Voting Blogs: Safely opening PDFs received by e-mail (or fax?!) | Andrew Appel/Freedom to Tinker
Many election administrators in U.S. states and counties need to receive and open PDF files from voters. Some of these administrators receive these PDFs as e-mail attachments. These may be filled-out voter registration forms, or even voted ballots from UOCAVA (overseas and military) voters. We all know that malware can lurk in e-mail attachments; how can those election officials protect themselves from being hacked? Internet return of voted ballots is inherently insecure; that’s a separate issue and I’ll discuss it below. For now, how can one safely open a PDF attachment? I discussed this question with Dan Guido, cybersecurity consultant and CEO of trailofbits.com. The safe way to view a PDF is inside the Chrome or Firefox browser. Printing a PDF directly from Chrome (or Firefox) to your printer is reasonably safe. The unsafe way to view a PDF is with your favorite PDF-viewer app such as Adobe Reader. The reason is simple: Google (for Chrome) and Mozilla (for Firefox) have put enormous effort into making their PDF viewers safe, putting them inside a “sandbox” that the hackers can’t get out of — and they’ve largely succeeded.