The following features of can present security problems:

• Enabling 3D graphics using the Guest Additions exposes the host to additional security risks. See Hardware 3D Acceleration (OpenGL and Direct3D 8/9).

• When teleporting a machine, the data stream through which the machine's memory contents are transferred from one host to another is not encrypted. A third party with access to the network through which the data is transferred could therefore intercept that data. An SSH tunnel could be used to secure the connection between the two hosts. But when considering teleporting a VM over an untrusted network the first question to answer is how both VMs can securely access the same virtual disk image with a reasonable performance.

  If the network is not sufficiently trusted, the password should be changed for each teleportation as a third party could detect the unecrypted password hash when it is transferred between the target and source host machines.

• When Page Fusion, is enabled, it is possible that a side-channel opens up that enables a malicious guest to determine the address space of another VM running on the same host layout. For example, where DLLs are typically loaded. This information leak in itself is harmless, however the malicious guest may use it to optimize attack against that VM through unrelated attack vectors. It is recommended to only enable Page Fusion if you do not think this is a concern in your setup.

• When using the web service to control an host remotely, connections to the web service, over which the API calls are transferred using SOAP XML, are not encrypted. They use plain HTTP by default. This is a potential security risk. For details about the web service, see .

  The web services are not started by default. See to find out how to start this service and how to enable SSL/TLS support. It has to be started as a regular user and only the VMs of that user can be controlled. By default, the service binds to localhost preventing any remote connection.

• Traffic sent over a UDP Tunnel network attachment is not encrypted. You can either encrypt it on the host network level, with IPsec, or use encrypted protocols in the guest network, such as SSH. The security properties are similar to bridged Ethernet.

• Because of shortcomings in older Windows versions, using on Windows versions older than Vista with Service Pack 1 is not recommended.