- Plesk Onyx for Linux
ModSecurity was just installed via Plesk Installer, but was not enabled in Plesk in Tools & Settings > Web Application Firewall (ModSecurity).
The command below showed that the ModSecurity is loaded already
# httpd -M | grep sec
error_logfile contains ModSecurity actions entries:
CONFIG_TEXT: ModSecurity: Access denied with code 44 (phase 2). Match of "eq 0" against "MULTIPART_UNMATCHED_BOUNDARY" required.
Plesk product bug #PPPM-8578
Enable ModSecurity in Plesk Tools & Settings > Web Application Firewall (ModSecurity) and then disable it back.