- Paul Manafort court filing (U.S., 2019) Manafort’s lawyers filed a PDF where the “redacted” parts were basically black highlighting/boxes over live text. Reporters could recover the hidden text (e.g., via copy/paste).
- TSA “Standard Operating Procedures” manual (U.S., 2009) A publicly posted TSA screening document used black rectangles that did not remove the underlying text; the concealed content could be extracted. This led to extensive discussion and an Inspector General review.
- UK Ministry of Defence submarine security document (UK, 2011) A MoD report had “redacted” sections that could be revealed by copying/pasting the “blacked out” text—because the text was still present, just visually obscured.
- Apple v. Samsung ruling (U.S., 2011) A federal judge’s opinion attempted to redact passages, but the content was still recoverable due to the way the PDF was formatted; copying text out revealed the “redacted” parts.
- Associated Press + Facebook valuation estimate in court transcript (U.S., 2009) The AP reported it could read “redacted” portions of a court transcript by cut-and-paste (classic overlay-style failure). Secondary coverage notes the mechanism explicitly.
A broader “history of failures” compilation (multiple orgs / years) The PDF Association collected multiple incidents (including several above) and describes the common failure mode: black shapes drawn over text without deleting/sanitizing the underlying content. https://pdfa.org/wp-content/uploads/2020/06/High-Security-PD...
Anyway, if you click on a "redaction", you're clicking on the box and can't select the text underneath, but if you just highlight the text around it, you can copy all the original text.
It's a bizarre oversight.
PDF is an absurdly complex file format. It's part of the reason there is no single "good" PDF reader, just a lot of mediocre PDF readers that are all terrible in their own way. Which is a topic for another day.
There are several ways to remove data in a PDF:
- Remove the data. This is much harder than it sounds. Many PDF tools won't let you change the content of a PDF, not because it isn't possible, but because you'll likely massively screw up the formatting, and the tools don't want to deal with that.
- Replace the data. This what what all the "blackout" tools do, find "A" and replace with "🮋". This is effective and doesn't break formatting since it's a 1-to-1 replacement. The problem with "replacing" is that not every PDF tool works the same way, and some, instead, just change the foreground and background color to black; it looks nearly the same, but the power of copy-and-paste still functions.
- Then you have the computer illiterate, who think changing the foreground and background color to black is good enough anyway.
You can't possibly know that!
(Sorry, watching Grinch, Jim Carrey spoke through me).