The discovery that hackers could snoop on WhatsApp should alert users of supposedly secure messaging apps to an uncomfortable truth: end-to-end encryption sounds nice, but if anyone can get into your phone’s operating system, they will be able to read your messages without having to decrypt them.

According to a report in the Financial Times on Tuesday, the spyware that exploited the vulnerability was Pegasus, made by the Israeli company NSO. The malware could access a phone’s camera and microphone, open messages, capture what appears on a user’s screen and log keystrokes, rendering encryption pointless. It works on all operating systems, including Apple’s iOS, Google’s Android and Microsoft’s rarely used mobile version of Windows.

The cybersecurity community has known about it for years, and activists have been raising hell about its use against dissidents and journalists in dozens of countries — although NSO itself says it doesn’t sell Pegasus to unsavoury regimes and that it is disabled in the US.

It was previously assumed that for Pegasus to work, the intended victim had to click on a phishing link to install the malware. But according to a brief technical description of the hack posted by WhatsApp’s owner, Facebook, it now appears hackers can install the malware simply by calling the target.

This isn’t the first vulnerability of this kind to be discovered in a supposedly secure messaging app. Last year, Argentinian security researcher Ivan Ariel Barrera Oro wrote about a flaw in Signal, an app favoured by Edward Snowden. In that case, a hacker could send a specially crafted Internet address in a Signal message and it would download the malware.

Any channel

It’s important to realise, however, that spyware that can install itself without any action on the user’s part can arrive through any channel, be it an encrypted messenger, a browser, an e-mail or SMS client with an undiscovered vulnerability allowing such an attack.

These are merely applications running on top of an operating system, and once a piece of malware gets into the latter it can control the device in a multitude of ways. With a key logger, a hacker can see only one side of a conversation. Add the ability to capture a user’s screen, and they can see the full discussion regardless of what security precautions are built into the app you are using.

“End-to-end encryption” is a marketing device used by companies such as Facebook to lull consumers wary about cyber-surveillance into a false sense of security.

The tug of war between tech firms touting end-to-end encryption as a way to avoid government snooping and state agencies protesting its use is a smokescreen. Government and private hackers are working feverishly on new methods to deploy malware with operating system-wide privileges. Companies such as NSO are at the forefront of this important work, which can help catch terrorists and prevent attacks — or imprison dissidents and disrupt revolutions against dictatorial regimes.

The WhatsApp episode is likely to increase the backlash against NSO and the export licence it has from the Israeli government to sell Pegasus. But if this particular firm stops developing the malware, others will take its place.

The hard truth for activists and journalists in need of secure messaging is that the more tech-savvy they are, the safer they can make their digital communications. One can, for example, encrypt messages on a non-networked device before sending them out through one’s phone. But even that wouldn’t guarantee complete security since responses could be screen-captured.