HP has agreed to buy security event management firm ArcSight for $1.5bn.

The deal, rumoured over the weekend and announced on Monday, is the IT giant's second significant acquisition in two weeks, following the purchase of storage outfit 3PAR. It also follows last month's deal to buy application security tools firm Fortify Software.

ArcSight, which received funding form the CIA's venture capital arm in the early days of the firm, markets technology that helps corporates to make sense of logs from firewall and intrusion prevention appliances. Its security information and event management (SIEM) products also help companies to meet corporate compliance regulations.

HP said the acquisition of ArcSight "will provide customers the ability to proactively monitor real-time events, assess risks and respond quickly to threats".

ArcSight, which was founded in 2000 and floated two years ago, made $3m on revenue of $48.1m for the quarter ending 31 July. HP is offering $43.50 per share for ArcSight's stock, a premium of 25 per cent on its closing price on Friday.

The HP/Arcsight tie-up follows less than a month after Intel's $7.7bn much puzzled over acquisition of McAfee, Symantec’s recent acquisition of PGP, and IBM’s purchase of BigFix. IT giants are buying security firms like money was going out of fashion in one of the most intense periods of consolidation in the sector to date. ®