Well it turned out to be not that easy as simply adding few lines. Im not sure if it even works since game rewrites preferences.prop each time you start Spore, sorry folks.
For those who want to try another solution and not scared of editing core game files you might try this:
download
Link full 5mb version
Go to your game directory and locate file called spore_game.pakage inside data folder and make a copy of it somewhere. Then go to your user directory, locate spore folder and inside it folder called "Games" make a copy of it aswell.
Open Splview that you previously downloaded, select tools, select "unpack DBPF" and find your spore_game.pakage, wait till it unpacks it, then you'll see a folder inside spore Data directory called Spore_Game, inside it you'll see thousands of files, one you need should be called SP-_CHT-024A0E52-00000000-658B0AB2.txt it should be around 276kb.
Open that file and locate
property universeSimulatorPirateRaidFrequency 0x031e7620 float 600
property universeSimulatorPirateRaidMinTime 0x031e761f float 300
property universeSimulatorPirateRaidDefendedRatio 0x031e7621 int 500
property universeSimulatorPirateRaidAllyFrequency 0x039620a6 float 600
property universeSimulatorPirateRaidAllyMinTime 0x039620ae float 300
property universeSimulatorPirateRaidPlunderFrequency 0x0397a072 float 600
property universeSimulatorPirateRaidPlunderMinTime 0x0397a073 float 300
property universeSimulatorWarAttackMinTime 0x031e94b7 float 100
property universeSimulatorWarAttackFrequency 0x031e94b8 float 300
property universeSimulatorHappinessDisasterMinTime 0x04f3b63e float 100
property universeSimulatorHappinessDisasterFrequency 0x04f3b63f float 300
property universeSimulatorGrobTeaseAttackFrequency 0x031e94b9 float 100
property universeSimulatorGrobTeaseAttackMinTime 0x031e94c0 float 300
property universeSimulatorGrobWarAttackFreqExtremelyAware 0x031e94c1 float 40
property universeSimulatorGrobWarAttackFreqVeryAware 0x031e94c2 float 80
property universeSimulatorGrobWarAttackFreqAware 0x031e94c3 float 160
property universeSimulatorGrobWarAttackMinTime 0x031e94c4 float 60
property universeSimulatorBiosphereCollapseTime 0x04488192 float 600
property universeSimulatorBiosphereCollapseFrequency 0x044881a3 float 300
replace all values with higher values to lower the frequencies of attacks (yes it seems that the higher the value is the lower actual attacks/disasters are)
Now save it, go back to splview and select Pack DBPF from tools menu, then pick any file inside Game_Pakage directory in first menu and type spore_game in the save file name in second menu. Wait till it finishes packing. Now just replace spore_game.pakage inside data directory with one you just created. Be sure that you have actually done a copy of it before replacing file.
Proly youll have to delete your save games and start completely new game. Anyway im not responsible to whatever damage you can do to your game and you might not be able to use sporopedia if you modify any of your game files.
For those who wondering there are other different options, including spaceship travel radius, tools, ai behavior and others.