CVE-2023-39044 in Line
Summary
by MITRE • 09/20/2023
An information leak in ajino-Shiretoko Line v13.6.1 allows attackers to obtain the channel access token and send crafted messages.
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Analysis
by VulDB Data Team • 01/22/2026
The vulnerability identified as CVE-2023-39044 represents a critical information disclosure flaw within the ajino-Shiretoko Line messaging application version 13.6.1. This security weakness stems from improper handling of authentication tokens during message transmission processes, creating an avenue for malicious actors to extract sensitive channel access tokens from the application's memory or network communications. The vulnerability specifically affects the LINE messaging platform's implementation and demonstrates a significant lapse in secure token management practices. The flaw allows unauthorized parties to intercept and obtain valid channel access tokens that grant elevated privileges within the messaging ecosystem. This information leak directly compromises the integrity of the authentication mechanism and enables attackers to establish unauthorized communication channels with target applications.
The technical implementation of this vulnerability involves a failure in proper input validation and output sanitization within the application's token handling routines. Attackers can exploit this weakness by crafting specially formatted messages that trigger the application to inadvertently expose channel access tokens through network packet analysis or memory inspection techniques. The vulnerability manifests when the application processes incoming or outgoing messages without adequate protection against token leakage, particularly during authentication flows or when establishing secure communication channels. This flaw aligns with CWE-200, which categorizes information exposure vulnerabilities, and represents a specific instance where sensitive data is unintentionally disclosed through application behavior rather than through direct exploitation of other weaknesses. The vulnerability's impact is amplified by the fact that channel access tokens typically grant access to sensitive communication channels, user data, and application functionalities that should remain protected from unauthorized access.
The operational implications of CVE-2023-39044 extend beyond simple information disclosure, as it enables attackers to perform unauthorized message sending operations within compromised channels. Once an attacker obtains a valid channel access token, they can impersonate legitimate users or applications within the messaging platform, potentially leading to data exfiltration, spamming activities, or more sophisticated social engineering campaigns. This vulnerability creates a persistent threat vector that can be exploited repeatedly, as the extracted tokens may remain valid for extended periods unless actively revoked. The attack surface is particularly concerning given the widespread use of LINE messaging applications in enterprise environments and the potential for these tokens to provide access to confidential business communications and user data. Organizations utilizing ajino-Shiretoko Line v13.6.1 are at risk of unauthorized access to their messaging infrastructure, potentially leading to compliance violations and reputational damage.
Mitigation strategies for this vulnerability should focus on immediate implementation of proper token management practices and enhanced security controls within the messaging application. Organizations must implement robust input validation mechanisms to prevent token leakage during message processing and ensure that authentication tokens are properly sanitized before being exposed to network communications or memory structures. The recommended approach includes deploying secure token rotation mechanisms, implementing strict access controls for channel operations, and establishing monitoring systems to detect unauthorized token usage patterns. Security patches should be applied immediately to upgrade to versions that address the information disclosure vulnerability, while network segmentation and traffic monitoring should be implemented to detect potential exploitation attempts. This vulnerability demonstrates the importance of following security best practices outlined in the OWASP Top Ten and aligns with ATT&CK technique T1566, which covers credential harvesting through various attack vectors including information disclosure. Organizations should also consider implementing zero-trust network principles and regular security assessments to identify similar vulnerabilities in their messaging infrastructure and ensure comprehensive protection against information leakage attacks.