Yara scanning PDF files

I am looking at option to automate the searching of a string in PDF files. For example, imagine a scenario where I need to find any pdf document, containing the string “confidential” in any pdf file on the disk of a laptop.
I can use pdf-parser and its YARA option for this.
For me, this has not given me any issues in the past. I was told however that for PDF, yara/string searches are very unreliable because of the way …

computerforensics confidential disk document file files find laptop pdf scanning scenario yara