- name
- analyzing-malicious-pdf-with-peepdf
- description
- Perform static analysis of malicious PDF documents using peepdf, pdfid, and pdf-parser to extract embedded JavaScript, shellcode, and suspicious objects. Use when triaging a suspicious PDF attachment from a phishing email, analyzing a PDF-based exploit document, or building detection signatures for weaponized PDF threats.
- domain
- cybersecurity
- subdomain
- malware-analysis
- tags
- ["malware-analysis","pdf","peepdf","pdfid","pdf-parser","static-analysis","reverse-engineering","dfir"]
- version
- 1.0
- author
- mahipal
- license
- Apache-2.0
- nist_csf
- ["DE.AE-02","RS.AN-03","ID.RA-01","DE.CM-01"]
- mitre_attack
- ["T1204.002","T1059.007","T1027","T1106"]
# Analyzing Malicious PDF with peepdf
## When to Use
- When triaging suspicious PDF attachments from phishing emails
- During malware analysis of PDF-based exploit documents
- When extracting embedded JavaScript, shellcode, or executables from PDFs
- For forensic examination of weaponized document artifacts
- When building detection signatures for PDF-based threats
## Prerequisites
- Python 3.8+ with peepdf-3 installed (pip install peepdf-3)
- pdfid.py and pdf-parser.py from Didier Stevens suite
- Isolated analysis environment (VM or sandbox)
- Optional: PyV8 for JavaScript emulation within peepdf
- Optional: Pylibemu for shellcode analysis
## Workflow
1. **Triage with pdfid**: Scan PDF for suspicious keywords (/JS, /JavaScript, /OpenAction, /Launch, /EmbeddedFile).
2. **Interactive Analysis**: Open PDF in peepdf interactive mode to explore object structure.
3. **Identify Suspicious Objects**: Locate objects containing JavaScript, streams, or encoded data.
4. **Extract Content**: Dump suspicious streams and decode filters (FlateDecode, ASCIIHexDecode).
5. **Deobfuscate JavaScript**: Analyze extracted JS for shellcode, heap sprays, or exploit code.
6. **Check VirusTotal**: Use peepdf vtcheck to cross-reference file hash with AV detections.
7. **Generate IOCs**: Extract URLs, domains, hashes, and shellcode signatures.
## Key Concepts
| Concept | Description |
|---------|-------------|
| /OpenAction | Automatic action executed when PDF is opened |
| /JavaScript /JS | Embedded JavaScript code in PDF objects |
| /Launch | Action that launches external applications |
| /EmbeddedFile | File embedded within the PDF structure |
| FlateDecode | zlib compression filter used to hide content |
| Object Streams | PDF objects stored in compressed streams |
## Tools & Systems
| Tool | Purpose |
|------|---------|
| peepdf / peepdf-3 | Interactive PDF analysis with JS emulation |
| pdfid.py | Quick triage scanning for suspicious keywords |
| pdf-parser.py | Deep object-level PDF parsing |
| VirusTotal | Hash lookup and AV detection cross-reference |
| CyberChef | Decode and transform extracted payloads |
## Output Format
```
Analysis Report: PDF-MAL-[DATE]-[SEQ]
File: [filename.pdf]
SHA-256: [hash]
Suspicious Keywords: [/JS, /OpenAction, etc.]
Objects with JavaScript: [Object IDs]
Extracted URLs: [List]
Shellcode Detected: [Yes/No]
Embedded Files: [Count and types]
VirusTotal Detections: [X/Y engines]
Risk Level: [Critical/High/Medium/Low]
```
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