Hackers Exploit WordPress mu-Plugins to Inject Spam and Hijack Site Images
Mar 31, 2025
Data Theft / Website Security
Threat actors are using the "mu-plugins" directory in WordPress sites to conceal malicious code with the goal of maintaining persistent remote access and redirecting site visitors to bogus sites. mu-plugins, short for must-use plugins , refers to plugins in a special directory ("wp-content/mu-plugins") that are automatically executed by WordPress without the need to enable them explicitly via the admin dashboard. This also makes the directory an ideal location for staging malware. "This approach represents a concerning trend, as the mu-plugins (Must-Use plugins) are not listed in the standard WordPress plugin interface, making them less noticeable and easier for users to ignore during routine security checks," Sucuri researcher Puja Srivastava said in an analysis. In the incidents analyzed by the website security company, three different kinds of rogue PHP code have been discovered in the directory - "wp-content/mu-plugins/redirect.php," ...
