Determining the likelihood of traffic being legitimately received at a proxy server in a cloud-based proxy service

• US 8,646,064 B1
• Filed: 10/31/2012
• Issued: 02/04/2014
• Est. Priority Date: 08/07/2012
• Status: Active Grant

• Current Assignee: CloudFlare Incorporated
• Original Assignee: CloudFlare Incorporated
• Inventors: Holloway, Lee Hahn, Rao, Srikanth N., Prince, Matthew Browning, Tourne, Matthieu Philippe Franois, Pye, Ian Gerald, Bejjani, Ray Raymond, Rodery, Terry Paul Jr.
• Primary Examiner(s): Abrishamkar, Kaveh
• Application Number:
  US13/665,807
• Publication Number:
  US 20140047539A1
• Time in Patent Office: 461 Days
• Field of Search: None
• US Class Current: 726/12
• CPC Class Codes: G06F 21/552 involving long-term monitoring or reporting
• CPC Class Codes: G06F 21/577 Assessing vulnerabilities and evaluating computer system security
• CPC Class Codes: H04L 63/0281 Proxies
• CPC Class Codes: H04L 63/1408 by monitoring network traffic monitoring network traffic per se H04L43/00
• CPC Class Codes: H04L 63/1416 Event detection, e.g. attack signature detection
• CPC Class Codes: H04L 63/1425 Traffic logging, e.g. anomaly detection
• CPC Class Codes: H04L 63/1433 Vulnerability analysis
• CPC Class Codes: H04L 63/1458 Denial of Service
• CPC Class Codes: H04L 63/1466 Active attacks involving interception, injection, modification, spoofing of data unit addresses, e.g. hijacking, packet injection or TCP sequence number attacks
• CPC Class Codes: H04L 63/20 for managing network security; network security policies in general filtering policies H04L63/0227

Abstract

Message(s) are received from each one of multiple proxy servers, which are anycasted to the same IP address, that indicate source IP addresses of packets that are received that are directed to that same IP address. These proxy servers receive the packets as result of domain(s) resolving to that same IP address, and a particular one of the proxy servers receives the packets as a result of an anycast protocol implementation selecting that proxy server. Based on these message(s) from each of the proxy servers, a determination of the likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers is determined A message is transmitted to each of the proxy servers that indicates which source IP addresses of packets are not likely to be legitimately received at that proxy server.

Claims

1. A method for determining a likelihood of a packet having a particular source address being received at a particular one of a plurality of proxy servers that are anycasted to a same IP address, wherein the proxy servers are part of a cloud-based proxy service and are situated between a plurality of client computing devices accessing network resources and a plurality of origin servers that serve network resources, the method comprising:

receiving, from each of the plurality of proxy servers, one or more messages that indicate source IP addresses of packets received at that proxy server that are directed to the same IP address, wherein the proxy servers receive traffic at the same IP address as a result of one or more domains resolving to the same IP address; and

wherein a particular one of the proxy servers receives packets directed to the same IP address as a result of an anycast protocol implementation selecting that particular one of the proxy servers as the closest in terms of routing protocol metric used to route traffic to the proxy servers;

determining, based on the one or more messages from each of the plurality of proxy servers, a likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers;

transmitting, to each of the proxy servers, a message that indicates which source IP addresses of packets are not likely to be legitimately received at that proxy server.

2. The method of claim 1, wherein the message transmitted to each of the proxy servers includes a set of rules to rate limit packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

3. The method of claim 1, wherein the message transmitted to each of the proxy servers includes a set of rules to block packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

4. The method of claim 1, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are likely to be legitimately received at that proxy server.

5. The method of claim 1, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are not likely to be legitimately received at that proxy server.

6. The method of claim 1, wherein the step of receiving from each of the plurality of proxy servers the one or more messages that indicate source IP addresses of packets received at that proxy server that are directed to the same IP address, occurs only when the same IP address is not believed to be currently under a denial of service (DoS) attack.

7. The method of claim 1, wherein the one or more messages received from each of the plurality of proxy servers further indicates a number of packets of each source IP address received at that proxy server.

8. The method of claim 1, wherein the one or more messages are received as a result of a client-side script that is inserted by the proxy servers into web pages of domains that resolve to the same IP address, wherein the client-side script, when executed, causes a packet to be transmitted to the same IP address.

9. The method of claim 1, further comprising:

responsive to a network event that affects the likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers, transmitting a message to the proxy servers that indicates a suspension of any rate limits that have been installed as a result of transmitting the messages to the proxy servers that indicate which source IP addresses of packets are not likely to be legitimately received at the proxy servers.

10. An apparatus, comprising:

a plurality of proxy servers that are anycasted to a same IP address, wherein each of the plurality of proxy servers is configured to perform the following;

receive packets at the same IP address as a result of one or more domains resolving to the same IP address, wherein this proxy server receives the packets at the same IP address as a result of an anycast protocol implementation selecting this one of the plurality of proxy servers as the closest in terms of routing protocol metric used to route traffic to the plurality of proxy servers;

transmit one or more messages to a central server that indicate source IP addresses of the received packets; and

receive, from the central server, a message that indicate source IP addresses of packets that are not likely to be legitimately received at that proxy server; and

install, based on the received message, one or more rules to rate limit packets that are received having a source IP address that is not likely to be legitimately received at that proxy server; and

the central server coupled with the plurality of proxy servers, wherein the central server is configured to perform the following;

receive, from each of the plurality of proxy servers, the one or more messages that indicate source IP addresses of the received packets;

determine, based on the one or more messages received from the plurality of proxy servers, a likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers; and

transmit, to each of the proxy servers, the message that indicates which source IP addresses of packets are not likely to be legitimately received at that proxy server.

11. The apparatus of claim 10, wherein the message transmitted to each of the proxy servers includes a set of rules to rate limit packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

12. The apparatus of claim 10, wherein the message transmitted to each of the proxy servers includes a set of rules to block packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

13. The apparatus of claim 10, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are likely to be legitimately received at that proxy server.

14. The apparatus of claim 10, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are not likely to be legitimately received at that proxy server.

15. The apparatus of claim 10, wherein the proxy servers are configured to transmit the one or more messages to the central server that indicate source IP addresses of the received packets only when the destination IP address of those packets is not believed to be currently under a denial of service (DoS) attack.

16. The apparatus of claim 10, wherein the one or more messages to be transmitted by each of the proxy servers further indicates a number of packets of each source IP address received at that proxy server.

17. The apparatus of claim 10, wherein the one or more messages to be transmitted by each of the proxy servers are to be transmitted as a result of a client-side script that is inserted by the proxy servers into web pages of domains that resolve to the same IP address, wherein the client-side script, when executed, causes a packet to be transmitted to the same IP address.

18. The apparatus of claim 10, further comprising:

responsive to a network event that affects the likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers, transmitting a message to the proxy servers that indicates a suspension of any rate limits that have been installed as a result of transmitting the messages to the proxy servers that indicate which source IP addresses of packets are not likely to be legitimately received at the proxy servers.

19. A non-transitory computer-readable storage medium that provides instructions that, if executed by a processor, will cause said processor to perform operations for determining a likelihood of a packet having a particular source address being received at a particular one of a plurality of proxy servers that are anycasted to a same IP address, wherein the proxy servers are part of a cloud-based proxy service and are situated between a plurality of client computing devices accessing network resources and a plurality of origin servers that serve network resources, the operations comprising:

receiving, from each of the plurality of proxy servers, one or more messages that indicate source IP addresses of packets received at that proxy server that are directed to the same IP address, wherein the proxy servers receive traffic at the same IP address as a result of one or more domains resolving to the same IP address; and

wherein a particular one of the proxy servers receives packets directed to the same IP address as a result of an anycast protocol implementation selecting that particular one of the proxy servers as the closest in terms of routing protocol metric used to route traffic to the proxy servers;

determining, based on the one or more messages from each of the plurality of proxy servers, a likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers;

transmitting, to each of the proxy servers, a message that indicates which source IP addresses of packets are not likely to be legitimately received at that proxy server.

20. The non-transitory computer-readable storage medium of claim 19, wherein the message transmitted to each of the proxy servers includes a set of rules to rate limit packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

21. The non-transitory computer-readable storage medium of claim 19, wherein the message transmitted to each of the proxy servers includes a set of rules to block packets received with source IP addresses that are not likely to be legitimately received by that proxy server.

22. The non-transitory computer-readable storage medium of claim 19, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are likely to be legitimately received at that proxy server.

23. The non-transitory computer-readable storage medium of claim 19, wherein the message transmitted to each of the proxy servers specifies the source IP addresses of packets that are not likely to be legitimately received at that proxy server.

24. The non-transitory computer-readable storage medium of claim 19, wherein the step of receiving from each of the plurality of proxy servers the one or more messages that indicate source IP addresses of packets received at that proxy server that are directed to the same IP address, occurs only when the same IP address is not believed to be currently under a denial of service (DoS) attack.

25. The non-transitory computer-readable storage medium of claim 19, wherein the one or more messages received from each of the plurality of proxy servers further indicates a number of packets of each source IP address received at that proxy server.

26. The non-transitory computer-readable storage medium of claim 19, wherein the one or more messages are received as a result of a client-side script that is inserted by the proxy servers into web pages of domains that resolve to the same IP address, wherein the client-side script, when executed, causes a packet to be transmitted to the same IP address.

27. The non-transitory computer-readable storage medium of claim 19, wherein the operations further comprise:

responsive to a network event that affects the likelihood of a packet having a particular source IP address being legitimately received at each of the proxy servers, transmitting a message to the proxy servers that indicates a suspension of any rate limits that have been installed as a result of transmitting the messages to the proxy servers that indicate which source IP addresses of packets are not likely to be legitimately received at the proxy servers.