MANILA, Philippines -- Philippine websites remain at risk of being redirected even if their Internet service providers (ISPs) have patched their DNS servers.

Jun Valdez, vice president for network engineering and operations at Prime Communications (formerly Pacific Internet), stressed that the recent flaw detected in the Internet's domain name system or DNS is a global problem.

This recent vulnerability was detected more than a month ago and concerns the DNS system, which translates Web addresses into numerical IP addresses.

Experts fear that the flaw can be exploited in such a way that a user who enters a legitimate address may be directed to a different site or worse, a bogus mirror site that's actually designed to gather sensitive information such as passwords and credit card numbers.

Valdez said local companies, however, remain at risk even if they are using secure DNS servers run by their ISPs simply because their customers or end-users are connected through another ISP.

"A local bank who is our customer, for example, is assured since we have patched our DNS servers already. But a customer from Hong Kong, for example, who is transacting with our customer, can still be redirected to another site if his of her ISP is using unsecured DNS servers," Valdez said.

Security researcher Dan Kaminsky first detected the flaw early July and discussed it at length in Black Hat security conference Defcon a month later, although was thought to have been already exploited by hackers as the vulnerability was supposedly leaked to the public.

In a phone interview with INQUIRER.net, Valdez admitted he and his team found it tedious to install recommend patches after this latest vulnerability was announced.

"We were literally scratching our heads this time. Normally, enterprise users are given time to update their servers so as not to disrupt production," he said. "We have informed our corporate customers about the updates and advised them to check if their DNS servers are secure, if they are not using ours."

INQUIRER.net has received feedback from readers calling attention to local Web addresses that have been redirected instead to different sites.

Mailing lists have also discussed DNS problems especially those using PLDT myDSL and Smart Bro. But officials have yet to responds to queries sent by INQUIRER.net.

As of this writing, other ISPs and service providers have yet to respond to questions sent out by INQUIRER.net.

End-users can check upon their service providers if they are using secure DNS servers by redirecting browsers to the following servers from OpenDNS: DNS1: 208.67.222.222 and DNS2: 208.67.220.220.