A security flaw in WhatsApp can be, and has been, exploited to inject spyware into victims’ smartphones: all a snoop needs to do is make a booby-trapped voice call to a target’s number, and they’re in. The victim doesn’t need to do a thing other than leave their phone on.
The Facebook-owned software suffers from a classic buffer overflow weakness. This means a successful hacker can hijack the application to run malicious code that pores over encrypted chats, eavesdrops on calls, turns on the microphone and camera, accesses photos, contacts, and other information on a handheld, and potentially further compromises the device. Call logs can be altered, too, to hide the method of infection.
Engineers at Facebook scrambled over the weekend to patch the hole, designated CVE-2019-3568, and freshly secured versions of WhatsApp were pushed out to users on Monday. If your phone offers to update WhatsApp for you, do it, or check for new versions manually.