Their military is very good at cyber-warfare. The gap has narrowed in the last decade, but before that there wasn't even a distant second, maybe Russia. People serve in those units, acquire very useful and specific skills, then start companies that offer commercial variants of cyber-warfare, or become subcontractors for other governments.
Mandatory military service, too. You have to imagine that the US would have a similarly disproportionately-scaled cyber-warfare industry if it also had mandatory military service and good sorting of capable people into those units.
They're even better at sextortion. Jeffrey Epstein is the posterchild for their efforts, along with his Mossad agent father-in-law Robert Maxwell, and handler Ehud Barak. It's likely that many of Israel's "triumphs" over the last few decades were less a result of hacking and more a result of blackmail, similar to the FSB/KGB.