Researchers with Boston-based Core Security Technologies described to The Associated Press a software security hole that could allow attackers to take control of water plants, utilities and other critical infrastructure.

According to the story in The Washington Post, there's no evidence anyone else found or exploited the flaw. The company reported the hole five months ago to Citect Pty. Ltd., which makes the program CitectSCADA. The company patched it last week, though it's not clear whether all the company's clients have installed the patch.

And, the story says, the vulnerability might be found in other supervisory control and data acquisition, or SCADA, systems. The Post has reported previously that members of al Qaeda have explored vulnerabilities in SCADA systems.

SCADA systems allow remote management of computers running vital systems and are used worldwide.