Dangerzone, a new open source tool that First Look Media just released at the Nullcon 2020 hacker conference in Goa, India, aims to solve this problem. You can install dangerzone on your Mac, Windows, or Linux computer, and then use it to open a variety of types of documents: PDFs, Microsoft Office or LibreOffice documents, or images. Even if the original document is dangerous and would normally hack your computer, dangerzone will convert it into a safe PDF that you can open and read.

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When dangerzone starts containers, it disables networking, and the only file it mounts is the suspicious document itself. So if a malicious document hacks the container, it doesn’t have access to your data and it can’t use the internet, so there’s not much it could do.

Pdftk allows you to manipulate PDF easily and freely. It does not require Acrobat, and it runs on Windows, Linux, Mac OS X, FreeBSD and Solaris.

HTMLDOC converts Hyper-Text Markup Language ("HTML") files and web pages into indexed HTML, Adobe® PostScript®, or Adobe Portable Document Format ("PDF") files. HTMLDOC is available in both commercial and open source versions.