Cybersecurity researchers have disclosed details of a remote Spectre attack against Cloudflare Workers that leaked a JSON Web Token (JWT) from a co-located Worker in the production environment at up to 12 bits per second, 360 times the rate of an earlier attack demonstrated in 2021. The end-to-end experiment used an attacker Worker and a victim Worker controlled by the researchers, with the JWT intentionally placed in the victim's memory. The research paper stated that no customer data was accessed. Cloudflare said the attack has already been mitigated in production after it improved Dynamic Process Isolation (DyPrIs), integrated the V8 Sandbox, and deployed Memory Protection Keys (MPK)-based in-process isolation, adding that it found no indicators of active exploitation over the last…