POSTINI REPORTS INCREASE IN SPAM, DECREASE IN IM ATTACKS DURING THE MONTH OF FEBRUARY

Virus Attacks Comprise 1.5 Percent of All Email; Inbound TLS Encryption Volumes Up to 7% Percent of All Legitimate Email

SAN CARLOS, CA, March 06, 2006 – Postini, the global leader in Integrated Message Management, today announced that spam volumes and encryption volumes were on the rise, viruses returned to normal levels, and IM attacks were down during the month of February. Postini processed over 22 billion emails in February and found that after blocking 14 billion emails as DHA’s (directory harvest attacks), malicious attacks and email to invalid recipients, spam totaled just over 4 billion, an increase of two percent compared to January, bringing the total amount of spam quarantined to 73 percent for the month. The company also filtered 2.2 million instant messaging (IM) conversations in February, stopping such IM worms as FakeMSN, Lamo.Worm and Loxbot. Unchecked, these IM worms can install spyware, adware, keystroke loggers, and root kits on victims’ PCs.

Spam was most prevalent on February 18, with 150 million messages quarantined, accounting for 82 percent of all messages stopped.

“The increase in spam was due to an increase in tax preparation offers and other financial service offerings that are more prevalent as we approach April 15,” said Andrew Lochart, senior director of marketing for Postini.

Postini measurements show that Inbound TLS encryption volumes grew slightly from 6.5% percent of all legitimate inbound traffic to 7.0% percent, and outbound TLS volumes grew from 1.5 percent of all messages to nearly 3 percent, indicating the continued adoption of encryption by customers.

While spam was on the rise, viruses returned to their normal level of 1.5 percent of all email in February, with Postini stopping a total of 40,185,146 viruses. Even the “mywife” virus (aka “kama sutra,” aka “nyxem”), which on February 3 threatened to delete files on infected computers, ranked only eighth on Postini’s top ten viruses for the month.

The top five viruses for February were:

Phishing volumes in February totaled 2,869,819 which was 65 percent lower than the very volatile month of January.

Postini protected its customers from more than 19 million DHAs, a 47 percent decrease compared to January’s 29 million DHAs.

Legitimate email as a percentage of total SMTP connections remained virtually unchanged from January to February. Only 15.5 percent of all messages were legitimate email.

Postini’s StatTrak™ is available to users at www.postini.com/stats and provides the most up-to-date statistics on the latest viruses, spam and DHA attacks.

About Postini
Postini is the global leader in Integrated Message Management, providing compliance, security, availability, and visibility solutions for corporate email and instant messaging. Postini offers a complete suite of services including message archiving and discovery, spam and virus blocking, and messaging continuity. The company’s powerful managed services infrastructure seamlessly integrates with customers’ infrastructure, providing uncompromising security for more companies than any other provider in the world. Postini’s services protect organizations from a wide range of threats, reduce compliance and legal risks, ensure reliable communications, and enable the intelligent management and enforcement of enterprise policies that protect companies’ intellectual property, reputations and business relationships. For more information contact Postini at 866-767-8461, or visit http://www.postini.com.