A rash of attacks on Windows 2000 servers has left Microsoft security experts baffled.
The software giant issued a security warning about the attacks, which seem to be based around Trojan horse programs, but unusually the firm has yet to suggest any protective measures.
But more recent missives on the firm's website seem to indicate that the attacks are more likely to be the work of hackers rather than passive worm attacks.
Microsoft admitted that certain files on machines running Windows 2000 seem to be compromised.
One file, 'gg.bat', attempts to connect to other computers using various administrator accounts. If successful, the file will then copy other files over to the compromised system.
Another, 'seced.bat', changes security settings on the compromised system to make it easier for a hacker to log onto the computer at a later date.
The last file, 'gates.txt', contains a list of numerical internet addresses.
A Microsoft spokesman said that, although a significant number of companies had reported these sorts of attacks, the rate is dropping.
A statement on the company's website suggested that it can't work out whether the attacks use some new flaw in its operating system, or are successful because users may not have up-to-date Windows 2000 system patches.
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