CVE-2023-0616 - Thunderbird Denial of Service Attack via MIME Email Exploitation

In recent times, a new vulnerability has been identified in Thunderbird, the popular open-source email client. This vulnerability, known as CVE-2023-0616, can potentially be exploited by attackers to perform a Denial of Service (DoS) attack on the victim's machine. If a MIME email combines both OpenPGP and OpenPGP MIME data, an attacker can take advantage of this vulnerability to cause Thunderbird to lock up and become unresponsive.

This article will delve into the details of this vulnerability and provide the original references for further understanding. Additionally, we will discuss potential exploits in simple language to help you grasp the severity of this issue.

Details of CVE-2023-0616

First, let us look into the cause of this vulnerability. The issue arises when a MIME email message combines both OpenPGP and OpenPGP MIME data in a specific manner. Under these circumstances, Thunderbird may attempt to process and display the message repeatedly, ultimately leading to its user interface becoming locked and unresponsive.

To put it simply, an attacker could craft this kind of message using the OpenPGP and OpenPGP MIME data structures and send it to a targeted victim. Should the recipient open this email in Thunderbird, the result could be a locked and unresponsive email client – a classic DoS attack.

An example of a message with this particular structure is outlined below

MIME-Version: 1.
Content-Type: multipart/mixed; boundary="----=_Part_001_"
From: attacker@example.com
To: victim@example.com
Subject: CVE-2023-0616 PoC

------=_Part_001_
Content-Type: text/plain

This is a CVE-2023-0616 PoC message attempting a DoS attack.

------=_Part_001_
Content-Type: multipart/encrypted; boundary="----=_Part_002_"; protocol="application/pgp-encrypted"

------=_Part_002_
Content-Type: text/plain

This is the part containing OpenPGP and OpenPGP MIME data.
------=_Part_002_--
------=_Part_001_--

Affected Thunderbird Versions

The vulnerability affects all versions of Thunderbird earlier than 102.8. If you are using a version of Thunderbird older than 102.8, it is crucial that you update your software to avoid this potential attack.

You can find more information on this vulnerability from these primary sources

1. CVE-2023-0616 - Official listing in the Common Vulnerabilities and Exposures database.
2. Mozilla Security Advisories - Official security advisory from Mozilla, the organization behind Thunderbird. Here you can find details about the vulnerability and how to fix it.

In order to mitigate this vulnerability, users should do the following

1. Update to the latest version of Thunderbird (currently 102.8). If your version is earlier, you can download the latest version from the official Thunderbird website.
2. Exercise caution when opening email messages from unknown senders, especially if they contain attachments.

Conclusion

CVE-2023-0616 is a significant vulnerability that can lead to a DoS attack. Attackers can craft malicious MIME emails containing specific OpenPGP and OpenPGP MIME data structures that, when opened in vulnerable Thunderbird clients, cause the application to lock up and become unresponsive. To protect yourself from this potential attack, be sure to update your Thunderbird client to the latest version and stay vigilant when opening emails from unknown sources.

Timeline

Published on: 06/02/2023 17:15:00 UTC
Last modified on: 06/08/2023 19:35:00 UTC