Ironport Systems, Inc.

Jeffrey Wescott

Daniel A Quinlan

Jason Kehl

In one embodiment, detecting unwanted electronic mail messages based on probabilistic analysis of referenced resources comprises receiving a whitelist and a blocklist each having a plurality of network resource identifiers that have appeared in prior messages; retrieving a particular network resource identifier; generating a list of properties for the particular network resource identifier; training a probabilistic filter using the properties; and repeating the retrieving, generating and training for all the network resource identifiers in the whitelist and blocklist. Thereafter, when an electronic mail message is received and contains a URL or other network resource identifier, a spam score or threat score can be generated for the message by testing properties of the network resource identifier using the trained probabilistic filter.

Detecting unwanted electronic mail messages based on probabilistic analysis of referenced resources

In one embodiment, a method comprises computer-implemented steps of receiving a plurality of electronic mail messages containing sender address information that is non-trusted. For each electronic mail message, information about the message is stored, and one or more receiving node identifiers in association with respective connected node identifiers is created, wherein the receiving node identifier identifies receiving mail server that received the particular message and the connected node identifier identifies a connected mail server that directly connected to the receiving node identifier to send the particular message directly to the receiving mail server. For each electronic mail message a receiving node identifier that has a largest number of connected node identifiers associated therewith is selected, and a connected node identifier that is associated with the one particular receiving node identifier that sent the particular message to the associated receiving node is selected and stored.

Growing community of inventors

San Bruno, CA, United States of America

Jeffrey Wescott