Selection of a countermeasure

1. A network system comprising:

an attack analyzer to:

assign a metric of vulnerability to a first virtual machine, the metric of vulnerability indicating a likelihood of attack on the first virtual machine, and the metric of vulnerability assigned based on connections of the first virtual machine to other virtual machines,

in response to the metric of vulnerability, cause the first virtual machine to enter a detection phase,

receive an alert corresponding to the first virtual machine, the alert generated responsive to monitoring performed by the detection phase, and

select a countermeasure based on the received alert; and

a network controller to:

implement the selected countermeasure.

2. The network system of claim 1 further comprising:

a detection engine to:

monitor traffic in and out of the first virtual machine during the detection phase; and

generate the alert indicating a type of vulnerability of the first virtual machine.

3. The network system of claim 2 wherein:

the network controller is further to initiate the detection engine to scan the first virtual machine for vulnerability information; and

the attack analyzer is further to receive the vulnerability information to assign the metric of vulnerability.

4. The network system of claim 1 further comprising:

a network switch to reconfigure the network system by isolating the first virtual machine, wherein the selected countermeasure comprises programming the network switch to isolate the first virtual machine.

5. The network system of claim 1 , wherein the attack analyzer is to cause the first virtual machine to enter the detection phase in response to the metric of vulnerability reaching a specified threshold.

6. The network system of claim 1 , wherein the alert indicates a type of vulnerability of a plurality of types of vulnerabilities, and the attack analyzer is to:

select a first type of countermeasure in response to the alert indicating a first type of vulnerability corresponding to the first virtual machine; and

select a second, different type of countermeasure in response to the alert indicating a second, different type of vulnerability corresponding to the first virtual machine.

7. The network system of claim 6 , wherein the first type of countermeasure comprises one of diverting traffic away from the first virtual machine, filtering packets of the first virtual machine, modifying an address of packets of the first virtual machine, and blocking a port associated with the first virtual machine, and

the second type of countermeasure comprises programming a network switch to isolate the first virtual machine.

8. The network system of claim 1 , wherein the selecting of the countermeasure comprises:

calculating a benefit of each respective countermeasure of a plurality of countermeasures;

selecting a countermeasure from the plurality of countermeasures based on the calculated benefits of the plurality of countermeasures.

9. The network system of claim 1 , wherein the attack analyzer is to change the metric of vulnerability assigned to the first virtual machine in response to the selected countermeasure.

10. A non-transitory machine-readable storage medium encoded with instructions that when executed cause a system to:

determine a metric of vulnerability corresponding to a first virtual machine, the metric of vulnerability being a likelihood of attack on the first virtual machine, and the metric of vulnerability determined based on connections of the first virtual machine to other virtual machines;

place the first virtual machine into a detection phase in response to the metric of vulnerability;

receive an alert indicating a type of vulnerability on the first virtual machine, the alert generated responsive to monitoring of traffic into and out of the first virtual machine during the detection phase; and

select a countermeasure based on the alert.

11. The non-transitory machine-readable storage medium of claim 10 , wherein the selecting of the countermeasure comprises:

determining a preferred countermeasure based on a benefit of the selected countermeasure to the first virtual machine, wherein the benefit of the selected countermeasure to the first virtual machine is based on a cost of the selected countermeasure and an intrusiveness of the selected countermeasure on the first virtual machine.

12. The non-transitory machine-readable storage medium of claim 10 , wherein the selecting of the countermeasure comprises:

receive multiple alerts, each alert of the multiple alerts corresponding to a different virtual machine; and

determine a correlation between the multiple alerts for predicting a path of an attack among multiple virtual machines.

13. The non-transitory machine-readable storage medium of claim 10 , wherein the selecting of the countermeasure comprises:

reconfiguring a network system by manipulating traffic flow to and from the first virtual machine through a network switch.

14. The non-transitory machine-readable storage medium of claim 10 , wherein the selecting of the countermeasure comprises:

selecting a first type of countermeasure in response to the alert indicating a first type of vulnerability corresponding to the first virtual machine; and

selecting a second, different type of countermeasure in response to the alert indicating a second, different type of vulnerability corresponding to the first virtual machine.

15. A method comprising:

assigning, by a system including a processor, a metric of vulnerability to a first virtual machine, the metric of vulnerability assigned based on connections of the first virtual machine to other virtual machines;

placing, by the system, the first virtual machine into a detection phase based on the metric of vulnerability;

receiving, by the system, an alert corresponding to the first virtual machine, the alert generated responsive to monitoring of the first virtual machine performed by the detection phase; and

selecting, by the system, a countermeasure based on the received alert; and

implementing, by the system, the selected countermeasure.

16. The method of claim 15 further comprising:

determining a benefit of the selected countermeasure based on the assigned metric of vulnerability to the first virtual machine.

17. The method of claim 15 wherein placing the first virtual machine into the detection phase comprises:

analyzing traffic in and out of the first virtual machine; and

determining whether the first virtual machine is compromised.

18. The method of claim 15 further comprising:

reassigning a metric of vulnerability to the virtual machine based on the selected countermeasure.

19. The method of claim 15 wherein assigning the metric of vulnerability to the first virtual machine comprises:

calculating a probability of an attack on the first virtual machine.

20. The non-transitory machine-readable storage medium of claim 14 , wherein the first type of countermeasure comprises one of diverting traffic away from the first virtual machine, filtering packets of the first virtual machine, modifying an address of packets of the first virtual machine, and blocking a port associated with the first virtual machine, and

the second type of countermeasure comprises programming a network switch to isolate the first virtual machine.