UPDATE: Apparently the DDoS attack is being caused by a trojan some 4chan users have downloaded. If you've downloaded ANY FILES linked on 4chan, please immediately go to this link and download the removal tool: VundoFix by Atribune.
Otherwise, all users are encouraged to run a full system scan to ensure
their system is clean. The sooner people do this, the sooner /b/ &
/r9k/ will return.
EDIT: Trojan remover updated. Apparently VundoFix is better than Symantec.