Pi-hole: Local privilege escalation from `pihole` user to root via `/etc/pihole/logrotate`

Pi-hole is a DNS sinkhole that protects devices from unwanted content without installing any client-side software. From 6.0 to 6.4.2, a user with code execution as the unprivileged pihole user can escalate to root by replacing /etc/pihole/logrotate. The replacement is laundered to root:root ownership by pihole-FTL-prestart.sh and then parsed as root by the daily pihole flush cron, executing firstaction shell as uid 0. This issue is fixed in version 6.4.3.