If approved by U.S. District Judge Marianna Pfaelzer, the deal reached this week could close the government's long case against Mitnick.
ZDTV's CyberCrime first broke news of the Mitnick deal Wednesday night. On Thursday, Donald Randolph, Mitnick's court-appointed attorney, confirmed that a deal had been struck, but would not discuss details of the agreement, which has been filed under seal for review by Pfaelzer.
"We don't want to say anything that would influence the court's decision," Randolph said. "We are cautiously optimistic that the court will accept the agreement."
Thom Mrozek, a spokesman for the U.S. Attorney, declined to comment.
Mitnick, 35, was scheduled to go on trial in federal court April 20 on charges of computer and wire fraud.
The agreement would require Mitnick to serve another year behind bars and stay away from computers for at least three years after his release, according to a source familiar with the case.
Mitnick's formal sentence would be about five-years imprisonment, but he would be credited with time already served.
He has been accused of damaging computers, stealing millions of dollars in software from high-tech companies and using stolen computer passwords.
At the time of his arrest in 1995 in North Carolina, Mitnick was the only hacker to make the FBI's most-wanted list.
Mitnick's exploits made him a legend among many other hackers. A Web site dedicated to freeing Mitnick counts -- to the second -- the time he has spent in jail.
Last year, Mitnick supporters hacked into a New York Times Web page to post pro-Mitnick statements and criticize Times reporter John Markoff, who chronicled Mitnick's arrest in the book "TakeDown." Miramax has turned "Takedown" into a movie starring Skeet Ulrich, which is due for release this year.