Hidden Data and Metadata in Adobe PDF Files

[Elveon]

Publication Risks and Countermeasures...


The NSA produces a lot of documents about computer/applications security for their own purposes or for companies in the US.

The attached one is really well done, not to big (26 pages), clear with hard-copies and will and should concern everybody producing PDF documents for our propaganda goals.

1 Introduction
2 Background
3 PDF Structure
4 PDF Risk Areas
4.1 Metadata
4.2 Embedded Content and Attached Files
4.3 Scripts
4.4 Hidden Layers
4.5 Embedded Search Index
4.6 Stored Interactive Form Data
4.7 Reviewing and Commenting
4.8 Hidden Page, Image, and Update Data
4.9 Obscured Text and Images
4.10 PDF (Non-Displayed) Comments
4.11 Unreferenced Data
5 Removing Risk Area Content
5.1 Detailed Sanitization Procedure
6 Conclusion
References...

[Angharad]

A lot of the hidden data and metadata is found in other documents as well, such as MS Word or Excel. I am surprised there isn't more built in deliberately.

The company I used to work for changed their name, and I had to sanitize my documents per the request of company council. I still found documents by others with names of people who didn't work there, or the old company name years later. I think I was the only one in the company who actually knew how to do this.