Facebook-owned WhatsApp on Friday agreed with the strong demand made by the Indian government to “explain the kind of breach” to safeguard the privacy of millions of citizens, who may be prone to a cyberattack, which apparently only needed a missed call to install the spyware.

NSO Group limits sales of Pegasus spyware to state intelligence agencies and others. The software has the ability to collect confidential data from a target device. Pegasus can be installed on devices as “exploit links.” The Indian government has denied purchasing or planning to buy Pegasus from NSO Group, in response to allegations from rival parties.