Microsoft last Friday said it was looking into a long-known vulnerability in Internet Explorer (IE) that could be used to access users' data and Web-based accounts.
The bug can allow hackers to hijack Web mail accounts, steal data and send illicit tweets, said Google security engineer Chris Evans in a message posted on the Full Disclosure mailing list.
Evans also published a demonstration that showed how the flaw in IE8 could be used to commandeer a user's Twitter account and send unauthorized tweets.
The vulnerability, known as a "CSS cross-origin theft" bug, has a long history. Researchers at Carnegie Mellon University, who recently published a paper (download PDF) on the subject, have traced it back as far as 2002. Those researchers will present their paper at the Conference on Computer and Communications Security next month.
Even so, the flaw received little attention until Evans blogged about it in December 2009. He had submitted a bug report for Chrome eight months earlier.
Although Microsoft has not patched the vulnerability in IE8, other browsers, including Firefox, Chrome, Safari and Opera, have fixed the flaw. Google patched the bug in Chrome last January, while Mozilla did the same in July with Firefox 3.6.7 and Firefox 3.5.11.