CVE-2019-12578

/// Technical description

A vulnerability in the London Trust Media Private Internet Access (PIA) VPN Client v82 for Linux could allow an authenticated, local attacker to run arbitrary code with elevated privileges. The openvpn_launcher.64 binary is setuid root. This binary executes /opt/pia/openvpn-64/openvpn, passing the parameters provided from the command line. Care was taken to programmatically disable potentially dangerous openvpn parameters; however, the --route-pre-down parameter can be used. This parameter accepts an arbitrary path to a script/program to be executed when OpenVPN exits. The --script-security parameter also needs to be passed to allow for this action to be taken, and --script-security is not currently in the disabled parameter list. A local unprivileged user can pass a malicious script/binary to the --route-pre-down option, which will be executed as root when openvpn is stopped.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References