CVE-2021-30496 Explained : Impact and Mitigation

This article provides detailed information about CVE-2021-30496, a denial of service vulnerability in the Telegram app 7.6.2 for iOS that allows remote authenticated users to crash the application by pasting a specific message into a channel or group.

Understanding CVE-2021-30496

This section covers the key details about the vulnerability.

What is CVE-2021-30496?

The Telegram app 7.6.2 for iOS is affected by a vulnerability that enables remote authenticated users to trigger a denial of service attack by inserting a specially crafted message, causing the application to crash.

The Impact of CVE-2021-30496

Although the vendor has disputed this behavior as a vulnerability, the ability for authenticated users to crash the app by sending a specific message can disrupt user experience and potentially lead to misuse of the application.

Technical Details of CVE-2021-30496

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability lies in the MtProtoKitFramework of the Telegram app 7.6.2 for iOS, allowing attackers to cause a denial of service by sending a specific message, especially in the Persian language.

Affected Systems and Versions

The issue affects version 7.6.2 of the Telegram app for iOS. All users on this version are vulnerable to the denial of service attack.

Exploitation Mechanism

Remote authenticated users can exploit the vulnerability by pasting the attacker-supplied message, triggering a crash in the application's MtProtoKitFramework.

Mitigation and Prevention

This section provides insights on how to address the CVE-2021-30496 vulnerability.

Immediate Steps to Take

Users are advised to exercise caution when receiving messages, especially from unknown or untrusted sources, to prevent the application from crashing.

Long-Term Security Practices

To enhance security, users should regularly update their Telegram app to the latest version and be cautious while interacting with messages from unfamiliar sources.

Patching and Updates

Developers should address this vulnerability in upcoming updates to ensure the stability and security of the Telegram app for iOS.