Greenspan prepared a six-page white paper detailing his findings.

"When it is my documents that are up there, and they're giving other people potential access to them, that's not OK," Greenspan said. "I'm glad they shut down the site. That means they're taking it seriously."

He was, however, not happy that it took the agency more than 20 days to investigate his claims before shutting down the Web site. "I hope they put a bit more thought into it this time."

The eOffer/eMod Web site uses digital authentication technology to ensure the integrity of data and to electronically sign the vendor's proposal or modification request, according to the site. Digital certificates are required to use the Web site.

"GSA took immediate action to repair a glitch that compromises the integrity of a Web tool the agency provides to make it easy for customers to prepare and submit their electronic GSA Schedule offers and Schedule contract modifications," Millikin said in an e-mail statement Friday. "Once informed, GSA immediately shut down the site and began taking corrective action. The agency also launched an intensive search to identify possible irregularities within the other electronic tools GSA provides to its customers."