Press Release

POSTINI REPORTS THAT PHISHING REMAINS MAJOR THREAT DESPITE 45 PERCENT DECREASE IN APRIL PHISHING ATTEMPTS

Number of Virus-Infected Messages Also Sharply Declined While Directory Harvest Attacks Remained Steady

REDWOOD CITY, CA, May 2, 2005 — Postini, the industry's leading provider of email security and management, today announced that phishing remains one of the major e-mail threats continuing to plague enterprise networks, despite a 45 percent month-to-month decrease in April phishing attempts. Postini protected its customers from over 9 million phishing messages in April.

Phishing is a scam in which the perpetrator sends out legitimate-looking emails appearing to come from legitimate e-commerce sites in an effort to obtain personal and financial information from the recipient. With consumers' personal information, tech-criminals then commit credit-card fraud, identity theft and even perform unauthorized bank account transfers.

Postini also reports that the number of directory harvest attacks (DHAs) by spammers against corporate email remained steady during the month of April, while the number of virus-infected messages decreased by 30 percent. Postini processed 14.9 billon messages this month and 87 percent of them were spam, including phishing, viruses, directory harvest attacks (DHAs) and other email threats. Only 13 percent of all messages were legitimate email.

"The good news is that phishing attempts and email viruses declined in April. The bad news is that despite the decrease, these email threats remain a major concern for corporations, costing valuable time, money and resources," said Andrew Lochart, senior director of marketing for Postini. "Due to the unpredictability of spammers, the increase and decrease of email threats from month to month is normal. Spammers constantly shift techniques, leading to, not only changes in the frequency, but in the composition of junk messages as well."

The top ten viruses for April were:

Virus Name Quantity Detected

1. netsky 12,247,654

2. mytob 6,803,913

3. mime 6,151,535

4. bagle 2,441,596

5. bankfraud 2,421,889

6. zafi 2,004,601

7. mydoom 1,453,998

8. lovgate 1,147,852

9. new malware-e 459,370

10. bagz 316,716

Postini's Email Stat Track 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, the global leader in secure email boundary services, stops spam and viruses, enforces policy compliance and improves email manageability. Postini's managed service model stops threats before they reach your network. For more information contact Postini at 866-767-8461, or visit http://www.postini.com.

Marty Tacktill
Senior Director, Worldwide Public Relations
650.482.3197
650.482.3109 FAX
marty@postini.com

Kimberly Canedo
Neale-May & Partners
650.328.5555 ext. 278
kcanedo@nealemay.com