Antiviruses can cause distress to those who use them in their device. They are aware that they are inviting an all-knowing software that sees their device's every action. It is just the trust of letting the software do its job that is keeping the software in the device and letting the owners give the permission for the software to access the device's process. For Android users, the issue is the dozens of applications that claim that they can secure your device, but in reality they are not as effective. 

The new pulished research from AV-Comparatives found out that some applications are phony. AV-Comparatives is a European company that tests numerous antivirus products, just like how its name suggests it. They surveyed around 250 antivirus applications found in the Goolge Play Store, and only 80 of them demonstrated the basic competence of a software at their jobs by detecting at least 30 percent or more of the 2,000 malicious applications AV-Comparatives gave them. The rest either failed to meet the benchmark, sometimes mistook benign applications for malware, or they have been pulled from the Play Store. In other words, they do not work. 

"In the past we and others found malicious apps, non-working apps, so it is not really a surprise to find some bogus AV apps as well," says Peter Stelzhammer, COO of AV-Comparatives. "In the times of rogue AV software, you have to be aware of everything."

But not all of them failed, some of the antivirus applications that AV-Comparatives tested did really good in blocking malicious applications, but they introduced some risks of their own. There are a lot of products, all of which share a similar user interface, which is suspicious. They relied on a whitelist approach, this means that they only named applications that were permitted to run on the device. 

The immediate ramification of that approach should be obvious: An antivirus that relies only on whitelisting will block lots of perfectly legitimate apps. In some cases, the AV-Comparatives study notes, the antivirus apps even forgot to whitelist themselves, creating an ouroboros of failure.

While Google has taken down plenty of these fraudulent apps, they still persist. It's also unclear whether Google can reasonably be expected to face down the tide. "I am not sure what to expect from Google regarding these apps," says Mohammad Mannan, a computer scientist at Concordia University who has researched antivirus software. "In general, Google as a market operator possibly cannot check all apps to verify if the apps meet their advertised obligations." Google did not comment on what protections it has in place to keep fake or faulty antivirus software out of the Play Store. Mannan argues that in some ways it would be like penalizing a boring game for claiming it was "super exciting."

The good news is that not all Android antivirus is worthless. AV-Comparatives found 23 apps that caught 100 percent of their malware samples, and several more that came close. If there's a common thread among the more reliable choices, it's that they tend to come from companies you've heard of, like F-Secure and Bitdefender and Symantec, to name a few. If you insist on installing antivirus for your Android phone, that remains your best rule of thumb.