Blocking intrusion attacks at an offending host

1. A method of protecting a network from intrusions, the method comprising:

receiving a blocking instruction and at least a portion of an offending packet at a host coupled to a protected network, wherein the host comprises a server computer upon which is executed an operating system and at least one application that originates the offending packet, wherein the offending packet is of the type associated with an intrusion attack, and wherein the host is an offending host;

verifying that the offending packet originated from the host; and

in response to the verification of the offending packet originating from the host, initiating an intrusion protection operation on the host thereby inhibiting origination of a subsequent outbound offending packet by the application executed upon the host.

2. The method of claim 1 wherein the host comprises:

a first host configured as a proxy; and

a second host originating the offending packet and transmitting the offending packet through the proxy,

wherein the blocking instruction is received at the proxy.

3. The method of claim 2 wherein the proxy transmits the blocking instruction to the second host.

4. The method of claim 1 wherein verifying further comprises:

comparing corresponding media access control (MAC) addresses associated with the offending packet and the offending host.

5. The method of claim 1 wherein verifying further comprises:

comparing source and destination Internet Protocol (IP) addresses associated with the offending packet and the offending host.

6. The method of claim 1 wherein verifying further comprises:

checking Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) source and destination ports associated with the first offending packet and the offending host.

7. The method of claim 1 wherein the offending packet is a Transmission Control Protocol (TCP) packet and verifying further comprises:

checking sequence numbers associated with the offending packet and the offending host.

8. The method of claim 1 wherein inhibiting origination further comprises:

returning the subsequent outbound offending packet to an offending application, wherein the offending packet and subsequent outbound offending packet originated from the offending application; and

ending a connection with the offending application.

9. The method of claim 1 wherein the at least a portion of the offending packet is encapsulated into a User Datagram Protocol (UDP) packet and is returned to the offending host as a notification packet.

10. The method of claim 9 wherein the intrusion protection operation comprises, at the offending host:

identifying an offending application on the offending host that originated the offending packet; and

terminating the offending application.

11. The method of claim 1 wherein the intrusion protection operation comprises, at the offending host:

posting an event or error message for an operator of the offending host.

12. The method of claim 1 wherein the intrusion protection operation comprises:

accessing an intrusion policy on the offending host.

13. The method of claim 1 wherein the blocking instruction is an Internet Control Message Protocol (ICMP) message.

14. An apparatus comprising:

a processor; and

program code configured to be executed by the processor to protect a network from intrusions at a host coupled to a protected network, wherein the host comprises a server computer upon which is executed an operating system and at least one application that originates an offending packet, wherein the offending packet is of the type associated with an intrusion attack, the program code resident in a memory and configured to receive a blocking instruction and a portion of the offending packet, verify that the offending packet originated from the host, and in response to the verification of the offending packet originating from the host, initiate an intrusion protection operation on the host thereby inhibiting origination of a subsequent outbound offending packet by the application executed upon the host, wherein the host is an offending host.

15. The apparatus of claim 14 wherein the server computer is a first computer configured as a proxy, the apparatus further comprising:

a second computer having a second memory; and

second program code of an offending application, the second program code resident in the second memory of the second computer and configured to originate the offending packet and transmit the offending packet through the proxy,

wherein the blocking instruction is received at the proxy.

16. The apparatus of claim 15 wherein the proxy is further configured to transmit the blocking instruction to the second computer.

17. A program product, comprising:

a non-transitory computer readable medium; and

program code configured to protect a network from intrusions at a host coupled to a protected network, wherein the host comprises a server computer upon which is executed an operating system and at least one application that originates an offending packet, wherein the offending packet is of the type associated with an intrusion attack, the program code resident on the computer readable medium and configured to receive a blocking instruction and a portion of the offending packet, verify that the offending packet originated from the host, and in response to the verification of the offending packet originating from the host, initiate an intrusion protection operation on the host thereby inhibiting origination of a subsequent outbound offending packet by the application executed upon the host, wherein the host is an offending host.