Erika Butner, with her attorney Gloria Allred, told reporters in Los Angeles on Wednesday that photos of her and other victims were posted without authorization to a Facebook group and to Google Drive.
One person who commented on her photo asked others to share nudes of her, she said.
"I am disheartened and disgusted with this scandal," said Butner, who served for four years until June 2016.
Allred said she sent a letter to Gen. Robert B. Neller, commandant of the Marine Corps, requesting he meet with women who have suffered online harassment. Butner said she wants to make suggestions for change and discuss how Marines can have more respect for each other.
The posting of lewd photos without consent is a violation of the US Code of Military Justice, Allred said.
"This is a stain on their own conduct," she said. "Changes need to be made. Consequences need to be meted out."
Allred would not comment on whether she would seek criminal charges.
Marisa Woytek, who joined Allred at the news conference, released a statement but didn't speak to the media. Woytek, an active duty Marine, said photos of her posted online showed her fully dressed but still drew comments from men advocating sexual violence.
She thanked Neller for a video he posted on a military images website on Thursday.
"When I hear allegations of Marines denigrating their fellow Marines, I don't think such behavior is that of true warriors or war fighters," Neller says on the nearly four-minute video
. He calls the actions of the Marines United members "embarrassing to our Corps, our families and the nation."
He invited women to report harassment or abuse to their superiors, legal counsel or chaplains.
Neller will brief the House Armed Services Committee next week on the Marines United scandal, congressional aides said. The March 16 briefing will be closed to the press, the aides said.
A Marines spokesman said the Corps was unable to comment at this point on Allred's request.
Butner said she notified the Naval Criminal Investigative Service and Google in January about a shared drive that housed the photos of female service members and contained personal information about many of them.
Neither she nor Allred would comment on the Navy's response. Navy officials have said they cannot comment on an ongoing investigation.
So far, at least one person has been disciplined in connection with the postings, a US military official told CNN earlier this week. He was an IT subcontractor working for a firm with a support contract for the Marines.
Butner, who was told about the Marines United activities by a friend, said the behavior should not be dismissed as "boys being boys."
"As a rape survivor, I can tell you that this exact behavior leads to the normalization of sexual harassment and even sexual violence," said Butner, who didn't disclose when she was raped.