How Israeli firm’s ‘zero-click’ malware attack poses global security risk

Just visiting a page or refreshing an app can be enough to fall victim to a malware attack in which your personal data is stolen from a laptop or phone, researchers have found. You are not even required to “click” on anything.

An Israeli spyware firm has been found to be behind the first-known instance of “zero-click” targeted advertising in which fraudsters or spies can steal private data and send it to external servers, with Al Jazeera journalists among the victims.

In June 2025, 45 devices used by Al Jazeera staff – including several who reported on sensitive subjects – were targeted with spyware which installed itself without the need to open or download any files.

An investigation by the Canada-based academic research unit Citizen Lab, prompted by Al Jazeera’s initial internal probe into the issue, discovered that the Israeli company Candiru was behind the attacks.

Analysts say the findings are “incredibly concerning”, as they confirm the existence of a new global security threat. “We knew we were headed in this direction and now it is out in the public,” Remesh Srinivasan, professor of information studies at the University of California in Los Angeles, US, told Al Jazeera.

“This is the next level, because people are being microtargeted,” he said. “This is the point we’ve come to when it comes to surveillance.”

How ‘zero-click’ malware works

Al Jazeera’s in-house technology team first discovered unusual patterns on devices used by some journalists in 2024. Analysis of network logs provided to the Citizen Lab by Al Jazeera in 2025 provided a clear temporal signature of how the attack was executed.

Malicious advertisements were bought by Discover-Tech, an Israeli company presenting itself as a legitimate advertising firm, but which actually operates as a facilitator for mercenary spyware partners.

Its advertisement network identified Al Jazeera staff, then quietly redirected them to an infected server belonging to Candiru. The spyware firm was blacklisted by the US government in 2021, when Citizen Lab found it was responsible for the illegal hacking and surveillance of at least 100 activists, journalists and political activists across 10 countries.

Al Jazeera Media Network has condemned the targeting of its staff members’ devices and called for those responsible to be held accountable.

Cybersecurity analyst and author Eddy Willems said the advertisements used automatically infect devices the moment they pop up on the screen, but there is an important technical nuance. “Executing code inside the browser does not automatically give an attacker full control over the computer,” Willems told Al Jazeera.

“To escape the browser’s isolated environment – the ‘sandbox’ – the attacker may need a second vulnerability,” Willems said, adding that an advanced spyware operation can combine several vulnerabilities.

“The attacker attempts to exploit vulnerabilities to bypass security boundaries. This is precisely what makes this type of attack so dangerous,” the analyst said.

Once the device is infected, the malicious software is designed to collect a wide range of sensitive data, including files, documents, and browser data such as cookies, bookmarks, and saved credentials.

It can also capture keystrokes, take screenshots, record microphone and webcam input, and extract emails and messages from popular communication platforms. To avoid triggering security mechanisms, the spyware often uses encrypted communication channels and breaks up stolen data into smaller chunks sent over time.

Advertising: A new global security threat?

Analysts say Citizen Lab’s findings point to the escalation of an existing threat, which expands the scale and reach of traditional cyberattacks and makes them much harder to detect.

While “zero-click” attacks are not completely new, the findings outline a new technique through which online advertisements are used as a route to infection.

Stephen O’Shaughnessy, a lecturer in cybersecurity at the TU Dublin Blanchardstown campus in Ireland, explained that when a user opens a website or app, an automated auction sells the advertisement space in a fraction of a second. That auction shares data about the victim, including the device ID, IP address, rough location and the app or site they are on.

“Discover-Tech posed as an ordinary advertiser, used that data to find their target and win the auction for that person’s screen,” O’Shaughnessy told Al Jazeera. “Anyone with a phone or browser that shows ads can be reached, without the attacker needing their phone number or email.”

“Because no message or link is involved, there is almost nothing for the victim to notice,” he added.

Discover-Tech appeared on lists of “certified” and “approved” vendors maintained by Google and advertising industry association IAB Europe, and has served advertisements via major networks such as Google, Yandex and Beeswax.

In its report, Citizen Lab said this illustrates the structural flaws in the online advertising system, which essentially failed to detect or prevent the abuse.

Discover-Tech advertisements have popped up on devices used by personnel in national-security-sensitive networks around the world, including those of various ministries of defence, armed forces, national cyber agencies, intergovernmental organisations and media outlets, Citizen Lab found.

The research unit said these advertisements have also appeared on networks used by the United Nations, NATO, the European Parliament, the European Commission and the Council of the European Union’s General Secretariat.

‘Almost nobody was watching’

Government networks have also been targeted in at least 24 countries, including the United States, Italy, Denmark, Norway, Australia, Russia, Mexico and Israel itself. Networks of media organisations have also been targeted, mainly in Australia, Denmark and Sweden, according to Citizen Lab.

In a separate report, New York-based advertising security firm Confiant said its own investigations had found that some of Discover-Tech’s advertisements also appeared in critical networks used by the Pentagon, the United Nations International Atomic Energy Agency and the International Criminal Court.

O’Shaughnessy said infection has not been confirmed there – only profiling of users. “But that alone is concerning, he said. “The ad system was built to send code from strangers to billions of screens with pinpoint targeting. Almost nobody was watching it from a security angle.”

The analyst said the risk remains low for most people as these attacks are expensive and aimed at specific targets. “For individuals at high risk, like journalists and officials, the best first defence is to install an ad blocker, switch off their advertising ID through their phone’s privacy settings, keep everything updated, and turn on Lockdown Mode or Android’s Advanced Protection,” he said.

Precautions also need to be taken within the industry and at government level. “To combat this, the ad industry needs to properly vet who’s buying ads,” O’Shaughnessy said, while “regulators need to stop personal data being sprayed out to thousands of unknown bidders in every auction.”