https://www.adobe.com/acrobat/resources/can-pdfs-contain-viruses.html

Minimizing risk is important. Even clicking on a link such as the one above is risky.

(Some of the letters could be in Cyrillic. So I take the extra effort to type out the link. I find unusually long links suspicious. Also, you can use a trusted search engine to find out if you can reach the same web page.) To any developers out there: PDF file readers should have malware detection software built in that warns a user about potential malware. Such as PDF’s built by latex that have write18 enabled.