vSphere UI must limit the maximum size of a POST request.

The "maxPostSize" value is the maximum size in bytes of the POST which will be handled by the container FORM URL parameter parsing. Limit its size to reduce exposure to a denial-of-service attack.

If "maxPostSize" is not set, the default value of 2097152 (2MB) is used. The vSphere UI is configured in its shipping state to not set a value for "maxPostSize".

At the command prompt, run the following command:

# xmllint --xpath '/Server/Service/Connector[@port="${http.port}"]/@maxPostSize' /usr/lib/vmware-vsphere-ui/server/conf/server.xml 

Expected result:

XPath set is empty

If the output does not match the expected result, this is a finding.

Navigate to and open:

/usr/lib/vmware-vsphere-ui/server/conf/server.xml

Navigate to each of the <Connector> nodes.

Remove any configuration for "maxPostSize".

Restart the service with the following command:

# vmon-cli --restart vsphere-ui