How to check a PDF for hidden information
Published 26 Sept 2026 · Sumit · Privacy
Hidden information usually means document properties, text you forgot on page 40, or embedded files. No single scan catches everything, but a short checklist catches most everyday leaks.
Use PDF info and Remove metadata for properties; Privacy scanner for common PII patterns; Extract attachments if the format may carry embedded files.
Step by step
- 1Open PDF info and note author, title, and dates.
- 2Run Privacy scanner and review matches.
- 3Check for attachments if your viewer or Extract attachments lists any.
- 4Strip metadata; redact page content that should not ship; re-check the download.
What automated scans miss
Project codenames, “confidential” only from context, and secrets inside images without OCR. Human reading remains required for high-stakes documents.
Limits
- Pattern scanners are incomplete by design.
- Metadata strip is not a full forensic wipe.
- Always verify the file you are about to send.
Tools used here
- PDF infoInspect page count, dimensions, and document metadata.
- Privacy scannerScan a PDF for PII patterns and report what was found, without removing it.
- Remove metadataClear common Info fields (title, author, subject, keywords, dates). Does not scrub every hidden stream.
- Extract attachmentsPull embedded file attachments out of the PDF.
- RedactDraw black boxes over sensitive regions. Matched pages are rasterized so covered text is destroyed.
Frequently asked questions
Does inspection upload my PDF?
No. These tools run in your browser.Is a clean scan a guarantee?
No. It is a strong first pass. Read the document when the stakes are high.
Related guides
More in privacy- Remove a PDF passwordStrip the password from a document you have the right to open, without uploading it.
- Redact before sharingWhy black rectangles are not redaction, and how to remove content so it stays removed.
- Unlock a PDF legallyRemove protection from a document you are allowed to open — with the password, not a crack.
- Are online PDF tools safe?Upload-based tools keep copies under their policies; local tools never need the file.
- PDF privacy guideA clear picture of upload pipelines vs in-browser processing — and how to share PDFs with less risk.
- Remove PDF metadataStrip common author and document Info fields before you share — locally.