The Israeli army’s elite cyber warfare unit is using Microsoft’s cloud servers to store masses of intelligence on Palestinians in the West Bank and Gaza — information that has been used to plan deadly airstrikes and shape military operations, an investigation by +972 Magazine, Local Call, and the Guardian can reveal. 

Unit 8200, roughly equivalent in function to the U.S. National Security Agency (NSA), has transferred audio files of millions of calls by Palestinians in the occupied territories onto Microsoft’s cloud computing platform, Azure, operationalizing what is likely one of the world’s largest and most intrusive collections of surveillance data over a single population group. This is according to interviews with 11 Microsoft and Israeli intelligence sources in addition to a cache of leaked internal Microsoft documents obtained by the Guardian. 

In a meeting at Microsoft’s headquarters in Seattle in late 2021, the then-head of Unit 8200, Yossi Sariel, won the support of the tech giant’s CEO, Satya Nadella, to develop a customized and segregated area within Azure that has facilitated the army’s mass surveillance project. According to the sources, Sariel approached Microsoft because the scope of Israel’s intelligence on millions of Palestinians in the West Bank and Gaza is so vast that it cannot be stored on military servers alone. 

Microsoft’s immense storage and computing power capabilities enabled what multiple Israeli sources described as the project’s ambitious goal: to store “a million calls an hour.” 

Following the 2021 meeting, a dedicated team of Microsoft engineers began working directly with Unit 8200 to build a model that would allow the intelligence unit to use the American company’s cloud services from within its own bases. According to one intelligence source, some of these Microsoft employees were themselves alumni of Unit 8200, which made the collaboration “much easier.”

According to the Guardian’s reporting, the leaked documents suggest that 11,500 terabytes of Israeli military data — equivalent to roughly 200 million hours of audio — were being stored on Microsoft’s servers in the Netherlands by July of this year, while smaller portions were being stored in Ireland and Israel. It is not possible to tell how much of this data belongs specifically to Unit 8200; as a previous investigation by +972, Local Call, and the Guardian revealed earlier this year, dozens of Israeli army units have purchased cloud computing services from Microsoft, and the company has a footprint in all major military infrastructures in Israel. 

The leaked documents further reveal that before the current Gaza war, Microsoft’s leadership viewed the cultivation of the company’s relationship with Unit 8200 as a lucrative business opportunity and characterized it internally as “an incredibly powerful brand moment” for Azure. Nadella himself, during his 2021 meeting with Sariel, defined the partnership as “critical” for Microsoft, and committed to providing the resources to support it.

Microsoft has said publicly that it found “no evidence” that its technology was used to harm Palestinians in Gaza, and a spokesperson told us in response to this investigation that the company was unaware that its products had been used to aid the surveillance of civilians. But three Israeli intelligence sources stated that Unit 8200’s cloud-based intelligence trove has been used over the past two years to plan lethal airstrikes in Gaza, and that it often serves as a basis for arrests and other military operations in the West Bank.

‘Tracking everyone, all the time’

Sariel’s interest in upgrading Israel’s mass surveillance infrastructure dates back to 2015, when he was an intelligence officer in Israel’s Central Command. That year witnessed a wave of “lone-wolf” stabbing attacks in the West Bank, Jerusalem, and inside the Green Line — many of them carried out by Palestinian teenagers previously unknown to the security services, making the attacks particularly difficult to thwart.

“We found ourselves going … from funeral to funeral,” Sariel recalled in a book he published about artificial intelligence in 2021, the year he took over as head of Unit 8200 (he resigned last year).

“[A Palestinian] decides to perpetrate an attack using a kitchen knife to stab a victim, or the family vehicle to run people over,” he wrote. “Sometimes the person doesn’t even know a day before that he or she is going to commit such an attack. In these cases, traditional intelligence agencies are helpless. How can such an attack be predicted or prevented?”

Sariel’s solution, according to an intelligence officer who served under him at the time, was to start “tracking everyone, all the time.”

Over the next few years, he led a large-scale, well-funded project that dramatically expanded Israel’s surveillance of Palestinians and integrated multiple intelligence databases. “Suddenly, the public became our enemy,” another source who served in the unit under Sariel said.

In his book, Sariel wrote about the need for intelligence agencies to “migrate to the cloud” to deal with the problem of how to store increasingly vast amounts of data. +972 and Local Call previously revealed that the Israeli army has also used Amazon’s cloud computing platform, AWS, to store internal military data.

Sariel saw the collaboration with Microsoft as a breakthrough specifically because it would enable the mass storage of audio files. Multiple sources used the word “infinite” to describe the project’s scale.

Beforehand, Unit 8200 could store the calls of tens of thousands of Palestinians defined as “suspects” on its internal servers. The unit also developed a system called “noisy message,” which collects Palestinians’ text messages and assigns each of them a rating indicating their level of “danger.” But with the help of Azure, Unit 8200 was able to begin storing the calls of millions of Palestinians, vastly expanding its pool of data.

A senior source in Unit 8200 explained that Sariel viewed his relationship with Nadella, the Microsoft CEO, as a tool to advance “revolutions” in mass surveillance of Palestinians. “Yossi bragged a lot, even to me, about his connection with Satya,” the source said. (In response to this investigation, a Microsoft spokesperson stated that Nadella was only present in the 2021 meeting for 10 minutes, and that their only further contact was a condolence card Sariel sent after the death of Nadella’s son.)

Not everyone in the unit looked favorably on this partnership. One source familiar with the project said it was significantly more expensive to transfer data to Microsoft’s servers than it would have been to purchase servers and processors independently. Others in the unit felt uncomfortable about storing sensitive information overseas. But Sariel insisted, making clear his excitement for the project’s potential.

“For Yossi, ‘cloud’ and ‘Microsoft’ are buzzwords,” one intelligence source said. “He sold it internally and that’s how he got a huge budget. He said it was the solution to our problem in the Palestinian arena, and that this was the future.”

‘This isn’t leaving Azure anytime soon’

By early 2022, engineers from Microsoft and Unit 8200 were working quickly and closely to design a special model within the cloud that would be carefully tailored to the unit’s needs. “The rhythm of interaction with [8200] is daily, top down and bottom up,” one internal document noted.

As part of its effort to migrate vast amounts of its surveillance data to the cloud, the leaked documents reveal, Unit 8200 was prepared to “push the envelope” on the types of data it was willing to store on Azure. A significant portion of the raw intelligence was expected to reside initially in Microsoft data centers outside of Israel. But Israel’s Justice Ministry and Finance Ministry raised concerns about potential lawsuits against cloud service providers abroad, which could force them to hand over stored data if it was suspected of being used to violate human rights.

An internal legal opinion from the Justice Ministry in 2022 noted that both France and Germany required corporations to check for human rights violations in their supply chains by law. If it were to be revealed that these corporations are operating in the occupied Palestinian territories, such laws “may lead to the issuance of orders to prevent or restrict services” to Israel, it noted. The ministry warned that the Netherlands was working on similar legislation. 

Since cloud service providers are “some of the largest and most powerful companies in the world,” one Justice Ministry document warned, a potential lawsuit would be particularly harmful to Israel. Despite these concerns, Unit 8200’s partnership with Microsoft continued, spearheaded by Sariel himself.

After Israel launched a war on the Gaza Strip in the wake of Hamas’ October 7 attack, it soon became clear that the enclave would remain under Israeli military control for a significant period. As a result, an intelligence officer explained, internal enthusiasm for storing mass surveillance data from Gaza on the cloud-based system increased. 

“[The army] understood that this is also needed in Gaza — that we’re heading toward long-term control there, like in the West Bank,” the source explained. “This [surveillance repository] isn’t leaving Azure anytime soon. It’s a huge project.”

Several sources insisted that the project has “saved Israeli lives” by preventing Palestinian attacks. “You hear [someone say], ‘I want to become a martyr,’ and you feel reassured, as a security officer, that this stuff is being picked up by our system,” one officer said.

But such blanket surveillance allows Israel to find potentially incriminating information on virtually any Palestinian, which can be used for all manner of purposes — including blackmail, administrative detention, or retroactively justifying killings. 

“These people get entered into the system, and the data on them just keeps growing,” an intelligence officer who recently served in the West Bank explained. “When they need to arrest someone and there isn’t a good enough reason to do so, [the surveillance repository] is where they find the excuse. We’re now in a situation where almost no one in the [occupied] territories is ‘clean,’ in terms of what intelligence has on them.”

‘Serious allegations of complicity in genocide’

In internal documents from 2023, Microsoft estimated that the partnership with Unit 8200 would generate hundreds of millions of dollars for the company over five years. It noted that the unit’s leadership hoped to multiply the amount of data it stores in Microsoft’s servers “tenfold” over the next few years. 

But media reports of Microsoft’s complicity in Israel’s onslaught on Gaza — including the revelation by +972 and Local Call that the company’s cloud and artificial intelligence sales to the Israeli military skyrocketed during the war — have increased pressure on the company from the public as well as from its own employees. 

In one highly publicized incident at the company’s annual conference in May, a Microsoft engineer interrupted Nadella’s keynote speech. “Satya, how about you show how Microsoft is killing Palestinians?” he shouted. “How about you show how Israeli war crimes are powered by Azure?”

Against this backdrop, 60 Microsoft investors, collectively holding shares worth $80 million, approached the company in July with a demand to review its monitoring and oversight mechanisms for customers who misuse AI tools, “in the face of serious allegations of complicity in genocide and other international crimes.”

Responding to the mounting pressure, Microsoft announced that it had conducted a review of whether its sales to Israel’s Defense Ministry had led to human rights violations. According to the statement, Microsoft provided “limited emergency support” to the Israeli army in the aftermath of October 7 to “help rescue hostages.” The company emphasized that there is “no evidence to date” that the military used Azure to “harm people in the conflict in Gaza,” stressing that Microsoft’s support didn’t violate “the privacy and other rights of civilians in Gaza.” 

Yet the internal documents detailing Microsoft’s partnership with Unit 8200 paint a different picture of the company’s concern for Palestinians’ privacy. In fact, Palestinians were not mentioned in the documents summarizing the 2021 meeting between Sariel and Nadella, which also involved Israeli intelligence officers and senior Microsoft executives. 

According to the Guardian’s reporting, Unit 8200 informed Microsoft of its intention to transfer up to “70 percent” of its data, including secret and top secret data, to Azure. And while the project’s ultimate goal (beyond “deepen[ing] the partnership”) does not appear to have been explicitly stated, an intelligence source said that executives of Microsoft’s Israeli subsidiary — who worked closely with Unit 8200 personnel on the project — were given clearer indications.

“Technically, they’re not supposed to be told exactly what it is, but you don’t have to be a genius to figure it out,” the source noted. “You tell [Microsoft] we don’t have any more space on the servers, that it’s audio files. It’s pretty clear what it is.” 

In response to our investigation, a Microsoft spokesperson stated: “Microsoft’s engagement with Unit 8200 has been based on strengthening cybersecurity and protecting Israel from nation state and terrorist cyber attacks. This was the purpose of the meeting in November of 2021 and, in addition to our standard commercial relationship, is the basis of our ongoing relationship with the 8200 Unit. 

“The leadership of Unit 8200 was interested in assessing security protection for data in our Azure public cloud offering,” the spokesperson continued. “We offer specific protections to numerous customers in retail, financial services and consulting organizations, as well as governments. Unit 8200 was interested in and tested this security; this was not a ‘secret’ or tented project. 

“At no time during this engagement or since that time has Microsoft been aware of the surveillance of civilians or collection of their cell phone conversations using Microsoft’s services, including through the external review it commissioned,” the spokesperson went on. “Any allegations about Microsoft leadership involvement and support of this project … are false.” 

The IDF Spokesperson stated that “the coordination between the Defense Ministry and the IDF with civilian companies is conducted based on regulated and legally supervised agreements,” adding that the army operates “in accordance with international law, with the aim of countering terrorism and ensuring the security of the state and its citizens.”

Yossi Sariel declined to comment, referring us to the IDF Spokesperson.

Harry Davies of the Guardian contributed to this report.