Donald Randolph, Mitnick's attorney, confirmed his client had struck a plea deal with the U.S. attorney's office but declined to give details, according to the Associated Press.
"We don't want to say anything that would influence the court's decision," he told the AP. "We are cautiously optimistic that the court will accept this agreement."
Chris Painter, one of the attorneys prosecuting Mitnick, confirmed that a court brief in the case was filed under seal on Tuesday but declined to comment further. The story was first reported by Ziff Davis Network News and the Los Angeles Times.
The deal comes a month before Mitnick, 35, was scheduled to go on trial on charges of computer and wire fraud.
If the plea agreement is approved by U.S. District Judge Mariana Pfaelzer, Mitnick would likely receive five years in prison. Mitnick will likely receive credit for the 49 months he has already spent in jail since the FBI raided his apartment in Raleigh, North Carolina, meaning he could be released within the next year.
Mitnick would be required to stay away from computers for at least three years, an anonymous source told the AP.
Mitnick is accused of breaking in to numerous computer networks, accessing thousands of credit card numbers, and stealing software over a three-year period.
His capture by the FBI was the subject of the book Takedown. Since his arrest in February 1995, he has been supported by hackers across the world who claim the government has exaggerated the harm Mitnick's exploits caused.
Hackers have taken over several Web sites, including The New York Times and one devoted to former White House intern Monica Lewinsky, and have left messages in support of Mitnick.