https://netzpolitik.org/2013/angriffe-auf-informationssystem...

(Also the links there.)

Or a more "official" statement (as the German Wikipedia is mostly in the hands of state authorities), with some groundless relativization:

https://de.wikipedia.org/wiki/Vorbereiten_des_Aussp%C3%A4hen...

All "dual use" tools (like a simple port scanner!) can bring you into jail. That's a fact. The law doesn't have any exceptions for "friendly use"… (No matter what some "experts" cited on Wikipedia may say. That's just the usual German Wikipedia blow smoke…)