Microsoft says parts of the source code for its closely guarded Windows programs have leaked onto the Internet to possibly expose its products to hackers and illicit copying.
Microsoft said that copies of the source code from its Windows NT and Windows 2000 operating systems were being traded over the Internet, but that the copies comprised a tiny portion of the millions of lines of code used to create its products.
Source code is the intellectual property and lifeblood of any software company, since it is the basic language used to create software programs. Microsoft has only shared its source code with close partners and carefully chosen organisations, with legal agreements that threaten litigation in the event of that any of is leaked.
The code appeared to come from an unidentified software developer with access to Microsoft's code. Software companies that create programs running on Windows need access to source code to build their own products.
One main risk in having source code exposed to the public is the possibility that hackers could break into computers running Windows NT or Windows 2000 and destroy or steal data.
Although the company said that was unlikely, given the relatively small portion of code that had been circulating, a greater risk could come from others using the code as a base for developing software that competes with Windows.
Microsoft is the world's biggest software company. More than 9 out of 10 personal computers, run on its software.