Friday, September 12, 2008

Mail Scanning Techniques

As spammers become more sophisticated, mail scanning techniques grow in their importance.

1.Virus Scanning

The most basic level of mail scanning is virus scanning. The Barracuda Spam Firewall scans all email messages and all incoming files for viruses using three layers of virus scanning technology and automatically decompresses archives for comprehensive protection.

2.Custom Policy

Administrators can choose to define their own policies, perhaps for compliance or governance reasons, which take precedence over spam blocking rules delivered to the system automatically through Barracuda Energize Updates. The Barracuda Spam Firewall enables administrators to set custom content filters based on the subject, message headers, message bodies and attachment file type.

3.Intent Analysis

All spam messages have an "intent" - which is to get a user to reply to an email, visit a Web site or call a phone number. Intent analysis involves researching email addresses, Web links and phone numbers embedded in email messages to determine whether they are associated with legitimate entities. Frequently, Intent Analysis is the defense layer that catches phishing attacks.

Connection Management Techniques

The connection management techniques generally require less processing. For typical small or medium businesses, more than half of the total email volume can be blocked through connection management techniques. Very large Internet Service Providers (ISPs) or even smaller Web hosts while under attack, may observe block rates at connection management layers exceeding 99 percent of all email volume.

Two Main Concepts for Blocking Unwanted Email

  1. Connection Management techniques involve dropping incoming mail connections before actually receiving the message
  2. Mail Scanning techniques involve analysis of messages after they have been received

Barracuda Anti Spam Technology

The Barracuda Spam Firewall provides comprehensive spam-blocking for your organization. The algorithms and methods used by the Barracuda Spam Firewall are the most comprehensive and most advanced in the industry.

The Barracuda Spam Firewall even includes Bayesian analysis which has been shown to be the most effective and most accurate method of blocking spam.

Behind the industry-leading initiatives of Predictive Sender Profiling and Barracuda Real-Time Protection are 12 explicit defense layers including: Denial of Service and Security Protection, Rate Controls, IP Reputation Analysis, Sender Authentication, Recipient Verification, Virus Protection, Policy (user-specified rules), Fingerprint Analysis, Intent Analysis, Image Analysis, Bayesian Analysis, and a Spam Rules Scoring engine. The methods and techniques used by the Barracuda Spam Firewall are continuously updated via the hourly Barracuda Energize Update Service, to stay one step ahead of spammers and virus writers.

The Barracuda Spam Firewall provides a number of parameters that can be adjusted and tuned for your specific environment. Some of the algorithms employed to block spam are listed below with a short description.