This module uses an arbitrary file upload vulnerability, an authentication bypass (which depends on the target version) and a information disclosure vulnerability in order to upload and execute a WAR file in the Tomcat webapps folder. Since the Apache Tomcat server is running with root (SYSTEM in Windows targets) user, the deployed agent will run with the same privileges.
In dnsmasq before 2.78, if the DNS packet size does not match the expected size, the size parameter in a memset call gets a negative value. As it is an unsigned value, memset ends up writing up to 0xffffffff zero's (0xffffffffffffffff in 64 bit platforms), making dnsmasq crash.