"Vigilance and force protection considerations remain a priority for commanders and their personnel," US Marine Corps Lieutenant Colonel John Caldwell said in a statement.
"It is recommended Marines and family members check their online/social footprint, ensuring privacy settings are adjusted to limit the amount of available personal information."
The warning came after a group calling itself the Islamic State Hacking Division put the allegedly hacked information about members of the air force, army and navy, included photos and ranks, on the Internet, according to monitoring group SITE Intelligence.
A defense source, however, told The New York Times most of the information was in fact available in public records and did not appear to have been hacked from government servers.
"With the huge amount of data we have from various different servers and databases, we have decided to leak 100 addresses so that our brothers residing in America can deal with you," the group wrote.
"Now we have made it easy for you by giving you addresses, all you need to do is take the final step, so what are you waiting for?"
A Defense Department official told AFP they were looking into the posting.
"I can't confirm the validity of the information, but we are looking into it," the official said.
The United States is leading an international coalition targeting the Islamic State group in Iraq and Syria, where the Islamist militants have taken over swaths of territory.
IS has claimed responsibility for hacking attacks in the United States in the past, including against Central Command, which oversees the air war against the IS group.
The words "CyberCaliphate" and "I love you ISIS" replaced Central Command's usual logo on Twitter and YouTube before the pages were suspended.
This month, the FBI said it was investigating a string of hacks that defaced US websites with imagery from the Islamic State jihadist group.
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