The Army Times initially reported on the posting of the list. Its parent company employs Sterner.

In a letter to Secretary of the Army John McHugh on Wednesday, Congressman Duncan Hunter (R-California) - a veteran of both the wars in Iraq and Afghanistan and a member of the House Armed Services Committee - voiced his concern and demanded a review.

"It is the obligation of the Army to maintain an awards process that is devoid of lapses in communication, transparency and most importantly, ensuring America's military heroes are honored with the combat decorations they deserve," Hunter said.

"I'm also concerned that this issue could be representative of a larger problem and I would encourage the Army to undertake a review of its awards process," Hunter said.

Army officials said an investigation of how the publication of the Social Security numbers online occurred has begun.

"We take this matter very seriously," according to Army spokesman Col. Jonathan Withington, who said the service took "immediate corrective action" once the soldiers' information was discovered on the Web. "The contractor was notified immediately and removed the unofficial file."

Withington said the Army was notifying "affected persons to make them aware of the circumstances" in accordance with military policy.

It is unclear how long the database was online.

The Army contractor at the center of the controversy, Brightline Interactive of Alexandria, Virginia, did not respond to questions from CNN.