# PDF Prompt Injection Scanner Compare safe and unsafe PDF extraction runs to detect hidden text, off-page content, tiny text, and hidden-layer prompt injection risks > Canonical page: https://elysiatools.com/en/tools/pdf-prompt-injection-scanner - **Category:** Security - **Keywords:** pdf, prompt injection, hidden text, off-page, security ## Overview Run OpenDataLoader with default safety filtering and compare it against targeted unsafe runs where one safety category is disabled at a time. The tool highlights extra text that only appears when a specific filter is removed, which is a practical signal for hidden prompt-injection attempts in PDF workflows. ## Inputs - **PDF File** (file) - **Scan Hidden Text** (checkbox) - **Scan Off-page Content** (checkbox) - **Scan Tiny Text** (checkbox) - **Scan Hidden Layers** (checkbox) - **Use Struct Tree** (checkbox) - **Sanitize Sensitive Data** (checkbox) ## When to use - Before feeding user-uploaded PDFs into an LLM or RAG pipeline. - When auditing untrusted documents for hidden text, off-page content, or tiny fonts. - To verify the safety of third-party reports or resumes against prompt injection attacks. ## How it works - Upload a PDF file to the scanner. - Select the specific risk categories to scan, such as hidden text, off-page content, tiny text, or hidden layers. - The tool runs multiple extractions, comparing a default safe run against unsafe runs where individual filters are disabled. - Review the generated HTML report to inspect any suspicious text snippets that only appear when safety filters are bypassed. ## Use cases - Securing automated resume screening systems against applicants hiding invisible keywords or LLM instructions. - Pre-processing financial reports or legal contracts in RAG pipelines to ensure no malicious prompts manipulate the AI's summary. - Auditing untrusted, user-generated PDF uploads in web applications for hidden layer vulnerabilities. ## Frequently asked questions ### What is a PDF prompt injection? It is a security vulnerability where malicious instructions are hidden inside a PDF using tiny text, hidden layers, or off-page placement to manipulate the behavior of an AI reading the document. ### How does this scanner detect hidden text? It extracts the PDF text twice: once with safety filters enabled and once with them disabled. Any text that only appears in the unfiltered run is flagged as potentially hidden. ### What types of risks can it scan for? The tool can scan for hidden text, off-page content, tiny text, and hidden layers (OCG). ### Can I sanitize sensitive data during the scan? Yes, you can enable the Sanitize Sensitive Data option to redact sensitive information while scanning for injection risks. ### What format is the scan report? The tool generates an HTML report featuring category badges and previews of the suspicious text snippets found in the document. ## Related tools - [OCR PDF to Structured JSON Bridge](https://elysiatools.com/en/tools/ocr-pdf-to-structured-json-bridge): Extract the PDF text layer with geometry (lines by y-position, tables by column gaps, headings by font size, colon key-value pairs), then fill a user-supplied JSON Schema field by field — labels matched by normalized keys, values coerced to declared types and validated with ajv. - [PDF Header/Footer Noise Remover](https://elysiatools.com/en/tools/pdf-header-footer-noise-remover): Compare extraction with and without repeated page furniture to spot header/footer noise before using PDF text in RAG, summarization, or editing workflows - [PDF Text Extractor](https://elysiatools.com/en/tools/pdf-text-extractor): Extract text content from PDF documents with support for page selection, formatting options, and multi-language processing - [PDF to Clean Text for LLM](https://elysiatools.com/en/tools/pdf-to-clean-text-for-llm): Extract clean text from PDFs with OpenDataLoader for summarization, translation, embedding, and other LLM workflows - [PDF to Markdown Converter](https://elysiatools.com/en/tools/pdf-to-markdown): Convert PDF documents to Markdown format with text extraction and formatting preservation - [PDF to PowerPoint](https://elysiatools.com/en/tools/pdf-to-powerpoint): Extract text content from PDF files and convert to PowerPoint presentation slides - [PDF to Text Advanced](https://elysiatools.com/en/tools/pdf-to-text-advanced): Advanced PDF to text converter with page selection, formatting options, and metadata extraction - [PDF to Word](https://elysiatools.com/en/tools/pdf-to-word): Convert PDF files to editable Word documents (.docx) by extracting text and preserving basic formatting ## Samples - [PDF Samples](https://elysiatools.com/en/samples/pdf-samples): Generated PDF samples from tools dated 2026-02-01 to 2026-02-10 - [Markdown Slide Deck Samples](https://elysiatools.com/en/samples/md-slide-deck-to-pdf): Remark/Marp style Markdown slide decks for testing PDF export layouts - [SQL Injection Samples](https://elysiatools.com/en/samples/sql-injections): Educational collection of SQL injection payloads for security testing, vulnerability assessment, and defensive coding practices - [Prompt Engineering Samples](https://elysiatools.com/en/samples/prompt-engineering): Comprehensive prompt engineering examples including templates, best practices, and techniques for effective AI communication ## Related content - [PDF Extraction and Debugging Workflows](https://elysiatools.com/en/hubs/pdf-extraction-debugging-workflows): Debug hard PDF extraction cases by checking encryption, safety, page scope, reading order, OCR, tables, review marks, and structured output. - [PDF LLM and RAG Preparation](https://elysiatools.com/en/hubs/pdf-llm-rag-prep): Turn PDFs into clean, safe, citation-ready inputs for LLM summarization, embedding, search, and RAG pipelines. - [Prompt Engineering and LLM Input Preparation](https://elysiatools.com/en/hubs/prompt-engineering-llm-input-workflows): Prepare LLM inputs by structuring prompts, checking token budgets, translating or identifying language, cleaning PDF evidence, and reviewing injection, math, regex, and data risks before use. - [RAG Chunking and Retrieval Prep](https://elysiatools.com/en/hubs/rag-chunking-retrieval-prep): Clean PDFs and Word files, remove extraction noise, scan hidden prompt risks, split text, score chunk quality, and package citation-ready RAG inputs.