analyzing-malicious-pdf-with-peepdf

analyzing-malicious-pdf-with-peepdf is a skill for Claude Code from plurigrid/asi. It costs 43 tokens per session (701 once invoked), scanned A, a copy of analyzing-malicious-pdf-with-peepdf, MIT.

A guide to safely inspecting suspicious PDF files for embedded JavaScript, shellcode, executable content, and other active objects. It uses PDF structure and malware-analysis tools rather than opening the document normally.

In plain words
What is it for?
Use it to triage suspicious PDF attachments, extract embedded content, analyze exploit code, and create detection signatures for malicious PDFs.
Why use it?
It helps analysts examine phishing attachments and weaponized PDFs without accidentally running their embedded content. It also helps reveal obfuscated code and the parts of a document that need closer review.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the asi plugin — 56 skills shipped together

Good fit Use it to triage suspicious PDF attachments, extract embedded content, analyze exploit code, and create detection signatures for malicious PDFs.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add plurigrid/asi --skill analyzing-malicious-pdf-with-peepdf
Clone the repo
git clone --depth 1 https://github.com/plurigrid/asi

Made for: Claude Code.

Or install asi, the plugin that ships this one along with the rest of its 56 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for analyzing-malicious-pdf-with-peepdf

README.md
[![agentmods](https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf/github.svg)](https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf)
Your own site
<a href="https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for analyzing-malicious-pdf-with-peepdf

Your own site · 80×15
<a href="https://agentmods.dev/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf"><img src="https://agentmods.dev/badge/skills/plurigrid/asi/analyzing-malicious-pdf-with-peepdf.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 701 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 86% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00043 $0.00701
Opus 5 $0.00022 $0.00351
Sonnet 5 $0.00009 $0.00140
Haiku 4.5 $0.00004 $0.00070

Measured 8d ago against content hash bbe4fe66b675, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

analyzing-malicious-pdf-with-peepdf scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

86% identical to analyzing-malicious-pdf-with-peepdf — 28 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/asi/skills/analyzing-malicious-pdf-with-peepdf/SKILL.md · 75 lines

How it starts

The opening of the file, as written. The whole thing — 75 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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

Read the full file on GitHub · 75 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 75 lines · 43 tokens per session scan A bbe4fe66b675

Subscribe to this mod's changes

analyzing-malicious-pdf-with-peepdf is a skill published in the GitHub repository plurigrid/asi (64 stars, last pushed 2mo ago), licensed MIT. It adds 43 tokens to every session and 701 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 86% identical to analyzing-malicious-pdf-with-peepdf, differing in 28 lines, and is treated as a copy.

Related

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