You cannot attack your own faction in safe (peace) zones, but you can in PVP zones (conflict & war). PVP zones go through a cycle of Conflict, War, Peace, repeat. You lose/gain honor during war time for open world PVP.
PVP zones start at conflict and gain levels based on PVP activity. The zone then goes into war for a certain period of time once enough players have died. After the war ends, the zone goes into peace for a certain time where no players can hurt each other. After peace ends, it goes to conflict and the cycle repeats.
Some zones, like Karkasse, oceans, Mistmerrow, etc. have special conflict/war/peace timers, and some zones (like oceans) never go into peace. Special events will trigger in war time in some zones (Mistmerrow, Aegis Island, Whalesong Harbor, etc.).