Detecting anomalous web proxy activity

• US 8,117,655 B2
• Filed: 12/14/2009
• Issued: 02/14/2012
• Est. Priority Date: 12/13/2005
• Status: Active Grant

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Intellectual Property II LP (AT&T, Inc.)
• Inventors: Spielman, Chaim
• Primary Examiner(s): LAFORGIA, CHRISTIAN A
• Application Number:
  US12/637,213
• Publication Number:
  US 20110093944A1
• Time in Patent Office: 792 Days
• Field of Search: 726 22- 25
• US Class Current: 726/22
• CPC Class Codes: G06F 2221/2101 Auditing as a secondary aspect
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 63/0227 Filtering policies mail message filtering H04L51/212
• 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

Abstract

A method, system and apparatus for detecting anomalous web proxy activity by end-users are disclosed. The techniques include analyzing records from a web proxy log and determining whether the records contain anomalous end-user activity by inspecting a uniform resource locator and a connect instruction included therein. The techniques also include generating an alert in response to the analysis.

Claims

1. A method of detecting anomalous web proxy activity comprising:

filtering a plurality of records from a proxy log by a detection module to exclude records that do not include identified information, the plurality of records representing proxy connections made by a proxy server, the records including connection-specific transaction information comprising one or more of a source internet protocol address, a destination internet protocol address and a uniform resource locator field, the identified information comprising an internet protocol address at a beginning of the uniform resource locator field of the plurality of records;

calculating a number of distinct destination internet protocol addresses to which a source internet protocol address is connected from the plurality of records not excluded by the filtering;

comparing the calculated number of distinct destination internet protocol addresses to a threshold number established for the source internet protocol address; and

determining, based on the comparing, whether a first one of the records extracted from the web proxy log, and not excluded by the filtering, comprises suspicious web activity.

2. The method of claim 1, wherein filtering the plurality of records comprises filtering the plurality of records to exclude records that do not include a connect instruction.

3. The method of claim 1, further comprising parsing the record by comparing a time entry of the record to a configurable time period.

4. The method of claim 2, wherein the connect instruction is a hyper text transfer protocol connect method.

5. The method of claim 1, further comprising parsing the uniform resource locator field for the destination internet protocol address.

6. The method of claim 1, further comprising generating an alert based on the comparison.

7. A non-transitory computer-readable medium storing computer-readable instructions that, when executed by a computing device, cause the computing device to:

filter a plurality of records from a proxy log to exclude records that do not include identified information, the plurality of records representing proxy connections made by a proxy server, the records including connection-specific transaction information comprising one or more of a source internet protocol address, a destination internet protocol address and a uniform resource locator field, the identified information comprising an internet protocol address at a beginning of the uniform resource locator field of the plurality of records;

calculate a number of distinct destination internet protocol addresses to which a source internet protocol address is connected from the plurality of records not excluded by the filtering;

compare the calculated number of distinct destination internet protocol addresses to a threshold number associated with the source internet protocol address; and

determine whether a first one of the records extracted from the web proxy log, and not excluded by the filtering, comprises suspicious web activity based on the comparison.

8. The non-transitory computer-readable medium of claim 7, further comprising instructions that cause the computing device to compare a time entry of the record to a configurable time period.

9. The non-transitory computer-readable medium of claim 7, further comprising instructions that, when executed by the machine, cause the computing device to parse the numeric uniform resource locator field for the Internet Protocol address.

10. The non-transitory computer-readable medium of claim 7, including instructions that, when executed by the computing device, cause the computing device to filter the plurality of records to exclude records that do not include a connect instruction.

11. The non-transitory computer-readable medium of claim 7, further comprising instructions that, when executed by the computing device, cause the computing device to generate an alert based on the comparison.

12. The non-transitory computer-readable medium of claim 11, further comprising instructions that, when executed by the computing device, cause the computing device to transmit the alert to a system administrator.

13. A system comprising:

a service delivery device coupled to a network, the service delivery device including a processor and memory storing instructions that, in response to receiving a request for access to a service, cause the processor to;

filter a plurality of records from a proxy log to exclude records that do not include identified information, the plurality of records representing proxy connections made by a proxy server, the records including connection-specific transaction information comprising one or more of a source internet protocol address, a destination internet protocol address and a uniform resource locator field, the identified information comprising an internet protocol address at a beginning of the uniform resource locator field of the plurality of records;

calculate a number of distinct destination internet protocol addresses to which a source internet protocol address is connected;

compare the number of distinct destination internet protocol addresses to a threshold number established for the source internet protocol address; and

determine whether a first one of the records extracted from the web proxy log, and not excluded by the filtering, comprises suspicious web activity based on the comparison.

14. The system of claim 13, wherein the memory stores instructions that, in response to receiving the request for access to a service, further cause the processor to filter the plurality of records to exclude records that do not include a connect instruction.

15. The system of claim 13, wherein the memory stores instructions that, in response to receiving the request for access to a service, further cause the processor to compare a time entry of the record to a configurable time period.

16. The system of claim 13, wherein the memory stores instructions that, in response to receiving the request for access to a service, further cause the processor to parse the numeric uniform resource locator for the Internet Protocol address.

17. The system of claim 13, wherein the memory stores instructions that, in response to receiving the request for access to a service, further cause the processor to generate the alert based on the comparison.