Israel has a cutting-edge security technology industry and was (and still should be) considered to be the leading nation for national security.

The controversial electronic intelligence platform Pegasus was developed in Israel, and the border between Israel and Gaza was considered – before the October 7 attack – to be a leading example of using sensors and machine learning to reduce the need for human guards while not reducing the strength of the security.

But when Hamas fighters descended on the Supernova music festival on October 7, they had used drones to disable Israeli communication towers and remote-controlled machine guns. They also used unexpected tactics to breach the border. These included flooding the Iron Dome air defences with rockets, arriving on hang-gliders and demolishing the border with bulldozers (a likely echo of Israel’s use of bulldozers in occupied territories).

Despite the sophistication of Israel’s border control technology, it remains vulnerable to an enemy who understands how it works and how to compromise it. The lesson for all security agencies after the Hamas attack is to assess what secondary protection there is in their security systems and processes.

The Israelis also seem to have committed a fundamental intelligence error, which is to view the enemy through a set perspective. In assuming that Hamas was incapable and disinterested in attacking using targeted and coordinated force from the land, sea and sky (via missiles and hang-glider fighters) they discounted these tactics.

Misunderstanding Hamas’s capabilities

In the months before the attack, the Israelis had begun to view Hamas as not actively hostile, and more focused on the economy.

Hamas’s intelligence and security capability has been dangerously underestimated.

It is now clear that Hamas had intelligence about the Iron Dome air defence system, the technology on the border, and how it would alert the Israel Defense Forces if it was attacked. This unknown intelligence advantage allowed Hamas to attack over the Israeli border virtually unopposed on October 7, killing more than 1,000 Israelis, including soldiers, and abducting 199 people.

This misunderstanding of Hamas’s capabilities is probably the product of a mix of poor raw intelligence (basic intercepts that have not been verified, for instance), sophisticated misdirection and overconfidence in prior assessments of Hamas that were not shown to be wrong. Which of these reasons is accurate will only become clear in the official inquiries that will follow the conflict.

Israel is also expert in human intelligence (known as Humint). Humint is convincing someone on the other side to betray their country or their cause. People who do this are often seeking money, sex, prestige, revenge or are motivated by disaffection: they are disappointed by how their side has behaved.

Human intelligence also includes “walk-ins”. These are people from the other side offering their information. Reports from Gaza suggest that Palestinian locals would be at extreme risk if caught providing information to Israeli intelligence officers.

The loss of human intelligence – over time – seems to have degraded Israel’s understanding of the amount of weaponry entering Gaza, what the capabilities of Hamas had become and – most importantly – what Hamas’s intentions were. The enduring lesson for all governments is that to defeat an enemy, you have to separate them from the society they sit in. Effective campaigns are often founded on having secured the hearts and minds of a population.

An important lesson in all intelligence is to be prepared to think in opposites. Rather than assuming that Hamas would avoid attacking Israel in this way because of the strength of the Israeli response it should have also thought that Hamas might attack precisely to secure a strong response.

In securing that response, Hamas could reasonably predict that Israel’s negotiations with Saudi Arabia would end, and that second and third fronts would open via Syria and Lebanon placing Israel under significant pressure.

Historical parallels

A major intelligence failure in the run-up to 9/11 was in not stitching the intelligence together. But it was also in not seeing that individuals taking flying lessons that did not include a takeoff or landing might suggest a suicide attack: it was beyond the imagination of analysts.

This has its analogy in Hamas’s attack on Israel, where components of the attack like hang-glider mounted attacks, and bulldozers being used to destroy the border fence and guard posts, were not fully contemplated by Israeli officials.

Similarly, the intelligence failure in the 2005 attacks on London was an over-reliance on a thought that became accepted as fact within British intelligence, that Islamist terrorists were only interested in attacking targets abroad. Consequently, the perpetrators of 7/7 were not disrupted in time.

The lesson for all intelligence agencies is to keep challenging their assumptions and to assess what the multiple and plausible alternatives are.

Intelligence failures like those of 9/11 and the July 2005 attacks in London are often because of new terrorist tactics that analysts have failed to imagine could be possible.

Ultimately, intelligence is about avoiding surprises. But it is also about humans. And humans are unpredictable. There will never be perfect intelligence, only “best truths”.

All any intelligence agency can do is try to eliminate glaring errors. Only time will tell if the Israeli agencies had looked the wrong way, were distracted, or were simply outmatched by an enemy that was helped by a capable outsider and had chosen an unfortunately opportune moment to strike.

But the lessons for national security advisers everywhere are to maintain a system where all assessments are challenged, where opposites are explored and to never rule out what has never happened before.

This article was originally published in The Conversation and is republished here with permission.