Dangerzone: Secure PDFs, Office documents or images

Dangerzone for Linux, Mac or Windows. Finally being able to open PDFs, Office documents and images from unsafe sources with a clear conscience.

With Dangerzone we can finally open PDFs, Office documents or even images from unsafe sources with a clear conscience. Developed by Micah Lee at First Look Media, Dangerzone is now a project of the Freedom of the Press Foundation.

Nearly anywhere are there more dangers lurking than in PDFs or Office documents. Because of course, one cannot (and should) not always go to the source 100 % trust. Dangerzone works on Linux, Mac and Windows machines and is modeled after the popular Qubes OS.

Micah Lee: Inspired by Qubes TrustedPDF

Before we look together how to install Dangerzone, it’s important to understand how it works. Developer Micah Lee uses an idea he copied from Qubes TrustedPDF.

Qubes-OS doesn’t have it in vain the reputation of being one of the safest operating systems. But sure. Not everyone can or wants to install Qubes as an operating system. The idea that documents can be opened and edited in a secure environment is brilliant.

When launching containers, Dangerzone disables the network and the only file that gets mounted is the suspicious document itself. So if a malicious document breaks the container hacks, it won’t have access to your data and won’t be able to use the internet, so it can’t do much harm.

Micah Lee

Dangerzone uses Linux containers to open the various documents in a secure environment (sandbox). In contrast to TrustedPDF, the program does not only work with PDFs. Optical Character Recognition (OCR) is also used to provide the document with a searchable text layer.

Compatibility and requirements

  • As mentioned before, Dangerzone runs on Linux, Mac and Windows systems alike. In order to be able to use the program on Windows or Mac, however, Docker Desktop is required. The Docker desktop needs to be running in the background for the program to work.

    Dangerzone is second to none when it comes to compatibility. Because, as briefly mentioned before, not only PDFs or different Office documents are supported. The program also processes various image formats such as .jpeg or .gif without any problems.

        PDF (.pdf)

      • Microsoft Word (.docx, .doc)

      Excel (.xlsx, .xls)

      PowerPoint (.pptx, .ppt)

    • ODF Text (.odt)

    • Spreadsheet (.ods)

    • ODF Presentation (.odp)
    • ODF Graphics (.odg )

    Jpeg ( .jpg, .jpeg)

    GIF (.gif)

    PNG (.png)

  • TIFF (.tif, .tiff)

    As you can see, there are plenty of good reasons to join Dangerzone to install and take a closer look.

    Installing Dangerzone and Docker Desktop

    Depending , which operating system you have, you must of course first download and save the corresponding version of Dangerzone.

        Click here to download for Windows

      You can find the download for Mac here

      Download and installation instructions for Linux users

    In my case it was the download for Windows. At this point you should bring a little patience. Because the download weighs approx. 300 MB and unfortunately does not load too quickly.

    Dangerzone – the installation
  • Once downloaded, you start first the installer and follow the instructions.

    The installation of Dangerzone is quick and easy and doesn’t cause any problems. Once the installation is complete, we will be reminded of Docker Desktop.

    If you already have Docker Desktop installed, you need to open it now. Otherwise, just click on the link and select the appropriate operating system for you to download.

    Installing Docker Desktop is quick and hassle-free. Once you have Docker installed, we’re almost there. Now all we have to do is go back to the Dangerzone window and click Check Again.

    Here in this really well-made video tutorial by one of our readers, everything is explained and presented to you in great detail again.

    Dangerzone in action

    Danger Zone

      Now we finally have it done and you should see the Dangerzone welcome window. There you just have to click on “Select suspicious document” and select a compatible document.

      Now you can still specify where the newly created and secure document or image of your choice should be saved. Depending on the size of the file to be processed, you must now wait a moment.

      Dangerzone at work

    To A window will then open with the storage location you have selected. Finished. Now you have created a safe version, which you can open or edit without hesitation.

    But are we really completely on the safe side now and can we feel safe? No, unfortunately not quite.

    It’s still possible to get hacked

    Clearly, Micah Lee, Dangerzone makes it a lot easier for us to deal with documents or images where we can’t (or don’t want to) really trust the source.

    As with any software, it is possible that Dangerzone (and, more importantly, the software that it relies on, such as LibreOffice and Docker ) has security vulnerabilities.

    Micah Lee

    Clearly two watchful eyes are better than one. But to 90 % cannot be sure here either. Even though we’ve managed to make it at least a little harder for the bad guys, we should never neglect our vigilance.


    About Sunny

    Sunny has been writing since 2019 for the invisibility cloak. There he writes the reading tips and prefers to report on topics such as data protection, hacking and share hosting. But he can also be found again and again in our monthly commentary, in the interviews and in “Unter dem Radar” – the podcast by Tarnkappe.info.

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