Jul 26, 2022
As many as 207 websites have been infected with malicious code designed to launch a cryptocurrency miner by leveraging WebAssembly (Wasm) on the browser. Web security company Sucuri, which published details of the campaign, said it launched an investigation after one of its clients had their computer slowed down significantly every time upon navigating to their own WordPress portal. This uncovered a compromise of a theme file to inject malicious JavaScript code from a remote server -- hxxps://wm.bmwebm[.]org/auto.js -- that's loaded whenever the website's page is accessed. "Once decoded, the contents of auto.js immediately reveal the functionality of a cryptominer which starts mining when a visitor lands on the compromised site," Sucuri malware researcher Cesar Anjos said . What's more, the deobfuscated auto.js code makes use of WebAssembly to run low-level binary code directly on the browser. WebAssembly , which is supported by all major browsers, is a b