Michael Wolff’s book on the Trump presidency Fire and Fury has everything: from Bannon mouthing off against Trump’s son to claims that Trump was despondent when he won the election. But some dodgy, unofficial versions of the book contain an extra-special bonus: malware.

To be absolutely clear: Malware is not affecting the ordinary, retail copy of Fire and Fury, but files linked to a PDF version circulating online. The dangerous types are the pirated PDFs you’d find in Google searches and on torrent sites, but not ones on traditional ebook retailers like Apple Books or Amazon.

Still, the gambit shows some of the downright bizarre hooks criminals, hackers, or pranksters may use to spread malware—including juicy entries from the nonfiction rack.

Michael Molsner from cybersecurity firm Kaspersky first highlighted the malware on Twitter on Friday. The bundle of files includes the PDF of Fire and Fury, and a Windows executable file, or .exe. Notably, the PDF only contains just over 230 pages, rather than the full, 328-page version.

WikiLeaks shared a link to a PDF of the full version earlier this month, while Cryptome, another activist group, published the trimmed copy apparently used with this malware.

At the time of writing, both of those links are unresponsive, with one saying the PDF was removed due to a violation of Google’s terms of service.

The Daily Beast obtained a sample of the malware, and processed it through an online analysis service, which marked the files as a so-called backdoor. A backdoor may give hackers remote access to a victim’s computer.

It’s not the most exciting or underground malware in the world: A slew of antivirus programs detect the malicious program, according to results from malware analysis site Virus Total.

But, if someone unsolicitedly sends you a several hundred-page PDF of embarrassing Trump anecdotes, maybe think twice about opening it.