Apple has reacted to what appears to be a huge spyware campaign this week by sending warnings to iPhone owners around the world. Recipients of the warnings are advised that a “mercenary spyware attack” is attempting to remotely compromise their device.

As of Wednesday, according to TechCrunch, only two iPhone owners have publicly acknowledged receiving the warning. Italian journalist Ciro Pellegrino wrote an article about the experience Wednesday, while the Dutch activist Eva Vlaardingerbroek posted about it on X.

But this is evidently only the tip of the iceberg. In the warning message, as shared by Pellegrino, Apple reveals that the notification “is being sent to affected users in 100 countries,” making it even larger than the alert last spring which covered 92. Such attacks are deliberately alarming, with the aim of producing something akin to a chilling effect–as Vlaardingerbroek puts it, “an attempt to intimidate me, an attempt to silence me”–and most recipients would not wish to draw further attention to themselves by disclosing their involvement.

The details and motives of the attacks are unclear at this point, but so-called mercenary spyware campaigns, as the name suggests, are frequently run by private software companies to earn money from government surveillance organisations. Journalists and activists, as potential irritants to repressive governments, are two of the most common targets; as Apple’s notification explains, “This attack is likely targeting you specifically because of who you are or what you do.”

The good news for Macworld readers is that, if you haven’t received a warning–and Apple is reported to have sent out both emails and text messages to those affected–then you’ve got nothing to worry about. This appears to be an unusually large spyware campaign, but it’s still targeted at an individual level. If you have been targeted, the chances are you have powerful enemies and spyware may be quite low down on the list of your worries.

However, while it’s unlikely there is a virus on your iPhone, for peace of mind, our general advice is to keep the software on your iPhone up to date and install new versions of iOS in a timely fashion. Spyware attacks exploit vulnerabilities in iOS; once Apple becomes aware of such a vulnerability the company will patch it, and include the patch in an iOS update.

Should the worst happen, Apple offers Lockdown Mode that you can switch on if you are targeted in this way. Here’s how to use Lockdown Mode to protect your iPhone.