analyzing-malicious-pdf-with-peepdf

Perform static analysis of malicious PDF documents using peepdf, pdfid, and pdf-parser to extract embedded JavaScript, shellcode, and suspicious objects.

16 stars

byplurigrid

View on GitHub Installation ↓

Best use case

analyzing-malicious-pdf-with-peepdf is best used when you need a repeatable AI agent workflow instead of a one-off prompt.

Perform static analysis of malicious PDF documents using peepdf, pdfid, and pdf-parser to extract embedded JavaScript, shellcode, and suspicious objects.

Teams using analyzing-malicious-pdf-with-peepdf should expect a more consistent output, faster repeated execution, less prompt rewriting.

When to use this skill

You want a reusable workflow that can be run more than once with consistent structure.

When not to use this skill

You only need a quick one-off answer and do not need a reusable workflow.
You cannot install or maintain the underlying files, dependencies, or repository context.

Installation

Claude Code / Cursor / Codex

$curl -o ~/.claude/skills/analyzing-malicious-pdf-with-peepdf/SKILL.md --create-dirs "https://raw.githubusercontent.com/plurigrid/asi/main/plugins/asi/skills/analyzing-malicious-pdf-with-peepdf/SKILL.md"

Manual Installation

Download SKILL.md from GitHub
Place it in .claude/skills/analyzing-malicious-pdf-with-peepdf/SKILL.md inside your project
Restart your AI agent — it will auto-discover the skill

How analyzing-malicious-pdf-with-peepdf Compares

Feature / Agent	analyzing-malicious-pdf-with-peepdf	Standard Approach
Platform Support	Not specified	Limited / Varies
Context Awareness	High	Baseline
Installation Complexity	Unknown	N/A

Frequently Asked Questions

What does this skill do?

Perform static analysis of malicious PDF documents using peepdf, pdfid, and pdf-parser to extract embedded JavaScript, shellcode, and suspicious objects.

Where can I find the source code?

You can find the source code on GitHub using the link provided at the top of the page.

SKILL.md Source

# 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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