CVE-2022-41568 in LINE
Summary
by MITRE • 11/29/2022
LINE client for iOS before 12.17.0 might be crashed by sharing an invalid shared key of e2ee in group chat.
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Analysis
by VulDB Data Team • 04/26/2025
The vulnerability identified as CVE-2022-41568 represents a critical stability issue within the LINE client for iOS platforms prior to version 12.17.0. This flaw specifically manifests when users attempt to share an invalid end-to-end encryption shared key within group chat environments, leading to unexpected application crashes. The vulnerability stems from inadequate input validation mechanisms within the client's encryption key handling subsystem, which fails to properly sanitize or reject malformed shared keys before processing them within the group chat context.
The technical implementation of this vulnerability involves the client's failure to validate the integrity and format of shared encryption keys during the group chat key exchange process. When an invalid shared key is transmitted or received, the application's memory management routines encounter unexpected data structures that trigger abnormal termination sequences. This represents a classic buffer overflow or memory corruption scenario where the application attempts to process malformed cryptographic data without proper defensive programming measures. The vulnerability falls under the category of improper input validation as classified by CWE-20, specifically manifesting as CWE-20 in the context of cryptographic key handling within secure communication protocols.
From an operational perspective, this vulnerability creates significant risks for LINE's end-to-end encryption service reliability within group chat environments. Attackers could potentially exploit this weakness to disrupt group communications by intentionally sharing malformed keys, causing multiple participants to experience application crashes simultaneously. The impact extends beyond simple service disruption to potentially undermining user trust in the security guarantees provided by LINE's encryption features. The vulnerability affects the availability aspect of the CIA triad, as it can be leveraged to create denial-of-service conditions within group chat conversations where encryption is actively being used.
The exploitation of this vulnerability requires minimal technical expertise and can be achieved through simple manipulation of shared key parameters within the group chat context. This makes it particularly dangerous as it can be exploited by both malicious actors seeking to disrupt services and potentially by threat actors looking to gain insights into the client's internal error handling mechanisms. The vulnerability's impact is amplified in environments where group chats utilize end-to-end encryption, as the attack vector specifically targets the encryption key management infrastructure that users rely upon for secure communications. Security practitioners should note this vulnerability's alignment with ATT&CK technique T1499.004 related to network disruption attacks through application instability, and its potential for being leveraged as part of broader attack chains targeting communication platform availability.
Mitigation strategies should focus on implementing comprehensive input validation for all shared key parameters within the encryption key exchange process. The recommended approach includes adding robust sanitization routines that validate key format, length, and cryptographic integrity before processing. Additionally, implementing proper exception handling and graceful degradation mechanisms can prevent application crashes when malformed keys are encountered. Users should be encouraged to upgrade to LINE client version 12.17.0 or later, which includes patches addressing this vulnerability through improved key validation routines. Organizations utilizing LINE for business communications should consider implementing monitoring solutions to detect unusual patterns of client instability that might indicate exploitation attempts. The fix should also incorporate defensive programming practices that isolate cryptographic operations from core application processes to prevent cascading failures when invalid keys are processed, ensuring that the overall platform stability remains intact even when individual encryption operations fail.