Why are so many Israelis arrested over illegal arms deals worldwide?

At least 7 Israeli arms dealers are currently in jail in four countries - the United States, Russia, France and Britain - on charges of illegal arms dealing. Some of them are also suspected of crimes such as forgery, bribery, money laundering and violating UN Security Council embargoes. All are men in their fifties or sixties. All are well to do (or were in the past), having made most of their money in international arms dealing or in exporting security services and equipment from Israel. They served in the Israel Defense Forces and reached mid-level ranks (from captain to lieutenant colonel), and when they were arrested, they denied the charges. All seven are familiar faces in the corridors of the defense establishment, and at one time received arms dealing permits from the Defense Ministry.