The online group Anonymous and other protesters have barraged Israel with more than 60 million hacking attempts, according to the finance minister, Yuval Steinitz.
To counter the threat, Steinitz said, the government is working in "emergency mode." He claimed all but one of the attacks has been fended off, and that one knocked a website offline for only 10 minutes.
Anonymous - the multifaceted movement of online rebels and self-described "hacktivists," spearheaded the campaign against Israel, distributing press releases and videos denouncing what it described as an "insane attack" against Gaza. The cyber onslaught began after Israel launched airstrikes against Gaza last week following persistent rocket fire.
Others have joined into what has effectively become a free-for-all attack on Israel. One group, which called itself the Pakistani Cyber Army, claimed responsibility for having hijacked roughly two dozen Israeli-registered sites, including one belonging to Coca-Cola.
One of its members, who identified himself only as a Pakistani Muslim, told The Associated Press that more was on the way.
"We won't stop until they stop killing innocent kids and people," he said.
Much of the online onslaught has come in the form of denial-of-service attacks, a technique that works by overloading a website with traffic.
Tel Aviv-based security company Radware said the attacks against Israel first began surging across the web on Thursday, describing some as well coordinated denial-of-service attacks. Although such attacks can effectively knock their targets off the web, they're usually temporary and rarely do lasting damage.
Radware said the targets included the Israel Defense Forces, the prime minister's office, Israeli banks, the Tel Aviv city government, airlines, infrastructure and business sites.
Ronen Kenig, a Radware analyst, said the flow of rogue traffic wasn't as powerful as attacks that hit the U.S. banking sector two months ago.
"In terms of the amount of traffic, it's not massive," he said, explaining that the attackers were yet to draw on networks of infected computers known as botnets to mount their attacks. Botnets are amassed by hackers and can grow to include thousands of compromised computers, giving them much more firepower than a few dozen online activists acting in tandem.
Government sites aren't the only ones targeted. Many other apparently randomly chosen Israeli sites have been hit, including an Israeli massage parlor, an obscure luxury car site, an accountancy practice and a university website.
Erel Margalit, chairman of Jerusalem Venture Partners, a leading Israeli venture capital firm, has invested significantly in Israel's cybersecurity system but said more must be done.
"Israel has the Iron Dome system (to intercept incoming rockets), but it needs a cyberdome," he said, noting the government just approved collaboration on the first-ever private cybersecurity incubator to further invest in the industry.
"The start-up nation is also a cybernation, it needs to be defended, and Israel is known to be quite advanced in this field," he said. Israel is often called the start-up nation because of its technology companies.
Kenig said his company had seen evidence the attackers were ramping up their efforts.
Technolytics Institute, a private U.S. consultancy, said Israel is prepared to confront incoming threats, rating Israel as fourth behind Russia, China, and the U.S. for cyberintelligence capabilities not just defensive, but offensive, as well.
Kevin Coleman, senior fellow at Technolytics, said while Israel has invested significantly in the industry, Anonymous has become a new, threatening "virtual state" of sorts.
"When you think about conflict in general, you think about borders, but the internet doesn't have borders," he said. "So how do you retaliate against a loose coalition? How do you negotiate a cease-fire with Anonymous? We're at the tip of the iceberg in figuring out how to deal with virtual states and creating a new paradigm," he said.
"We need to do it quickly, though. This is the warfare of the future."
By the numbers
• More than 100 Palestinians, half of them civilians, have been killed, according to Palestinian medical officials. Three Israeli civilians have died from rocket fire.
• Israel has attacked more than 1,350 targets in the current offensive, according to the Israeli army. Hamas and smaller armed groups have responded with nearly 600 rockets, the army says.
• Israel says its new "Iron Dome" rocket-defense system has shot down more than 300 incoming projectiles.