Vulnerability identifier: #VU28569

Vulnerability risk: Medium

CVSSv3.1: 4.8 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:P/RL:O/RC:C]

CVE-ID: CVE-2020-12398

CWE-ID: CWE-319

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Mozilla Thunderbird
Client/Desktop applications / Messaging software

Vendor: Mozilla

Description

The vulnerability allows a remote attacker to gain access to sensitive information.

The vulnerability exists in STARTTLS implementation for an IMAP, when the server sends  a PREAUTH response. In this case Thunderbird will continue with an unencrypted connection, causing email data to be sent without protection.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Mozilla Thunderbird: 68.0 - 68.8.1, 60.0 - 60.9.1

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External links
http://www.mozilla.org/en-US/security/advisories/mfsa2020-22/
http://bugzilla.mozilla.org/show_bug.cgi?id=1613623

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, proof of concept for this vulnerability is available.