Task #104329: Do not use no-reply@example.com email addres as a fallback for the defaultMailFromAddress - TYPO3 Core - TYPO3 Forge

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Task #104329

open

Do not use no-reply@example.com email addres as a fallback for the defaultMailFromAddress

Added by Marcin Sągol 5 months ago. Updated about 1 month ago.

Status:

New

Priority:

Could have

Assignee:

Category:

Backend API

Target version:

Candidate for Major Version

Start date:

2024-07-07

Due date:

% Done:

Estimated time:

TYPO3 Version:

PHP Version:

8.3

Tags:

mail, mailer, mailng, configuration, backend

Complexity:

easy

Sprint Focus:

Description

The typo3/cms-core/Classes/Utility/MailUtility.php class offers helper methods to fetch several configuration values related to making, providing also some fallbacks.

One of them is this method:

public static function getSystemFromAddress(): string
{
    $address = $GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromAddress'] ?? null;

    if (!is_string($address) || !GeneralUtility::validEmail($address)) {
        // still nothing, get host name from server
        $address = 'no-reply@' . php_uname('n');
        if (!GeneralUtility::validEmail($address)) {
            // if everything fails use a dummy address
            $address = 'no-reply@example.com';
        }
    }
    return $address;
}

So, here as a very last fallback we have the no-reply@example.com used which might not be a good idea as it can expose some sensitive data.
It should be considered if this fallback should be used and even if the php_uname usage is intended.
$GLOBALS['TYPO3_CONF_VARS']['MAIL']['defaultMailFromAddress'], just throw some exception.

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Updated by Friedemann Altrock 5 months ago

Hi,

can you specify what sensitive data would be exposed and how?

FTR:
example.com is reserved as per RFC2606: https://www.rfc-editor.org/rfc/rfc2606.html
As long as IANA (Internet Assigned Numbers Authority) does not start an SMTP server on that domain, we'll be good.

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Updated by Garvin Hicking 5 months ago

Description updated (diff)

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Updated by Garvin Hicking 5 months ago

$0.02: While IMO technically valid, mails with that sender shouldn't be sent from production sites, also because nowadays with "wrong" senders like that mails won't be delivered (spam; unless a mail relay rewrites the senders). How about gating this so both fallbacks only work for non-production environments?

Those installs which use mail relays on production that rewrite senders, they should manually set "no-reply@example.com". I think throwing an exception then is good.

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