Cybersecurity researcher Lukas Stefanko, who studies malware at security firm ESET, discovered that the app ‘Squid Wallpaper 4K HD’ was being used to infect Android phones with the notorious Joker malware.

While the Joker malware has been around for some time, and has even been spotted on Google Play Store earlier, this is the first instance of a Squid Game-based app being used to spread it.

As per Stefanko’s post, the app had been installed more than 5,000 times before it was identified and taken down. The app could download and execute native libraries and even execute APK payloads, the security researcher noted in his post. This could be used to install the Joker malware on devices.

Stefanko warned that the flagged app allowed hackers to carry out “malicious ad-fraud and/or unwanted SMS subscription actions”. This means infected devices can be bombarded with unwanted advertisements through text messages. Cybercriminals could also sign up affected users for some premium services, which can cost them a lot of money.

While the app has been removed from the Play Store, users who had installed the app on their device continue to be at risk. They must uninstall the app immediately to remove the threat of being targeted.

Stefanko noted that there are more than 200 apps based on Squid Game available on Google Play. The most downloaded out of these apps reached one million downloads within 10 days.

“Seems like a great opportunity to make money on in-app ads from one of the most popular TV show without official game,” he stated.

Considering how cybercriminals can use such opportunities to trick people into giving access to their devices, users need to be very cautious while installing applications on their devices. Make sure that the apps you download come from official or authorised sources. Never download apps from unauthorised sources or app stores to keep your devices safe.