# Analyzing Malicious Pdfs

> Analyzes malicious PDF documents: parsing the object structure for JavaScript,

- **Type:** Skill
- **Install:** `agentstack add skill-meltedinhex-analyst-ai-pack-analyzing-malicious-pdfs`
- **Verified:** Yes — security-reviewed for prompt injection and unsafe behavior
- **Seller:** [meltedinhex](https://agentstack.voostack.com/s/meltedinhex)
- **Installs:** 0
- **Category:** [Content & Media](https://agentstack.voostack.com/c/content-and-media)
- **Latest version:** 0.1.0
- **License:** Apache-2.0
- **Upstream author:** [meltedinhex](https://github.com/meltedinhex)
- **Source:** https://github.com/meltedinhex/analyst-ai-pack/tree/main/skills/analyzing-malicious-pdfs
- **Website:** https://meltedinhex.com/

## Install

```sh
agentstack add skill-meltedinhex-analyst-ai-pack-analyzing-malicious-pdfs
```

Requires the [AgentStack CLI](https://agentstack.voostack.com/docs/cli). Works with Claude Code, Cursor, and any MCP-compatible agent.

## About

# Analyzing Malicious PDFs

## When to Use

- You have a suspicious PDF (often from phishing) and must determine if it is weaponized.
- You need to find auto-executing actions, embedded JavaScript, launch actions, or embedded files.
- You want to extract and decode suspicious streams safely.

**Do not use** a PDF reader to "just look" — opening in a viewer can trigger the very actions you
are investigating. Parse the structure statically.

## Prerequisites

- A PDF object parser (Python, or pdfid/pdf-parser/peepdf); the sample handled inertly.

## Safety & Handling

- Never open the PDF in a graphical reader; parse the raw object structure only.
- Defang any extracted URLs and store embedded payloads password-protected.

## Workflow

### Step 1: Triage the object inventory

Count high-risk keywords: `/JavaScript`, `/JS`, `/OpenAction`, `/AA`, `/Launch`, `/EmbeddedFile`,
`/URI`, `/RichMedia`. Their presence (especially auto-actions) flags weaponization.

```bash
python scripts/analyst.py triage sample.pdf
```

### Step 2: Locate auto-execution triggers

Resolve `/OpenAction` and `/AA` (additional actions) to see what runs on open, and any `/Launch`
actions that spawn external programs.

### Step 3: Extract and decode streams

Pull JavaScript and suspicious streams, applying filters (`/FlateDecode`, `/ASCIIHexDecode`) to
get the cleartext; deobfuscate layered JS as needed.

### Step 4: Recover payloads and IOCs

Extract embedded files and URIs; hash payloads, defang URLs, and route extracted executables to
PE analysis.

## Validation

- Auto-execution triggers (`/OpenAction`, `/AA`, `/Launch`) are resolved to concrete actions.
- JavaScript/streams are decoded through their filters, not left encoded.
- Embedded payloads and URIs are extracted, hashed, and defanged.

## Pitfalls

- Opening the PDF in a reader and triggering the payload.
- Missing object-stream (`/ObjStm`) compressed objects that hide the malicious content.
- Stopping at the first JS layer when it is multiply obfuscated.

## References

- See [`references/api-reference.md`](references/api-reference.md) for the PDF triage parser.
- ISO 32000 and Didier Stevens' PDF tools (linked in frontmatter).

## Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

- **Author:** [meltedinhex](https://github.com/meltedinhex)
- **Source:** [meltedinhex/analyst-ai-pack](https://github.com/meltedinhex/analyst-ai-pack)
- **License:** Apache-2.0
- **Homepage:** https://meltedinhex.com/

Install and usage instructions live in the source repository linked above.

## Pricing

- **Free** — Free

## Security capabilities

Automated source analysis of v0.1.0 — what this tool can access:

- **Network access:** no
- **Filesystem access:** no
- **Shell / process execution:** no
- **Environment & secrets:** no
- **Dynamic code execution:** no

*"Yes" means the capability is present in the source — more access means more to trust, not that it is unsafe.*


## Versions

- **0.1.0** — security scan: passed — Imported from the upstream source.

## Links

- Listing page: https://agentstack.voostack.com/l/skill-meltedinhex-analyst-ai-pack-analyzing-malicious-pdfs
- Seller: https://agentstack.voostack.com/s/meltedinhex
- Browse the marketplace: https://agentstack.voostack.com/browse

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