According to a post by Riot producer Bellissimoh on the League of Legends forums, Riot has been experiencing issues with a select group of players using Distributed Denial of Service attacks to shut down games in-progress.
According to the post, the team is also doing everything they can to identify the attacking players and remove them from League of Legends. It appears they may also be considering legal action against the attackers.
If you play LoL regularly, let us know if you’ve experienced problems due to the attacks. Have they improved since the hotfix?