ArcSight Positioned in the Leaders Quadrant of Security Information and Event Management (SIEM) Magi

ArcSight Positioned in the Leaders Quadrant of Security Information and Event Management (SIEM) Magic Quadrant

Cupertino, Calif. – June 3, 2009 – ArcSight, Inc. (NASDAQ: ARST), a leading global provider of compliance and security management solutions that protect enterprises and government agencies, today announced that Gartner, Inc. has positioned it in the leaders quadrant of the Magic Quadrant for Security Information and Event Management1 (SIEM). The report by Mark Nicolett and Kelly Kavanagh was published on May 29, 2009.

Gartner positions companies in the Magic Quadrant based on Completeness of Vision and Ability to Execute. According to the Magic Quadrant report, “The SIEM Leaders quadrant is comprised of vendors that have been the most successful in building an installed base and revenue stream within the SIEM market, have a relatively high viability rating (due to SIEM revenue or SIEM revenue in combination with revenue from other sources), and provide products that are a good functional match to general market requirements.”

“We feel our position in the leaders quadrant of the Magic Quadrant recognizes ArcSight’s dedication to arm our customers with the defensive awareness they need to protect their business,” said Tom Reilly, chief executive officer of ArcSight. “Our customers tell us that attacks, threats and compliance requirements are increasing. They need real-time awareness of all cyber threats and risks occurring throughout the organization. We believe the opportunity for SIEM and solutions like ours will only continue to grow. ”

The ArcSight SIEM Platform is an integrated set of products for collecting, analyzing and managing enterprise event information. These products, that can be purchased and deployed separately or together, depending on organization size and needs, include software and appliances for Event Collection, Log Management, Event Management, Compliance Automation and Identity Monitoring. The ArcSight SIEM Platform includes ArcSight Logger, ArcSight ESM, ArcSight Connectors, ArcSight Threat Response Manager (TRM), ArcSight Compliance Insight Packages, and ArcSight IdentityView.

To view the entire Gartner Magic Quadrant report, compliments of ArcSight, please visit
http://www.arcsight.com/library/download/GartnerMQ/

About the Magic Quadrant
The Magic Quadrant is copyrighted May 2009 by Gartner, Inc. and is reused with permission. The Magic Quadrant is a graphical representation of a marketplace at and for a specific time period. It depicts Gartner's analysis of how certain vendors measure against criteria for that marketplace, as defined by Gartner. Gartner does not endorse any vendor, product or service depicted in the Magic Quadrant, and does not advise technology users to select only those vendors placed in the "Leaders" quadrant. The Magic Quadrant is intended solely as a research tool, and is not meant to be a specific guide to action. Gartner disclaims all warranties, express or implied, with respect to this research, including any warranties of merchantability or fitness for a particular purpose.

About ArcSight
ArcSight (NASDAQ: ARST) is a leading global provider of compliance and security management solutions that protect enterprises and government agencies. ArcSight helps customers comply with corporate and regulatory policy, safeguard their assets and processes, and control risk. The ArcSight platform collects and correlates user activity and event data across the enterprise so that businesses can rapidly identify, prioritize, and respond to compliance violations, policy breaches, cybersecurity attacks, and insider threats. For more information, visit www.arcsight.com. (ARST-IR)

Forward Looking Statements
This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, including statements relating to ArcSight’s belief that the opportunity for SIEM and solutions like ArcSight’s will only continue to grow. These forward-looking statements involve risks and uncertainties, as well as assumptions that, if they do not fully materialize or prove incorrect, could cause our results to differ materially from those expressed or implied by such forward-looking statements. The risks and uncertainties that could cause our results to differ materially from those expressed or implied by such forward-looking statements include the risk that the opportunity for SIEM and similar solutions may decline or may not grow (or may not grow at levels anticipated by ArcSight), and other risks and uncertainties described more fully in our documents filed with or furnished to the Securities and Exchange Commission. More information about these and other risks that may impact the business of ArcSight are set forth in the "Risk Factors" section of the Form 10-Q for the fiscal quarter ended January 31, 2009 filed with the Securities and Exchange Commission on March 12, 2009. All forward-looking statements in this press release are based on information available to us as of the date hereof, and we assume no obligation to update these forward-looking statements.
1. “Magic Quadrant for Security Information and Event Management” by Mark Nicolett and Kelly Kavanagh, May 2009.