The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 03, 2012
Filed:
Jun. 30, 2004
Mark Stuart Day, Milton, MA (US);
Mark Stuart Day, Milton, MA (US);
Cisco Technology, Inc., San Jose, CA (US);
Abstract
Presently disclosed are methods and apparatus for analyzing packets and packet flows to detect covert communications channels (including reverse tunnels) in real time. These systems actively probe a suspicious connection in ways that are not possible in prior art log-based techniques and may initiate countermeasures against discovered covert channels. The present system may be implemented in a network device, such as an intrusion detection system, content engine, or other intermediary device employing a web cache. Embodiments automatically detect suspicious activity at particular source addresses by using relatively simple tests to detect suspect packets that should receive more extensive scrutiny. After more rigorous secondary testing (optionally including active probing techniques), suspect packets are either returned to the occasionally-checked state or flagged for further action, such as raising an alert or taking automatic countermeasures against the covert channel or its originators.