The tool qpdf can be used to remove all unreferenced (old metadata) objects, that were removed with Exiftool to make it permanent This prevents that the tags cannot be restored. Some else can recover the metadata as they are actually never deleted, as follows exiftool -pdf-update:all= ORIGINAL_file.pdf IrreversibleĪfter using the Exiftool for editing, the tool qpdf can be used to linearize the pdf file in order to remove all the old metadata (which were replaced by nulls) to make the edits with Exiftool irreversible. The main disadvantage of edits with Exiftool is that the edits are reversible. exiftool -all:all= CLEAN_file.pdf -overwrite_original Hint: One way to create a useful reference file is to delete all the. exiftool -Title='This is the Title' -Author='Happy Man' -Subject='PDF Metadata' file.pdf -overwrite_originalĮxiftool can be used to remove all the metadata, in which case the metadata fields are replaced with nulls. Use this command to copy specific metadata tags from the reference file to other files. To copy or move metadata, the -tagsFromFile feature. Removal of metadataĮxiftool makes use of an incremental update technique to edit metadata. To write or delete metadata, tag values are assigned using the -TAGVALUE syntax, or the -geotag option.

This helps reduce the footprint which limits the reconnaissance capability of the attacking party.

Removal of metadata from a PDF file can be considered as an anti-forensic technique to limit the information contained in the file about the creator. Use Exiftool to run the following command shows all the current metadata in the PDF file.

Exiftool delete all metadata