Unsichere Verwendung von temporären Dateien in passenger

The vulnerability lies in how Phusion Passenger handles symlinks to files like control_process.pid and files starting with generation-. A malicious local user can create a symlink pointing to a file they control. When Passenger attempts to access the original file, it inadvertently writes to the attacker's chosen location. This could allow an attacker to overwrite critical configuration files, potentially leading to denial of service or, in more complex scenarios, privilege escalation if the overwritten file controls access to sensitive resources. While the vulnerability is rated LOW, the ease of exploitation and potential for disruption warrant prompt remediation.

1. Veröffentlicht2018-10-10
2. Geändert2024-12-08
3. EPSS aktualisiert2026-04-02

The primary mitigation is to upgrade Phusion Passenger to version 4.0.38 or later, which contains the fix. If upgrading immediately is not feasible, consider restricting write access to the control_process.pid and generation-* directories to the Passenger user only. Carefully review file permissions and ownership within the Passenger installation directory. Monitor system logs for suspicious file modification activity, particularly targeting these specific files. After upgrade, confirm the fix by attempting to create a symlink to a file outside the Passenger directory and verifying that Passenger does not write to it.