In the last few months, we have discovered a number of supply chain attacks targeting WordPress plugins. In this post, we explain what a supply chain attack is, why WordPress is an attractive target for them, and what you can do to protect your site.

In the software industry, a supply chain attack exploits a trusted relationship between software vendors or authors and their customers. For WordPress, that means figuring out how to embed malware into software updates.

In one case, we saw an existing plugin author install malware on customer sites in an effort to monetize an existing plugin. In every other case we have uncovered, the attack was carried out by someone who had purchased the plugin with the express intention of attacking its users.