Cybersecurity is a top concern as technology continues to evolve, and keeping up with the latest vulnerabilities is crucial. Today, we will discuss an issue affecting the LINE client for iOS before 12.17.. This vulnerability, identified as CVE-2022-41568, could potentially allow an attacker to crash the app by sharing an invalid shared key for end-to-end encryption (E2EE) in group chat. In this article, we will delve into the exploit details, present sample code snippets, and provide links to original references to help you understand and address this problem.

The Vulnerability: CVE-2022-41568
The LINE client for iOS devices running a version earlier than 12.17. might be susceptible to a denial-of-service (DoS) attack. This vulnerability stems from the improper handling of invalid shared keys during the end-to-end encryption process in group chat sessions. In essence, an attacker could crash the LINE application for all group chat participants by sharing an invalid shared key.

Exploit Details

For a threat actor to exploit this vulnerability, they would first need to join a group chat in the LINE app. Then, by using either a custom client or a modified version of the official LINE application, the attacker could manipulate the E2EE implementation to share an invalid shared key in the group chat.

Here's a sample code snippet that demonstrates the process, assuming a successful authentication and connection to the LINE servers:

import line_client

# Assuming successful authentication and connection with LINE server
line = line_client.LineClient(authToken='your_auth_token')

# Join a group chat with its ID
group_id = 'your_group_id'
group = line.getGroupById(group_id)

# Craft invalid shared key
invalid_shared_key = b'\x01' * 32  # 32 bytes of invalid data

# Share the invalid shared key in the group chat

When the invalid shared key reaches the participant devices running LINE client for iOS before 12.17., the app will not be able to handle it correctly, causing it to crash and resulting in a denial of service for the impacted users.


To protect yourself from this vulnerability, upgrade your LINE client for iOS to version 12.17. or later. The developers have addressed the issue, and updating your app will prevent attackers from exploiting this particular flaw.

For more details about CVE-2022-41568 and the official security advisory, refer to these resources

1. LINE Security Advisory
2. National Vulnerability Database (NIST)
3. CVE Details


Staying informed about the latest security vulnerabilities is essential for protecting your digital devices and data. In the case of CVE-2022-41568, users must upgrade their LINE client for iOS to the latest version to mitigate the risk of denial-of-service attacks in group chats. By keeping your apps up-to-date and following cybersecurity best practices, you can reduce your exposure to potentially harmful exploits.


Published on: 11/29/2022 05:15:00 UTC
Last modified on: 12/02/2022 15:38:00 UTC