Hammarby fans invaded a closed section of a stand above away supporters during their match against GAIS on September 19 and began throwing objects at rival fans below.
The game was delayed for almost an hour before restarting. Hammarby went on to win 3-1.
"The attack was well-planned and posed a significant risk to the lives and health of others," the disciplinary committee of the Swedish FA said in a statement.
"This was caused by non-functioning security, and this is something the committee takes a very serious view of," the statement added.
The committee rejected an appeal from GAIS that the game should not have restarted and that they should be awarded a 3-0 victory.