Frustrated with what he calls a lack of response from Microsoft and Amazon.com, a security researcher has gone public with details of flaws on the two companies\u2019 websites.The flaws could be used by attackers to steal "cookie" data files that would allow them to access Amazon.com and MSN accounts, or to display a fake log-in page that could be used in phishing attacks, according to Yash Kadakia, the independent security researcher who discovered the flaws.Although the cross-site scripting flaws he discovered are generally considered to be low-risk problems, Kadakia\u2019s attack involves a technique called carriage return line feed injection, which can be used in a more serious and widespread attack, he said.Kadakia said he first notified Microsoft of the problem about a year ago. But he said he was not taken seriously until late last week, when he posted screen shots of the flaw being exploited on his website.The Amazon.com flaw was discovered in December, but after some initial discussions with the Web retailer, the vulnerability remained unpatched, Kadakia said. "The conversations got dropped off somewhere," he said.A spokesman for Microsoft\u2019s public relations agency said the flaws are now being investigated. Amazon.com executives were unable to comment for this story.Though Microsoft has made much of its focus on security, the company appears to be slower at dealing with security issues relating to its Web properties than with its software products, said Stefano Zanero, the cofounder and chief technology officer at security consultancy Secure Network SRL.Web flaws such as the type discovered by Kadakia have been around for a long time, but hackers have tended to focus their efforts on operating systems. However, with operating system flaws now becoming harder to find, the bug hunters are looking for new areas, including Web applications.According to Zanero, there are a lot more Web vulnerabilities to be discovered. "We do Web application penetration testing as one of our core business services, and we\u2019ve found huge holes in every single Web application we\u2019ve tested to date," he said. "This thing is just waiting to explode."Earlier this month, a worm began making the rounds at Yahoo\u2019s Web-based e-mail server. Called JS.Yamanner@m, the worm did not cause widespread damage, but it drew attention to the vulnerability of some Web applications.The slow response by Microsoft and Amazon.com shows that Web-based vulnerabilities are not a top concern to many websites, Zanero said. "It\u2019s the sluggish handling of these things that\u2019s surprising," he said. "These vulnerabilities were on two of the world\u2019s best-developed websites, somebody found them out, and nobody cared for a year or so."Meanwhile, Amazon.com and Microsoft are now trying to fix the bugs, Kadakia said.Not all security experts agreed that the bugs Kadakia has discovered are critical. "These are actually fairly common types of exploits," a Symantec spokesman said in an e-mail note. "Nothing really to write home about."Nevertheless, Symantec appears to be taking the problem more seriously than\u00a0is Microsoft, Kadakia said. The security researcher recently notified Symantec about a similar flaw on its own website. "They fixed it in a week," he said.-Robert McMillan, IDG News Service (San Francisco Bureau)Check out our CIO News Alerts and Tech Informer pages for more updated news coverage.