Threat detection using a time-based cache of reputation information on an enterprise endpoint

• US 10,382,459 B2
• Filed: 05/02/2018
• Issued: 08/13/2019
• Est. Priority Date: 09/14/2014
• Status: Active Grant

• Current Assignee: Sophos Limited (Sophos Group Ltd.)
• Original Assignee: Sophos Limited (Sophos Group Ltd.)
• Inventors: Harris, Mark D., Reed, Simon Neil, Ray, Kenneth D., Watkiss, Neil Robert Tyndale, Thomas, Andrew J., Cook, Robert W.
• Primary Examiner(s): Steinle, Andrew J
• Application Number:
  US15/969,725
• Publication Number:
  US 20180278631A1
• Time in Patent Office: 468 Days
• Field of Search: None
• CPC Class Codes: H04L 63/102 Entity profiles
• CPC Class Codes: H04L 63/107 wherein the security policies are location-dependent, e.g. entities privileges depend on current location or allowing specific operations only from locally connected terminals
• CPC Class Codes: H04L 63/108 when the policy decisions are valid for a limited amount of time
• CPC Class Codes: H04L 63/1416 Event detection, e.g. attack signature detection
• CPC Class Codes: H04L 63/1433 Vulnerability analysis

Abstract

Threat detection instrumentation is simplified by providing and updating labels for computing objects in a context-sensitive manner. This may include simple labeling schemes to distinguish between objects, e.g., trusted/untrusted processes or corporate/private data. This may also include more granular labeling schemes such as a three-tiered scheme that identifies a category (e.g., financial, e-mail, game), static threat detection attributes (e.g., signatures, hashes, API calls), and explicit identification (e.g., what a file or process calls itself). By tracking such data for various computing objects and correlating these labels to malware occurrences, rules can be written for distribution to endpoints to facilitate threat detection based on, e.g., interactions of labeled objects, changes to object labels, and so forth. In this manner, threat detection based on complex interactions of computing objects can be characterized in a platform independent manner and pre-processed on endpoints without requiring significant communications overhead with a remote threat management facility.

Claims

1. A method comprising:

detecting an action at an endpoint;

receiving, from a threat management facility on the endpoint, a reputation score for the action and a time to live for the action, the reputation score based on a description of the action including a process, executing on the endpoint, that took the action and an object programmatically associated with the process through the action;

caching the description and the reputation score in an event cache on the endpoint for a duration equal to the time to live;

accumulating a plurality of the descriptions and reputation scores that have not expired in the event cache;

expiring at least one of the descriptions and reputation scores by removing the at least one of the descriptions and reputation scores from the event cache after the time to live;

generating a threat detection when a pattern of the descriptions and reputation scores in the event cache indicate malicious software operating on the endpoint; and

communicating the threat detection to an analysis facility external to the endpoint.

2. The method of claim 1, wherein the endpoint is within an enterprise network, and the analysis facility is external to the enterprise network.

3. The method of claim 1, wherein the object is programmatically associated with the process through the action by at least one of triggering the action, being acted upon by the action, receiving data from the action, or providing data to the action.

4. The method of claim 1, wherein the object includes a URL accessed by the action.

5. The method of claim 1, wherein the object includes a filename accessed by the action.

6. The method of claim 1, further comprising taking a remedial action at the endpoint when malicious activity is detected.

7. The method of claim 1, wherein the reputation score is based on a geographical distribution of the description on a plurality of endpoints.

8. The method of claim 1, wherein the reputation score is based on a number of prior occurrences of the description on a plurality of endpoints.

9. A computer program product comprising non-transitory computer executable code embodied in a non-transitory computer readable medium that, when executing on one or more computing devices, performs the steps of:

detecting an action at an endpoint;

receiving, from a threat management facility on the endpoint, a reputation score for the action and a time to live for the action, the reputation score based on a description of the action including a process, executing on the endpoint, that took the action and an object programmatically associated with the process through the action;

caching the description and the reputation score in an event cache on the endpoint for a duration equal to the time to live;

accumulating a plurality of the descriptions and reputation scores that have not expired in the event cache;

expiring at least one of the descriptions and reputation scores by removing the at least one of the descriptions and reputation scores from the event cache after the time to live;

generating a threat detection when a pattern of the descriptions and reputation scores in the event cache indicate malicious software operating on the endpoint; and

communicating the threat detection to an analysis facility external to the endpoint.

10. The computer program product of claim 9, wherein the object is programmatically associated with the process through the action by at least one of triggering the action, being acted upon by the action, receiving data from the action, or providing data to the action.

11. The computer program product of claim 9, wherein the object includes a URL accessed by the action.

12. The computer program product of claim 9, wherein the object includes a filename accessed by the action.

13. The computer program product of claim 9, wherein the code further performs the step of taking a remedial action at the endpoint when malicious activity is detected.

14. The computer program product of claim 9, wherein the reputation score is based on a geographical distribution of the description on a plurality of endpoints.

15. The computer program product of claim 9, wherein the reputation score is based on a number of prior occurrences of the description on a plurality of endpoints.

16. A system comprising:

a threat management facility configured to manage threats to an enterprise; and

an endpoint of the enterprise having a memory and a processor, the memory storing an object, a process, and a threat management facility, and the processor configured to detect an action at the endpoint, to receive from the threat management facility a reputation score for the action and a time to live for the action, the reputation score based on a description of the action including a process and an object programmatically associated with the process through the action, to cache the description and the reputation score in an event cache on the endpoint for a duration equal to the time to live, to accumulate a plurality of the descriptions and reputation scores that have not expired in the event cache, to expire at least one of the descriptions and reputation scores by removing the at least one of the descriptions and reputation scores from the event cache after the time to live, to generate a threat detection for communication to an analysis facility external to the endpoint when a pattern of the descriptions and reputation scores in the event cache indicate malicious software operating on the endpoint.

17. The system of claim 16, wherein the object is programmatically associated with the process through the action by at least one of triggering the action, being acted upon by the action, receiving data from the action, or providing data to the action.

18. The system of claim 16, wherein the object includes at least one of a URL and a filename accessed by the action.

19. The system of claim 16, wherein the reputation score is based on a geographical distribution of the description on a plurality of endpoints.

20. The system of claim 16, wherein the reputation score is based on a number of prior occurrences of the description on a plurality of endpoints.