SECURING CUSTOMER VIRTUAL MACHINES IN A MULTI-TENANT CLOUD

• US 20110302415A1
• Filed: 03/10/2011
• Published: 12/08/2011
• Est. Priority Date: 06/02/2010
• Status: Active Grant

• Current Assignee: Vmware LLC (Broadcom, Inc.)
• Original Assignee: VMware, Inc. (Broadcom, Inc.)
• Inventors: AHMAD, Irfan, GUNTI, Mukund, CHATURVEDI, Abhishek, KIRIANSKY, Vladimir
• Granted Patent: US 8,909,928 B2
• Time in Patent Office: Days
• US Class Current: 713/168
• CPC Class Codes: G06F 21/51 at application loading time, e.g. accepting, rejecting, starting or inhibiting executable software based on integrity or source reliability
• CPC Class Codes: G06F 21/57 Certifying or maintaining trusted computer platforms, e.g. secure boots or power-downs, version controls, system software checks, secure updates or assessing vulnerabilities
• CPC Class Codes: G06F 21/575 Secure boot
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/08 for authentication of entities cryptographic mechanisms or cryptographic arrangements for entity authentication H04L9/32
• CPC Class Codes: H04L 9/08 Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords network architectures or network communication protocols for supporting key management in a packet data network H04L63/06
• CPC Class Codes: H04L 9/0825 using asymmetric-key encryption or public key infrastructure [PKI], e.g. key signature or public key certificates
• CPC Class Codes: H04L 9/083 involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]
• CPC Class Codes: H04L 9/0897 involving additional devices, e.g. trusted platform module [TPM], smartcard or USB

Abstract

A trusted virtualization platform protects sensitive customer data during operation of virtual machines in a multi-tenant cloud computing center. The trusted virtualization platform limits administrator access to the data and state of the virtual machines running thereon, reports any changes made thereto, and requires keys provided by the customer or a trusted third party of the customer to perform management operations on the virtual machines. By requiring cloud computing centers to use such trusted virtualization platforms, customers uploading their virtual machines into the cloud computing center can be assured that cloud administrators will not be able to access or tamper with their private data. Furthermore, customers can directly audit all important state or configuration changes for their virtual machines as the trusted virtualization platform can be configured to report all such changes according to a security policy set by the customer.

Claims

1. A method of securing virtual machines in a multi-tenant data center including a plurality of server computers and persistent data stores, comprising:

configuring a server computer with an attestation module;

installing a software stack on the server computer;

measuring, with the attestation module, a static property of the software stack and storing the measurement;

transmitting the measurement to an external entity and, in response thereto, receiving from the external entity a key for running a virtual machine on top of the software stack; and

running the virtual machine on top of the software stack using the key.

2. The method of claim 1, wherein the external entity is an owner of the virtual machine or a third party to whom the owner has delegated security monitoring responsibilities.

3. The method of claim 1, wherein the software stack does not permit selected management operations to be performed on the virtual machine without permission from the external entity.

4. The method of claim 3, wherein the selected management operations include migration of the virtual machine to another server computer, creation of a snapshot of the virtual machine, and in-place upgrade of the virtual machine.

5. The method of claim 1, further comprising:

storing a virtual disk of the virtual machine in a persistent data store in encrypted form;

and receiving a key for decrypting the virtual disk from the external entity.

6. The method of claim 1, wherein the software stack prevents the virtual machine from communicating with an identified virtual machine running on another sever computer without an encryption key.

7. The method of claim 6, further comprising:

transmitting a request for the encryption key to the external entity, the request including an identification of the virtual machine running on another sever computer.

8. The method of claim 1, wherein the software stack has multiple layers and a static property measurement is carried out incrementally each time a software layer is added.

9. The method of claim 8, wherein the TPM has multiple registers and each incremental static property measurement is recorded in one of the registers of the TPM.

10. A non-transitory machine readable storage medium for securing virtual machines in a multi-tenant data center including a plurality of server computers and persistent data stores, the machine readable storage medium having computer instructions encoded thereon causing a computer configured as a trusted virtualization platform to perform a method, the method comprising:

receiving a request for a key to run a virtual machine on a server computer configured with an attestation module, the key request including a customer ID associated with the virtual machine;

requesting the server computer for static property measurements of a software stack on top which the virtual machine will be run and, in response thereto, receiving the static property measurements; and

confirming from the static property measurements that the software stack is a trusted software stack and, after said confirming, transmitting to the server computer the key to run the virtual machine on the server computer.

11. The machine readable storage medium of 10, wherein the method further comprises:

receiving a public key of the attestation module from the server computer; and

searching for the public key in an inventory associated with the multi-tenant data center,

wherein the key to run the virtual machine on the server computer is transmitted to the server computer after it is confirmed that the public key has been found in the inventory of associated with the multi-tenant data center.

12. The machine readable storage medium of 10, wherein the method further comprises:

receiving a request to perform an operation on the virtual machine running on the server computer; and

examining a policy associated with the virtual machine and transmitting a key for performing the operation on the virtual machine if the policy permits the operation and transmitting a message denying the request if the policy does not permit the operation.

13. The machine readable storage medium of 12, wherein each of the keys has an associated lease period, after the expiration of which the key is no longer valid.

14. The machine readable storage medium of 10, wherein the method further comprises:

receiving and recording a report of operations performed on the virtual machine.

15. The machine readable storage medium of 10, wherein the method further comprises:

after the virtual machine is running on the server computer, transmitting a key for encrypting and decrypting data stored in a virtual disk of the virtual machine.

16. The machine readable storage medium of 10, wherein the method further comprises:

receiving a request to transmit a network packet to another virtual machine running in a different server computer;

confirming that the different server computer is running a trusted software stack and said another virtual machine is running on top of the trusted software stack; and

upon said confirming, transmitting to the server computer a key for encrypting the network packet to be transmitted to said another virtual machine.

17. The machine readable storage medium of 10, wherein the method further comprises:

receiving a public portion of an attestation identification key (AIK) from the server computer,

wherein the static property measurements are encrypted with a private portion of the AIK and decrypted using the public portion of the AIK.

18. The machine readable storage medium of 10, wherein the method further comprises:

transmitting a random nonce to the server computer; and

confirming that the static property measurements were actually transmitted by the server computer when the random nonce is also received from the server computer.

19. A multi-tenant data center comprising:

a plurality of server computers, each of which is configured with a trusted platform module and a trusted virtualization platform having one or more software layers on top of which a customer application is to be executed; and

a persistent storage system coupled to the server computers, in which files for launching the customer application are stored, the files including an encrypted portion and a plain text portion that identifies the customer and a network location associated with the customer,

wherein the trusted virtualization platform is programmed to;

(i) report any changes to the trusted virtualization platform to the network location associated with the customer;

(ii) obtain keys from the network location associated with the customer to decrypt the encrypted portion of the files for launching the customer application; and

(iii) prohibit direct inspection of memory of the virtual machine.

20. The system of claim 19, wherein the keys are stored in the memory of the virtual machine and are inaccessible by an administrator.

21. The system of claim 20, wherein the keys are not stored persistently by the server computer.

22. The system of claim 19, wherein at least one of the keys has a lease period.

23. The system of claim 19, wherein the application is an instance of a virtual machine, and the files include a configuration file for the virtual machine and a virtual disk of the virtual machine.