| Step | Observation | Screenshot | |------|-------------|------------| | | PDF document, version 1.6 | ![file-header] | | Metadata | Creator: Microsoft Word ; Producer: AcroPDF ; CreationDate: 2023‑11‑02T08:13:00Z | ![metadata] | | Objects | /JavaScript object found in page 3 ( /AA << /O << /JS (app.alert('Gotcha')) >> >> ) | ![object] | | Embedded file | payload.exe (size 24 KB) extracted via binwalk | ![embedded] | | VirusTotal | 98/100 AV engines flagged as Trojan.GenericKD.3214 | ![vt] |
$ pdf-parser.py -s rzh\ rbyn\ –\ swdwt\ wsqrym.pdf Search for , /JavaScript , /AA (Additional Actions), or /OpenAction objects. These are typical vectors for malicious payloads. 4.4. Search for embedded files $ binwalk -e rzh\ rbyn\ –\ swdwt\ wsqrym.pdf If you find a payload.exe or payload.dll inside the PDF, you’ve got a classic “PDF‑dropper”. 4.5. Render safely with PDF.js (headless) $ docker run --rm -v "$(pwd)":/data -w /data node:20 \ bash -c "npm install -g pdfjs-dist && \ node -e \"const pdfjs = require('pdfjs-dist/legacy/build/pdf.js'); \ const fs = require('fs'); \ const data = new Uint8Array(fs.readFileSync('rzh rbyn – swdwt wsqrym.pdf')); \ pdfjs.getDocument(data).promise.then(doc=>doc.getMetadata()).then(m=>console.log(m)).catch(console.error);\"" If the script crashes, the PDF may be using obfuscated streams or malformed objects to trigger vulnerabilities. 5. What to Do When You Find Something Suspicious | Finding | Recommended Action | |-------------|------------------------| | Embedded executable | Submit to VirusTotal, then delete the PDF. | | Obfuscated JavaScript | De‑obfuscate with js-beautify or unuglifyjs in a sandbox. | | Encrypted streams (e.g., obj 5 0 obj <</Filter /FlateDecode /Length 1234>> ) | Try to decrypt with qpdf --decrypt . If a password is required, it’s a document protection feature, not necessarily malicious. | | Suspicious metadata (e.g., “Created by: EvilCorp”) | Treat as a threat indicator and add to your SIEM. | | Nothing odd | Still keep a hash ( sha256sum ) for future reference. | 6. A Real‑World Example (Illustrated) Below is a sanitized walkthrough of an actual “mystery PDF” we encountered in early 2025. The steps are identical to the checklist above.
If you’ve already opened the file or found something interesting, feel free to drop a comment below—share the hash, the findings, or even the solved title (if it turns out to be a cipher). Collaboration is the fastest path from mystery to knowledge.
rzh rbyn – swdwt wsqrym.pdf A quick Caesar‑shift analysis reveals a plausible English phrase when shifting each letter :