Adult sites are stashing exploit code inside racy .svg files

The obfuscated code inside an .svg file downloaded from one of the porn sites.

Credit:
Malwarebytes

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.”

Malicious uses of the .svg format have been documented before. In 2023, pro-Russian hackers used an .svg tag to exploit a cross-site scripting bug in Roundcube, a server application that was used by more than 1,000 webmail services and millions of their end users. In June, researchers documented a phishing attack that used an .svg file to open a fake Microsoft login screen with the target’s email address already filled in.

Arntz said that Malwarebytes has identified dozens of porn sites, all running on the WordPress content management system, that are abusing the .svg files like this for hijacking likes. Facebook regularly shuts down accounts that engage in these sorts of abuse. The scofflaws regularly return using new profiles.