Yes, e.g. outlook replaces links in mails so they can scan the site first. Also some virusscanners offer nail protection, checking the site that's linked to first, before allowing the mail to end up in the user's mail client.

Thats why you never take actions on a GET request, but require a form with button for the user to do a POST.

[–] TrumpetX 11 points 3 months ago (1 children)

It can be worse, we had to add a captcha for those link scanners cause they'd submit the forms and invalidate tokens too:(

[–] [email protected] 4 points 3 months ago

Wow. That sounds terrible. Good to know.

[–] [email protected] 2 points 3 months ago

e.g. outlook replaces links in mails so they can scan the site first. Also some virusscanners offer nail protection, checking the site that’s linked to first, before allowing the mail to end up in the user’s mail client.

Proofpoint does this too, but AFAIK they all just change the link rather than go to it. The link is checked when the user actually clicks on it. Makes sense to do it on-demand because the contents of the link can change between when the email is received and when the user actually clicks it.