Once a federal judge gives consent for the lawsuits to go forward, the company can subpoena the Internet service providers from which the phishing scams originated in an attempt to force the ISPs to reveal the identities of the account holders.

Microsoft's lawsuits were brought under the Lanham Act, a federal trademark protection law that carries a maximum of $1 million fine per violation.

Every one of the sites named in the lawsuits, which were online sometime between October 2004 and March 2005, has already been taken down, said Aaron Kornblum, Internet safety enforcement attorney at Microsoft. One of the primary goals of the legal attack is tracking down the individuals responsible for creating the fraudulent sites, he said.