Khalid Shaikh, former CEO of YouSendIt, has been indicted by a grand jury on four counts of mail fraud after allegedly launching four denial-of-service (DOS) attacks against the company's servers, the U.S. Department of Justice said.

Shaikh allegedly used the ApacheBench software program to launch the DOS attacks against YouSendIt's servers between December 2008 and June, the DOJ said in a press release.

Shaikh co-founded YouSendIt in January 2004 and served there as CEO and later CTO until November 2006. YouSendIt provides a service for sending and receiving large files over the Web.

Each of the DOS attacks temporarily stopped the servers from handling legitimate network traffic and stopped YouSendIt's customers from using the company's services, the DOJ said.

The maximum penalty for each count of mail fraud is five years in prison, three years of probation and a fine of US$250,000, plus restitution if appropriate.

However, any sentence following conviction would be imposed by the court after consideration of the U.S. Sentencing Guidelines and the federal statute governing the imposition of a sentence, 18 U.S.C. § 3553.

Shaikh was indicted Wednesday in U.S. District Court for the Northern District of California.

YouSendIt's servers are based in San Jose, California, and the company's headquarters are nearby in Campbell, California.