The hackers responsible claimed that they targeted Connectusers.com to highlight how slowly the software company is at fixing security issues, reports The Hacker News.
Connectusers.com provides users with a platform to share opinions on Adobe's conferencing service Connect.
The firm closed the forum when a file dump containing user details appeared on Pastebin, a site commonly used by hackers to boast about their successes.
More than 150,000 e-mail addresses and passwords believed to belong to Adobe employees, military personnel and NASA employees were leaked during the breach.
Adobe has apologised over the breach and insisted that it is "working diligently to restore forum services as soon as possible."
A hacker under the alias of ViruS_HimA has claimed responsibility for the attack, and vowed to strike at Yahoo next.