Thomas Weisel Partners was looking for a way to ensure that all of its Internet traffic would exit the network through secure servers, without bringing worms and viruses in. But like any good investment bank, Thomas Weisel bypassed the conventional choice -- and found something better.

Instead of deploying an intrusion detection systems, as most companies would do in a similar situation, Thomas Weisel is using an anomaly detection system, Arbor Networks Inc.'s PeakflowX, to solve its security problem.

The San Francisco-based banking firm -- which employs about 550 people and maintains offices in Boston, New York, Palo Alto, and Mumbai -- was looking for a tool that would maximize the resources of its small IT security staff, according to CISO Beth Cannon. Initially, when an outbreak occurred, Cannon and the IT staff would search through logs and deploy packet analyzers to determine what was happening on the network -- a process that was extremely time-intensive.

Cannon and her staff considered an IDS, but after investigating further, determined that such a system would actually add to the workload -- without providing detailed information necessary to take action against misbehaving hosts. The team then took a closer look at PeakflowX, because it "would give a view of what was happening on the internal network and by default what was going in and out of the network."

After deploying PeakFlowX, Thomas Weisel suffered two incidents in which malware was introduced to the network via laptops. The bank uses Symantec anti-virus software, but the AV product did not detect new variants on the laptops. With PeakFlowX, Cannon can issue trouble tickets asking the IT staff to investigate a misbehaving computer before the infection escalates. Cannon didn't track the productivity savings for the incidents, but in the cases where network traffic was slightly degraded during an early outbreak, she estimates that the IT group cut its time expenditure by a ratio of about forty to one.

Cannon also integrated PeakflowX into Microsoft's Active Directory so that she could tie a user to a computer. She could then correlate "what machine [and user account] tried to access a financial server that it had never accessed previously" -- a key element for Sarbanes-Oxley compliance reporting as well as for meeting Securities and Exchange Commission and NASD requirements for logging all electronic transmissions.

Cannon does have to explain to auditors why anomaly detection is as good as, or better than, having an IDS. A signature-based IDS won't detect problems it doesn't know about, but with PeakFlowX, Cannon can combine information from vendors such as Websense and Symantec, as well as controls on servers, with reports from the anomaly detection system to provide immediate, useable information about intrusions and anomalous activity. "What we find, and probably every security manager finds, is that no one system gives you everything," Cannon says. "With a few systems combined, you can get a reasonable picture of network activity."

— Mike Fratto, Editor at Large, Dark Reading

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