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Comment by avian | Hacker News Reader

I can't replicate this with current Thunderbird 68.11.0 on Debian. It honors parameters such as subject= and body=, but attach= seems to be ignored.

After a quick search through the paper [1] it seems that authors forgot to mention the software versions they were using in their research.

[1] https://www.nds.ruhr-uni-bochum.de/media/nds/veroeffentlichu...

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It seems the thunderbird issue is actually an issue in xdg-open, see: https://bugzilla.mozilla.org/show_bug.cgi?id=1613425 https://gitlab.freedesktop.org/xdg/xdg-utils/-/issues/177

So you are only affected if your system uses xdg-open to parse mailto links.

It should be patched since Dec 2019: https://twitter.com/jensvoid/status/1295633279727673344

I found a discussion from March 2009 which suggests this issue was known back then [1]. Maybe the same feature was re-introduced later in some other part of the code? The link to source repo in the post is dead, but the file it references (nsSmtpUrl.cpp) still contains this comment on line 88 in current version:

/* DO NOT support attachment= in mailto urls. This poses a security fire hole!!!

[1] http://forums.mozillazine.org/viewtopic.php?f=30&t=1172555

That interesting as the OP is using `attachment` as the param when it is/was actually `attach`.

A comment in source code. Not the discerning professional's preferred tool for guaranteeing security-critical behaviors to prevent "fire holes".

What should they do? Static analysis would be nice, but it's probably too complex to adopt in that kind of codebase.

In the end, the only viable option is to forbid this behaviour, and document a rationale so nobody will enable it back again.

Perhaps they could make this warning bigger, but other than that...

They could have added a regression test, no? Give it an example with ?attach= and verify that no attachment is added.

Looking at the linked src code, there’s lots of mixed tabs/spaces for indent. shudders

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