The cyberattack crashed through several Israeli government sites on Monday, according to state officials online.
The Israel National Cyber Directorate has blamed the closure of the service over a DDoS attack. Such incidents often involve external attackers directing untrue traffic waves on a website, making it temporarily inaccessible.
Health, justice and social services have been affected, as well as the prime minister’s office, according to Haaretz, quoting a source describing the incident as the worst ever to strike Israel.
Communications Minister Yoaz Hendel convened a meeting with officials in his office, and communications companies took steps to restore normalcy.
Access to websites was restored later on Monday.
The attack affected websites using the “.gov.il” domain, which is used on all government websites except for those related to security, security officials said.
Officials did not immediately say who may be behind the attack.
Mike Sexton, an expert on cyber and Middle East policy, called this type of attack a denial of service as absurd, but something that still needs significant resources.
“Israel and Iran have recently participated in a low-level cyber-tit-for-tat program, so Iran is an obvious source of explanation, but we should not come to conclusions,” Mr Sexton told the National.
“Iran has a lot of power, so I think it would be unusual for them to use this kind of ancient attack.”
He noted that Israel has now taken steps to support the Russian-led international sanctions regime, which had previously been neutral and acted as a mediator between Russia and Ukraine.
“This type of attack is a feature of the Russian extremists. We saw them use this type of attack against the Estonian government in 2006,” he said.
Gil Messing, a spokesman for Israel-based Check Point Software Technologies, said there was little chance of significant damage.
“This is usually done to send a message and make a lot of noise. It is not really the entry or acquisition of information, ”he told Bloomberg.