BUGS in widely used networking technology expose tens of millions of personal computers, printers and storage drives to attack by hackers over the regular internet, researchers say.

The problem lies in computer routers and other networking equipment that use a commonly employed standard known as Universal Plug and Play (UPnP). UPnP makes it easy for networks to identify and communicate with equipment, reducing the amount of work it takes to set up networks.

Security-software maker Rapid7 said in a white paper released on Tuesday that it discovered between 40-million and 50-million devices vulnerable to attack due to three separate sets of problems its researchers have identified with the UPnP standard.

The long list of devices includes products from manufacturers including Belkin, D-Link, Cisco Systems’ Linksys division and Netgear.

Chris Wysopal, chief technology officer of security-software firm Veracode, said he believed that publication of Rapid7’s findings would draw widespread attention to the still emerging area of UPnP security.

"This definitely falls into the scary category," said Wysopal, who reviewed Rapid7’s findings. "There is going to be a lot more research on this, and it could be a lot scarier."

Rapid7 has privately alerted electronics makers about the problem through the CERT Co-ordination Centre, a group at the Carnegie Mellon Software Engineering Institute that helps researchers report vulnerabilities to affected companies.

"This is the most pervasive bug I’ve ever seen," HD Moore, chief technology officer for Rapid7, said. Moore, who created a widely used platform known as Metasploit that allows security experts to simulate network attacks, said he expected CERT to release a public warning about the flaw.

The flaws could allow hackers to access confidential files, steal passwords, take full control over PCs as well as remotely access devices such as webcams, printers and security systems, according to Rapid7.

Moore said there were bugs in most of the devices he tested and that device manufacturers will need to release software updates to remedy the problems. In the meantime, he advised computer users to use immediately a free tool released by Rapid7 to identify vulnerable gear, then disable the UPnP functionality in that equipment.

Moore said hackers have not widely exploited the UPnP vulnerabilities to launch attacks, but both Moore and Wysopal expected they may start after the findings are publicised. People who own devices with UPnP enabled may not be aware of it because new routers, printers, servers, webcams, storage drives and "smart" or web-connected TVs are often shipped with that functionality turned on by default.

"These devices seem to have had the same level of core security for decades. Nobody seems to really care about them," said Moore.

Veracode’s Wysopal said some hackers have likely already exploited the flaws to launch attacks. "If they are going after executives and government officials, then they will probably look for their home networks and exploit this vulnerability."

Rapid7 is advising users to disable UPnP in devices they suspect may be vulnerable to attack. The firm has released a tool to help identify those devices on its website, www.rapid7.com.