How PDF Fraud Happens and Why It's Difficult to Spot PDF files are ubiquitous for invoices, receipts, contracts, and official records, but their familiarity makes them a prime target for fraudsters. Many attackers exploit the assumption that PDFs are static and unchangeable, embedding altered images, swapped text layers, or forged metadata to create convincing fake documents. A forged PDF may combine a legitimate header with manipulated line items, or overlay new content on top of an exported image to hide edits. Understanding the tactics used is the first step toward effective detection. Some of the most common strategies include altering metadata to mislead about authorship and timestamps, using fonts that…