bug#58171: 29.0.50; Change gnus-user-agent to nil by default

bug#58171: 29.0.50; Change gnus-user-agent to nil by default

[Stefan Kangas]

Severity: wishlist

This is a proposal to set `gnus-user-agent' to non-nil by default.

To save some typing, I'll just quote what Daniel Kahn Gillmor said when
they made this change in notmuch back in 2016:

> The User-Agent: header can be fun and interesting, but it also leaks
> quite a bit of information about the user and their software stack.
>
> This represents a potential security risk (attackers can target the
> particular stack) and also an anonymity risk (a user trying to
> preserve their anonymity by sending mail from a non-associated account
> might reveal quite a lot of information if their choice of mail user
> agent is exposed).
>
> It makes sense to have safer defaults.

https://notmuchmail.org/pipermail/notmuch/2016/022789.html

bug#58171: 29.0.50; Change gnus-user-agent to nil by default

[Stefan Kangas]

Stefan Kangas <stefankangas@gmail.com> writes:

> This is a proposal to set `gnus-user-agent' to non-nil by default.
                                                 ^^^^^^^

Should be "nil", of course, as in the subject.

bug#58171: 29.0.50; Change gnus-user-agent to nil by default

[Lars Ingebrigtsen]

Stefan Kangas <stefankangas@gmail.com> writes:

> To save some typing, I'll just quote what Daniel Kahn Gillmor said when
> they made this change in notmuch back in 2016:
>
>> The User-Agent: header can be fun and interesting, but it also leaks
>> quite a bit of information about the user and their software stack.
>>
>> This represents a potential security risk (attackers can target the
>> particular stack) and also an anonymity risk (a user trying to
>> preserve their anonymity by sending mail from a non-associated account
>> might reveal quite a lot of information if their choice of mail user
>> agent is exposed).
>>
>> It makes sense to have safer defaults.

I think in the case of Gnus, defaulting this header to nil would just be
security theatre -- there so many distinctive features in how
Gnus/Message formats messages that anybody can tell that it's from Emacs
even without that header.

So I don't think it makes sense to do this, and I'm closing this bug
report.

bug#58171: 29.0.50; Change gnus-user-agent to nil by default

[Stefan Kangas]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> I think in the case of Gnus, defaulting this header to nil would just be
> security theatre -- there so many distinctive features in how
> Gnus/Message formats messages that anybody can tell that it's from Emacs
> even without that header.

For me, the greater concern is anonymity/privacy, where I do think
it's better to be less specific.

How about removing just the Emacs version?  If you announce "29.0.50",
only very few people will be running that version at any given time,
certainly fewer than is running the releases.

bug#58171: 29.0.50; Change gnus-user-agent to nil by default

[Lars Ingebrigtsen]

Stefan Kangas <stefankangas@gmail.com> writes:

> How about removing just the Emacs version?  If you announce "29.0.50",
> only very few people will be running that version at any given time,
> certainly fewer than is running the releases.

That's a good point.  I've now removed the `type' and `emacs' from the
default value.