An anonymous reader writes: Nearly 5,500 WordPress sites are infected with a malicious script that logs keystrokes and sometimes loads an in-browser cryptocurrency miner. The malicious script is being loaded from the "cloudflare.solutions" domain, which is not affiliated with Cloudflare in any way, and logs anything that users type inside form fields as soon as the user switches away from an input field. The script is included on both the sites' frontends and backends, meaning it can steal both admin account credentials and credit card data from WP sites running e-commerce stores. According to site source code search engine PublicWWW, there are 5,496 sites running this keylogger. The attacker has been active since April.