Mossad would be much more cool and sick (like skateboarders) if they tracked down these guys' names and then made Advice Dog memes out of them and got frontpaged on Reddit, talk about cutting edge information warfare
e: apostrophe goes after the plural S
e2: Israel is actually under sustained cyber attack from all over, though particularly from the obvious antagonists in the West Bank and Gaza. They also have some really beastly cyberware capabilities (the US worked with them on Stuxnet), which I think are part of military intelligence rather than Mossad. Given that they have constant and much more important cyberattacks to deal with I suspect this is fairly low on their list of priorities compared to the hostile state and non-state actors right on their doorstep.