Adult Sites Are Stashing Exploit Code Inside Racy .svg Files
An Anonymous Coward writes:
https://arstechnica.com/security/2025/08/adult-sites-use-malicious-svg-files-to-rack-up-likes-on-facebook/
https://archive.ph/lzs6b
Running JavaScript from inside an image? What could possibly go wrong?
Dozens of porn sites are turning to a familiar source to generate likes on Facebook-malware that causes browsers to surreptitiously endorse the sites. This time, the sites are using a newer vehicle for sowing this malware-.svg image files.
The Scalable Vector Graphics format is an open standard for rendering two-dimensional graphics. Unlike more common formats such as .jpg or .png, .svg uses XML-based text to specify how the image should appear, allowing files to be resized without losing quality due to pixelation. But therein lies the rub: The text in these files can incorporate HTML and JavaScript, and that, in turn, opens the risk of them being abused for a range of attacks, including cross-site scripting, HTML injection, and denial of service.
Security firm Malwarebytes on Friday said it recently discovered that porn sites have been seeding boobytrapped .svg files to select visitors. When one of these people clicks on the image, it causes browsers to surreptitiously register a like for Facebook posts promoting the site.
Unpacking the attack took work because much of the JavaScript in the .svg images was heavily obscured using a custom version of "JSFuck," a technique that uses only a handful of character types to encode JavaScript into a camouflaged wall of text.
Once decoded, the script causes the browser to download a chain of additional obfuscated JavaScript. The final payload, a known malicious script called Trojan.JS.Likejack, induces the browser to like a specified Facebook post as long as a user has their account open.
"This Trojan, also written in Javascript, silently clicks a 'Like' button for a Facebook page without the user's knowledge or consent, in this case the adult posts we found above," Malwarebytes researcher Pieter Arntz wrote. "The user will have to be logged in on Facebook for this to work, but we know many people keep Facebook open for easy access."
Related: Trojans Embedded in .svg Files
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