Wednesday’s terror attack in Burgas, much like the one in India earlier this year, was relatively simple to carry out. And therein lies the problem for Israeli security: Unskilled operatives, with the patience to carry out surveillance and the discipline to stay off the phone and away from telltale sites on the internet, can claim Israeli lives with unsettling ease.

Prime Minister Benjamin Netanyahu released a statement some two hours after the attack, saying that “all signs point to Iran.”

If that is the case, the modus operandi is clear. Explosives and other arms can be sent in diplomatic pouches. Experts from the Quds Force or from Hezbollah’s overseas wing can be brought in as embassy staff. And Shiite volunteers can be spotted from among the immigrant faithful.

MK Yisrael Hasson (Kadima), a former deputy head of the Shin Bet, told the Israel Broadcasting Authority that there is a sizable Shiite community in the Bulgarian capital Sofia, and that collecting intelligence on Israeli groups, arriving on a charter flight from Tel Aviv, and traveling on buses to hotels, “is no problem.”

Referring to Israel’s ability to thwart terror attacks worldwide, he said there was no such thing “as a hermetic seal.”

Israel has faced a spate of terror attacks and plots during the past year. In Istanbul, in May 2011, three alleged Hezbollah operatives attempted to kill Israeli consul David Kimchi. In January, a Hezbollah man by the name of Hussein Atris was arrested in Bangkok; the investigation led the Thai police to an apartment filled with chemicals that can be used to make bombs. One month later, on February 14, a bomb went off in a Bangkok apartment located near the Israeli embassy. Police caught part of the four-person cell, and discovered eight pounds of plastic explosives in the apartment. In Azerbaijan, in January, a plot was foiled to kill the Israeli ambassador and attack a Chabad rabbi. In Georgia, in February, four years and a day to the assassination of Hezbollah military leader Imad Mughniyeh, a bomb was found on an embassy car and, later that day, an Israeli woman was injured by an explosive device placed on her car in New Delhi.

Some of the plots, like the arrest of two Iranian agents in Nairobi in late June, have been foiled by diligent intelligence work; others, by luck and the terrorists’ ineptitude. And still others have been tragically successful.

Brig. Gen. (res.) Nitzan Nuriel, up until recently the head of the National Security Council’s Counter-Terrorism Bureau, which issues travel warnings to Israelis among other things, acknowledged Wednesday on Channel 2 News that while there are certain hot spots that must be more carefully monitored – the Mediterranean basin, southeast Asia and parts of South America – “the statistics are not in our favor.”