Phusion Passenger chown() race privilege escalation (CVE-2018-12029)

Jun 13 2018

Phusion Passenger’s Nginx module is vulnerable to a privilege escalation vulnerability when run with a non-standard passenger_instance_registry_dir configuration. A vulnerability exists when creating the control_process.pid file, specifically when the file’s owner is changed from root. An attacker can use this behavior to escalate privileges from the www-data user to the root user when Nginx is restarted.

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