How to remove file metadata for your privacy on Linux.
In a previous article, I discussed how metadata embedded in images can jeopardize your privacy and reveal personal information about you. Care should be taken when sharing and posting photos, and the same can be said about the documents you share with others.
A typical data file often has associated “metadata” which is descriptive information about the file such as the creator’s name, tools used to generate the file, file creation/update date, location of creation, editing history, etc. Tools are available on all platforms to “clean” those files, and today I am going to discuss one of those. Special thanks to an anonymous “guest blogger” for helping to explain this powerful, easy to use Linux tool.
To review, EXIF metadata in photo images can reveal personally identifiable information such as your camera model, GPS coordinate of shooting, your favorite photo editor software, etc. Metadata in documents and spreadsheets contain author/company information and other editing history. Every photo you take or document that is created on your machine has metadata attached. Whether you post the photo online or send a picture text, the metadata travels along with the file and can be extracted by someone else.
While the extraction methods might seem complicated, investigators, penetration testers, hackers, and even criminals use metadata gathering tools often to uncover detailed information about their targets.
Consider this scenario: you have recently relocated to a new city because you had a violent stalker. As you get settled into your new life and the storm calms, you take what you think is a harmless selfie that contained no identifying objects that would expose your location and send it to a family member. This family member then uploads the photo to social media because they are “proud of the life change you made” and want to share the joy with others. This could be a fatal mistake if the photo still has metadata intact. Remember the violent stalker from your past? Get ready to be re-united as he has been monitoring your family’s social media accounts and now knows your exact location from the embedded metadata.
For the privacy conscious individuals interested in stripping all metadata from shared media, Linux offers a great solution; MAT (Meta Data Anonymisation Toolkit). MAT is a simple, yet extremely useful tool to prevent any inadvertent privacy leaks by eliminating metadata from a wide variety of file types such as images, documents, PDF’s, audio files, etc.
1) Start the Terminal and type “sudo apt install mat”
2) Provide your admin password as needed and press “enter”
3) MAT will be installed and an icon will automatically be placed in the applications list
1) Double click on the program icon
2) To add a file to clean, click on the “Add” Icon. Select your file and upload it or you can drag your selected files into the MAT program window.
3) Once any metadata is detected by MAT, the “State” field will be marked as “Dirty”
4) To view the current metadata of each file, double click on the word “Dirty” and a new window will open
5) Finally, to clean up metadata from the file, click on the “Clean” icon. MAT will automatically remove all private metadata fields from the file. Once completed the “State” field will be marked as “Clean”
How I use MAT
Before any file leaves my computer it is cleaned by MAT. Photos and documents that are emailed, posted, or shared via messaging apps are first run through MAT to ensure that no metadata remains that could be analyzed by the recipient or someone else who may end up with that file later on. The process of cleaning a file is simple and fast, and has become a standard procedure in my work flow.
If you are a Linux user, the Meta Data Anonymisation Toolkit is a must have application, and I hope this article explained how easy it is to control and protect the data that you share.