Writers of a password-stealing Trojan horse program have managed to infect hundreds of thousands of computers - including more than 14,000 within one unnamed global hotel chain - by waiting for system administrators to log onto infected PCs and then using a Microsoft administration tool to spread their malicious software throughout the network.

...the Coreflood hackers have been successful, thanks in part to a Microsoft program called PsExec, which was written to help system administrators run legitimate software on computers across their networks...the malicious software tries to run PsExec and install malware on all other systems on the network...