

We have since corrected the issue and have unsent these messages. In addition, the affected messages were not sent to anyone other than the recipient user.

We can also confirm that there has not been any leakage of personal information stemming from the incident.

We sincerely apologize to our users and LINE Official Account administrators for any inconvenience this may have caused and will make our best efforts to prevent a reoccurrence of this issue.

The details of our investigation and response to alert our users of this issue are summarized below.

2. Incident assessment

Impact on users:

Message received from LINE Official Account was displayed in another LINE Official Account room

Impact on LINE Official Account administrators:

・Message not sent from a LINE Official Account was displayed in a chat room
・Message sent from a LINE Official Account is displayed in another LINE Official Account that was unintended

Period of occurrence:

June 30, 2021 at 12:00pm to 12:12pm JST

Scope:

(1) The number of users whose messages received from LINE Official Account were displayed in the room of another Official Account

     1,053 users (Breakdown by country: Japan 264 / Thailand 729 / Taiwan 56 / Other 4)

(2)* The number of accounts whereby messages that have not been sent from an LINE Official Account were displayed in a room

     26 accounts

(3)* The number of accounts in which messages sent from a LINE Official Account was not displayed in the room

     63 accounts

*Some cases were detected whereby both (2) and (3) were applicable

Action taken on behalf of users and LINE Official Account administrators:

・The erroneously displayed messages were cancelled
・The erroneously displayed messages were excluded from LINE Official Account charges

3. Cause and prevention of recurrence

Cause:

Outage caused by a connection setting change on our cache server.
(Cache server refers to a server that temporarily stores data to reduce database load.)

Measures to prevent recurrence:

The connection settings to the cache server that caused this incident have been changed. We have also created an in-house guideline for the connection settings to the cache server and have included a description of this incident to prevent a recurrence of this issue.

4. Correspondence in chronological order (all times are JST)

・June 30, 2021 at 12:00: An outage occurred when changing connection settings to the cache server
・June 30, 2021 at 12:05: We received a report that there was a message transmission error on some LINE Official Accounts and launched an investigation
・June 30, 2021 at 12:12: The cache server was restarted and it was confirmed that the sending error was resolved
・June 30, 2021 at 14:16: During the investigation, it was discovered that messages sent from LINE Official Accounts were found to be erroneously displayed in separate unintended LINE Official Account rooms
・June 30, 2021 at 16:00-19:00: Erroneously displayed messages were identified and canceled
・June 30, 2021 at 19:15: As a primary response measure, a program was applied that would detect as an error in the event a similar failure occurred in the future
・July 1, 2021 at 18:52: Confirmed reproduction of the incident in an internal setting
・July 1, 2021 at 21:56: Incident report was posted on LINE Developers News page (https://developers.line.biz/ja/news/2021/07/01/messaging-api-outage/)
・July 2, 2021 at 15:11: Cause of the incident was discovered to be an outage caused by a connection setting change on our cache server that occurred on June 29, therefore the settings were changed
・July 5, 2021: Individual notifications were sent to affected LINE Official Account administrators
・July 6-9, 2021: Individual notifications were sent to affected LINE users
・August 11, 2021: Notification posted on the LINE Security & Privacy website

5. Update history

August 11, 2021: Notification posted

6. Inquiries regarding this matter

For inquiries regarding this matter, please contact us at the below link:

https://contact-cc.line.me/detailId/12697