According to a Thursday statement by Microsoft, an unidentified flaw in the Internet Explorer (IE) was one of the holes that the attackers used for launching the reported Chinese cyber-attacks on Google and several other US companies.

As per sources, the attacker stole the source code from some of the over 30 Silicon Valley companies that were targeted - including Adobe, Symantec, Juniper Networks, Yahoo, Dow Chemical, and Northrop Grumman.

The attacks, which led Google to threaten the shuttering of its Chinese operations, were earlier speculated to have resulted from the zero-day exploit of the Abobe Reader. However, Microsoft's recent statement about the IE hole has apparently brought about the sharing of the blame for the attacks, even though it may not let Abode off completely.

Mentioning the IE flaw, Mike Reavey, director of the Microsoft Security Response Center, said in an e-mail: "Microsoft has issued Security Advisory 979352 to help customers mitigate a Remote Code Execution vulnerability in Internet Explorer. The company has determined that Internet Explorer was one of the vectors used in targeted and sophisticated attacks targeted against Google and other corporate networks."

In its advisory issued on Thursday, Microsoft elaborated that the vulnerability affects Internet Explorer 6, IE 7, and IE 8 on Windows 7, Vista, Windows XP, Server 2003, Server 2008 R2, and also IE 6 Service Pack 1 on Windows 2000 Service Pack 4.