Block tracking images from loading
Categories
(Thunderbird :: Security, enhancement)
Tracking
(Not tracked)
People
(Reporter: u187t568z, Unassigned)
Details
(Keywords: dupeme)
User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:87.0) Gecko/20100101 Firefox/87.0
Steps to reproduce:
Loaded email that loads tracking pixels in a HTML email in Thunderbird 86.0b3
Build ID: 20210212193837
OS: Linux 5.10.16-arch1-1 #1 SMP PREEMPT Sat, 13 Feb 2021 20:50:18 +0000
Actual results:
Images loaded letting trackers get my information.
Expected results:
It will be nice if there was a toggle in Thunderbird that blocks known trackers and tracking images from loading in the email reader pane. A good start is to simply use an existing list of trackers and block all of them. A freely licensed list is available here: https://github.com/disconnectme/disconnect-tracking-protection
This option can be offered with a toggle for enabling and disabling it.
It must be ON by default and a small button may be placed in the Thunderbird window (next to reply, forward and delete buttons) to switch it off if it breaks email formatting. Switching it off should be followed after warning user about tracking pixels and tracking images and getting confirmation.
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Comment 1•5 years ago
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"Edit > Preferences > Advanced > Privacy > Block loading of remote images" already exists?
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Comment 2•5 years ago
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And blocking (all) is actually on by default.
(In reply to Andre Klapper from comment #1)
"Edit > Preferences > Advanced > Privacy > Block loading of remote images" already exists?
(In reply to Magnus Melin [:mkmelin] from comment #2)
And blocking (all) is actually on by default.
And that is good. But not enough in my opinion.
CONTEXT:
Thunderbird can of course block all images from loading including non-tracking (benign) images that are used for design purposes in an HTML formatted email. Tracking pixels or Tracking images or Web Beacons as Wikipedia calls it are usually some javascript code and/or associated images (usually 1px wide and 1px high) that are used to gather information about the recipient of the email. These are different from design elements in the page that they are usually not visible. Their sole purpose is to track user activity.
Thunderbird can effectively prevent this tracking by simply blocking all images - although it is ineffective in beating tracking elements by itself. When the user opts to load the images, the user also unwittingly opts to load tracking pixels. What I'm requesting in this bug report is a second layer of defense. At the simplest level, this can be based on a blacklist that's maintained by reputable security software.
Such lists are available under libre licenses. One such list (of known phishing sites) is here: https://github.com/MailScanner/v5/blob/master/common/etc/MailScanner/phishing.bad.sites.conf
Another list of possible trackers is here: https://github.com/disconnectme/disconnect-tracking-protection
BEHAVIOUR:
- Thunderbird would by-default block all images.
- User clicks button to show all images in the email
- Thunderbird displays safe images, but blocks all tracking images / tracking pixels
3a. Thunderbird also displays a small warning that says it has blocked tracking elements - User can opt (at their own risk) to enable tracking elements per-email by clicking a button
4a. User is shown a warning modal asking for confirmation to rule-out accidental clicks - If user confirms, tracking images are loaded
Internally, Thunderbird simply uses a list of trackers that it scans for in each email and blocks them from loading, or even replaces them with dummy image links - like the stereotypical spy-in-a-trench-coat icon - with low contrast ratio so as to not ruin the design of the email.
WHY SHOULD THUNDERBIRD IMPLEMENT THIS?
Because this basic protection ought to be an in-built feature. Of course I can possibly plug in a malware scanner to TB or use an extension that does this. But TB has an obligation to include this feature as default. Not many people know what tracking-pixels are or their risks, but they deserve the protection anyway. All said and done, there are no extensions that can reliably protect from trackers in the AMO portal.
Implementing this will also make the protections extensible to other kinds of email security like protection from spam, phishing, etc. which is always a good thing to have.
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Comment 4•5 years ago
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Of course there are no extensions that can reliably protect from trackers in the AMO portal.
Thunderbird extensions are hosted on https://addons.thunderbird.net/en-US/thunderbird/ aka the ATN portal.
You probably won't find one there either.
Adding recent article (basically an advertisement for Hey, but whatever) about tracking pixels: https://www.bbc.com/news/technology-56071437
News pieces like these will definitely keep coming and that's a good thing because people become more aware of these. I think Thunderbird has a strong role to play in protecting users from these threats. If this feature is available - even in limited capacity - it will boost adoption and confidence in Thunderbird.
Coincidentally, Adguard made and released another list of trackers - this time CNAME cloaked trackers.
Blog post: https://adguard.com/en/blog/cname-tracking.html
Tracker list (MIT Licensed): https://github.com/AdguardTeam/cname-trackers
At the moment, I realize I can simply add Adguard DNS to network.trr.resolvers list via Config Editor for some basic protection. But that alone will not help since it's not easy for everyone to configure. I think along with DNS over HTTPS (TRR), having the ability to block trackers will really help.
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