Wireless vendor Meru Networks has unveiled a new system to protect business users from eavesdroppers hoping to hack in to their wireless networks.

Meru's new RF Barrier is intended to protect users from so-called 'parking lot' attackers, who passively listen for insecure wireless traffic which they can use to obtain passwords and other critical security information.

Meru said that because RF Barrier used directional antennas and selective enforcement technology, it would not impact internal wireless traffic or that from other WLANs close by.

“Previously, both wireless security and infrastructure vendors have focused on protecting the connection and the back-end network, while the perimeter – where attacks cannot be detected – has remained undefended,” said Joe Epstein, Meru’s senior director of technology in a statement.

In 2007 hackers using a telescope wireless antenna siphoned off wireless traffic from US retailer TK Maxx, which they subsequently used to crack back office network security at the firms parent company TJX, resulting in nearly 50 million credit and debit card records being taken.

RF Barrier will be available this September and can use any Meru 802.11a/b/g access points. Pricing for a starter kit including four antennas, four APs, cabling and software is £1,800 ($3,595).