A Spanish judge shelved the investigation into the alleged use of Pegasus spyware to hack the telephones of Spain's Prime Minister Pedro Sanchez and several of his ministers after claiming a "lack of collaboration from Israeli authorities," Spanish public broadcaster RTVE reported on Thursday.

José Luis Calama, the judge in charge of the investigation, assured that the Israeli authorities don't provide sufficient information to determine whether the alleged cyberattacks were carried out using the Pegasus software.

This is the second time the case has been shelved since 2021, when it was initially opened, with judicial authorities saying on both occasions that there is insufficient evidence to prove the alleged attack on Spanish government officials.

In this second instance, Spanish authorities obtained information from a French investigation into alleged espionage targeting the phones of journalists, lawyers, public figures, governmental and non-governmental associations, and members of the French government, including ministers and deputies, using the Pegasus software.

Calama ruled that this new insight was not useful for advancing the investigation, as the Pegasus software doesn't leave any traces beyond the amount of data extracted and sent out. This, the judge states, makes it technically impossible to assert anything about the nature of the information to which the attackers may have had access.

A man walks past the logo of Israeli cyber firm NSO Group at one of its branches in the Arava Desert, southern Israel July 22, 2021
A man walks past the logo of Israeli cyber firm NSO Group at one of its branches in the Arava Desert, southern Israel July 22, 2021 (credit: REUTERS/AMIR COHEN)

What is the Pegasus software?

Developed by the NSO Group, Pegasus exploits a number of vulnerabilities in the software, but mostly so-called "zero-day vulnerabilities."

These vulnerabilities have been given this name because they are loopholes in the software and operating systems of our devices that have not yet been discovered (hence the "zero-day") and have not been closed by the companies that produce the equipment or operating systems, such as Android by Google.

The spyware performs an action that, if someone without permission activated it, would be considered a criminal act and a violation of the law.

It is "offensive cyber" software; it does not perform defensive actions but rather offensive ones intended to compromise the existing defenses of devices and operating systems.

Yinon Ben Shushan contributed to this report.