On Asterisk, prior to versions 18.24.2, 20.9.2, and 21.4.2 and certified-asterisk versions 18.9-cert11 and 20.7-cert2, an AMI user with write=originate may change all configuration files in the /etc/asterisk/ directory. Writing a new extension can be created which performs a system command to achieve RCE as the asterisk service user (typically...