CVE-2025-64155: THREE YEARS OF REMOTELY ROOTING THE FORTINET FORTISIEM

Summary from the TLDR InfoSec newsletter

A series of vulnerabilities in Fortinet's FortiSIEM platform allows a remote, unauthenticated attacker to gain full control of the appliance, from admin access to root. The weakness lies in how the phMonitor service processes certain storage-related requests, ultimately enabling crafted data to reach a curl-based health-check script and inject extra arguments. By abusing curl's features, an attacker can write arbitrary files as the FortiSIEM admin user and then leverage a writable script executed by root via cron to escalate privileges. Combined, these flaws permit long-term, stealthy compromise of FortiSIEM deployments.