Former CEO of AirPrism and Enterprise Software Marketing Executive to Lead Marketing for Rapidly Growing Enterprise Security Management Company

CUPERTINO, Calif. – May 25, 2005 – ArcSight, Inc., the global leader in Enterprise Security Management (ESM), today announced the appointment of Steve Sommer as senior vice president of Marketing and Business Development.

“We’re excited to have such an exceptional and experienced executive as Steve to lead our marketing and business development efforts,” said Robert Shaw, chairman and chief executive officer of ArcSight. “In a market that is growing and evolving as rapidly as ours is, ArcSight will certainly benefit from an executive who has a strong strategy foundation and extensive experience in other fast-growing enterprise software companies.”

Prior to joining ArcSight, Mr. Sommer was president and chief executive officer of AirPrism, a VC-funded company that provided mobile and wireless device management software, and led the company through its acquisition by Wavelink Corporation in October 2004. Previously, Mr. Sommer held the position of senior vice president of Marketing and Business Development at Portal Software where he led Portal’s market expansion to become a global leader in customer management and billing software for IP and communications services.

Before joining Portal, Mr. Sommer was vice president of Worldwide Marketing at Informix Software, which was subsequently acquired by IBM. Mr. Sommer has more than 25 years of marketing and business development experience, having also held positions at Cognos, Digital Equipment Corporation, and Procter & Gamble, and served as a consultant with McKinsey & Company. Mr. Sommer received B.S. degrees in chemical engineering and management from M.I.T. and an MBA from Harvard Business School.

“The only effective way for organizations to understand and manage the risks and threats to their information assets, and to secure those assets, is with Enterprise Security Management software,” said Steve Sommer, senior vice president of Marketing & Business Development for ArcSight. “I am thrilled to join ArcSight, a company that in a relatively short time has already established itself as the market leader.”

About ArcSight

ArcSight, Inc. is the leading provider of Enterprise Security Management (ESM) solutions. Winner of CMP’s Network Computing Editor’s Choice and Network World Best of Tests awards, and numerous other awards and recognitions, ArcSight ESM 3.0 enables enterprises to centrally manage information risk. By comprehensively collecting and analyzing security data, ArcSight ESM 3.0 provides accurate, real-time internal, external threat management and compliance reporting. ArcSight customers include companies in the Fortune top 5 of financial services, banking, telecommunications, high-technology, retail, healthcare, and biotech industries -- and more than 20 of the top 30 federal agencies.

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