Threat detection using URL cache hits
View Patent ↗Threat detection is improved by monitoring variations in observable events and correlating these variations to malicious activity. The disclosed techniques can be usefully employed with any attribute or other metric that can be instrumented on an endpoint and tracked over time including observable events such as changes to files, data, software configurations, operating systems, and so forth. Correlations may be based on historical data for a particular machine, or a group of machines such as similarly configured endpoints. Similar inferences of malicious activity can be based on the nature of a variation, including specific patterns of variation known to be associated with malware and any other unexpected patterns that deviate from normal behavior. Embodiments described herein use variations in, e.g., server software updates or URL cache hits on an endpoint, but the techniques are more generally applicable to any endpoint attribute that varies in a manner correlated with malicious activity.
1. A method comprising:
maintaining a uniform resource locator (URL) cache on each of a plurality of devices, the URL cache including a reputation score and a time to live for each of a plurality of URLs;
updating the URL cache on each of the plurality of devices using reputation scores from a remote threat management facility to add new entries for new URL traffic to the URL cache and using the time to live to expire existing entries from the URL cache;
monitoring the URL cache of each one of the plurality of devices with the remote threat management facility to detect a variance in one of the URL caches relative to each other one of the URL caches;
triggering an indication of compromise based on the variance; and
initiating a remedial action for the device storing the one of the URL caches in response to the indication of compromise.
2. The method of claim 1 wherein the variance includes a deviation in size of the one of the URL caches.
3. The method of claim 1 wherein the variance includes a deviation in average reputation.
4. The method of claim 1 wherein the variance includes a deviation in average time to live.
5. The method of claim 1 wherein the variance includes a presence of one or more unique URLs.
6. The method of claim 1 wherein the reputation score depends on popularity.
7. The method of claim 1 wherein the reputation score depends on frequency of requests.
8. The method of claim 1 wherein the reputation score depends on historically determined trust.
9. The method of claim 1 wherein the time to live depends on reputation.
10. The method of claim 1 wherein at least one of the plurality of devices includes a web server.
11. The method of claim 1 wherein at least one of the plurality of devices includes an endpoint.
12. The method of claim 1 wherein at least one of the plurality of devices includes a mobile device.
13. 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:
maintaining a uniform resource locator (URL) cache on each of a plurality of devices, the URL cache including a reputation score and a time to live for each of a plurality of URLs;
updating the URL cache on each of the plurality of devices using reputation scores from a remote threat management facility to add new entries for new URL traffic to the URL cache and using the time to live to expire existing entries from the URL cache;
monitoring the URL cache of each one of the plurality of devices with the remote threat management facility to detect a variance in one of the URL caches relative to each other one of the URL caches;
triggering an indication of compromise based on the variance; and
initiating a remedial action for the device storing the one of the URL caches in response to the indication of compromise.
14. The computer program product of claim 13 wherein the variance includes a deviation in size of the one of the URL caches.
15. The computer program product of claim 13 wherein the variance includes a deviation in average reputation.
16. The computer program product of claim 13 wherein the variance includes a deviation in average time to live.
17. The computer program product of claim 13 wherein the variance includes a presence of one or more unique URLs.
18. A system comprising:
a remote threat management facility configured to manage threats to an enterprise; and
a plurality of devices associated with the enterprise, each of the plurality of devices having a memory and a processor, the memory storing a uniform resource locator (URL) cache including a reputation score and a time to live for each of a plurality of URLs, and the processor configured to update the URL cache on each of the plurality of devices using reputation scores from the remote threat management facility to add new entries for new URL traffic to the URL cache and using the time to live to expire existing entries from the URL cache;
wherein the remote threat management facility is further configured to monitor the URL cache of each one of the plurality of devices to detect a variance in one of the URL caches relative to each other one of the URL caches, to generate an indication of compromise based on the variance, and to initiate a remedial action for the device storing the one of the URL caches based on the indication of compromise.
19. The system of claim 18 wherein the plurality of devices include a plurality of servers including one or more of a database server, a file server, a mail server, a print server, a web server, a gaming server, and an application server.
20. The system of claim 18 wherein the plurality of devices include a plurality of virtual servers instantiated on a virtual computing platform.