The guest operating system processes send informational messages to the ESX host through VMware Tools. If the amount of data the host stored as a result of these messages was unlimited, an unrestricted data flow would provide an opportunity for an attacker to stage a denial-of-service (DoS) attack.

The informational messages sent by guest operating processes are known as setinfo messages and typically contain name-value pairs that define virtual machine characteristics or identifiers that the host stores—for example, ipaddress=10.17.87.224. The configuration file containing these name-value pairs is limited to a size of 1MB, which prevents attackers from staging a DoS attack by writing software that mimics VMware Tools and filling the host's memory with arbitrary configuration data, which consumes space needed by the virtual machines.

If you require more than 1MB of storage for name-value pairs, you can change the value as required. You can also prevent the guest operating system processes from writing any name-value pairs to the configuration file.