This PDF contains a playable copy of Doom
Adobe Acrobat's little-used JavaScript support gets exploited in Chromium browsers.
Here at Ars, we're suckers for stories about hackers getting Doom running on everything from CAPTCHA robot checks and Windows' notepad.exe to AI hallucinations and fluorescing gut bacteria. Despite all that experience, we were still thrown for a loop by a recent demonstration of Doom running in the usually static confines of a PDF file.
On the Github page for the quixotic project, coder ading2210 discusses how Adobe Acrobat included some robust support for JavaScript in the PDF file format. That JS coding support—which dates back decades and is still fully documented in Adobe's official PDF specs—is currently implemented in a more limited, more secure form as part of PDFium, the built-in PDF-rendering engine of Chromium-based browsers.
In the past, hackers have used this little-known Adobe feature to code simple games like Breakout and Tetris into PDF documents. But ading220 went further, recompiling a streamlined fork of Doom's open source code using an old version of Emscripten that outputs optimized asm.js code.
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