Avast Mobile Security has more than 100 million installs in Google Play and a solid 4.5 user rating, and it was our Editor's Choice for Best Android Security App in 2014 and 2015. We liked its huge assortment of powerful anti-theft and privacy tools (including some for rooted phones only), and its excellent, if not quite perfect, malware-detection rate.
In January 2016, Avast Mobile Security moved from a freemium model (it was originally $14.99 per year to unlock all the features) and became a purely free app, supported by ads. Avast still offers one of the most comprehensive and customizable feature sets in the Android antivirus market. But its malware-detection rate is inconsistent, its system impact is heavy, and some of its formerly best features, such as a backup option and a locate function for rooted phones that survived a factory reset, have been discontinued.
We still recommend Avast Mobile Security as the best free Android antivirus solution. But if you're willing to pay, Bitdefender Mobile Security is your best bet.
Costs and What's Covered
The core Avast Mobile Security app is free. Avast doesn't state which versions of Android the app supports, but the Google Play page said the Avast app supported every Android device we've ever owned.
Avast breaks out many features into separate apps with varying pricing schemes. Its Anti-Theft, Battery Saver, Cleanup & Boost system optimizer and Wi-Fi hotspot finders are free. The Avast Passwords password manager is mostly free, but you'll have to pay for a couple of higher-level functions.
Avast SecureLine, a virtual-private-network (VPN) client, is $20 per year per mobile device. A seventh add-on app, Avast App Locker, replicates a feature built into Avast Mobile Security, but adds fingerprint and pattern-lock support.
You don't need to have Avast Mobile Security installed to use any of these add-ons, but most of them integrate well with the core app.
The breadth of features in Avast Mobile Security and its ancillary apps have garnered it the most attention, but the app does perform fairly well at its core function of protecting the user from malware. It can be set to scan your device at a specific time each day; alternately, you can simply rely on manual scans.
Avast's Web Shield supports not only the native Android browser and Chrome, but also Amazon's Silk browser, Boat Browser and Boat Browser Mini. There's "experimental" support for Dolphin Browser Mini. In my tests, Avast Mobile Security successfully detected and blocked several known phishing sites.
Avast performs a number of scans on apps as they are installed or updated. It will warn you if other Avast users have reported an app as malicious or troublesome, and will also detect potentially unwanted programs such as adware or phony system optimizers.
Avast Mobile Security finished slightly below average in German independent lab AV-TEST's most recent evaluations of Android security products, conducted in July 2016. It stopped 99.5 percent of the 3,459 samples of brand-new malware it encountered, and 99.7 percent of the 3,367 pieces of malware discovered in the previous four weeks.
Both scores are a notch below the average detection rates for the 26 products tested in July, which were 99.6 percent for new malware and 99.8 for the slightly older samples.
Of the six Android antivirus apps we reviewed in 2016, Avast Mobile Security was dead last. Norton Mobile Security and Bitdefender Mobile Security got perfect, 100-percent scores in both categories, followed by Kaspersky Internet Security (99.9/100 percent), ESET Mobile Security (99.9/99.9 percent) and CM Security (99.7/100 percent).
Arguably, Avast just had a bad month, as its scores in previous AV-TEST evaluations were somewhat better. In May 2016, it got 99.5/99.9; in March, 99.9/99.9; in January, 99.2/99.9. More significantly, Avast's scores beat the average in all three rounds.
But Avast's scores fluctuate a lot. Over the past year of AV-TEST's bimonthly Android evaluations, Avast's detection rates ranged from 98.1 percent to 100 percent. (CM Security's scores were even more volatile, bottoming out at 97.5 percent.) Here's a chart to illustrate this:
In contrast, Bitdefender, ESET, Kaspersky and Norton all had consistent scores in the past year, never dipping below 99.8 percent. In Bitdefender's case, you'd have to go back to May 2015 to find anything as low as 99.9.
Security Features and Tools
As mentioned, already, Avast breaks out many features commonly included with Android security products into separate apps. There's no anti-theft function in Avast Mobile Security — instead, you'll have to download and install the free Avast Anti-Theft.
All the stand-alone apps work well with Avast Mobile Security, and once installed, can be directly accessed from it. We'll first examine the built-in features, then the add-ons.
Built-In Security Features
Wi-Fi Check (not the same as the stand-alone Avast Wi-Fi Finder app) scans the local network to determine its safety and desirability, based on the router, password, encryption and connectivity. My home network was deemed safe, but Avast was less than thrilled with the unencrypted network at a nearby Starbucks.
App Locking is one of Avast Mobile Security's most bare-bones features. It's a simple list of your apps, with a toggle switch next to each that flips between locked and unlocked. If you lock one, you'll have to enter a four-digit PIN to open it.
I found that when I clicked on a locked app, it would often be visible (but not usable) for a few seconds before the PIN lockscreen appeared. That defeats some of the privacy purposes of an app lock. I was also disappointed that I couldn't use a pattern or a fingerprint to lock and unlock apps. (The stand-alone Avast App Locker app supports fingerprints and patterns.)
Call Blocker lets you blacklist numbers or categories of numbers. I had very poor luck with this feature in real-world use, and could successfully block only specific area codes. On the bright side, this page was a well-crafted example of Google's Material Design aesthetic, so if keeping only 800 and 877 numbers at bay is enough for you, this can get the job done in style.
Privacy Advisor is another list of your installed apps, here grouped into three permissions categories: High, Medium and Low. Clicking an app shows you the permissions the app requires, plus the ad networks that feed into it. This provides more information than the built-in app viewer, but you'll need to click each app to view the relevant data.
Avast has quietly brought back the two-way system firewall that it discontinued when Avast Mobile Security went completely free. Unfortunately, the firewall works only on rooted Android devices. We weren't able to test it, even on a theoretically rooted OnePlus One running Cyanogen OS.
Avast Cleanup (called Cleanup & Boost in the Google Play store) is the only add-on app that gets its own screen in the Avast Mobile Security core app. It displays the percentage of used space on your device. Tapping Open Cleanup takes you to the standalone app.
Cleanup, as you might guess, is an optimizer designed to maximize available storage space on your device. Its Advanced Cleaning section sorts items by size or usage to help you quickly jettison anything you aren't using regularly. The Boost function shuts down running apps to free up memory.
I found it particularly odd for Avast not to have integrated its anti-theft functions into the main app. Nearly all antivirus apps, and even the Android OS itself, have some anti-theft component, and it feels strange to have to set this up separately. However, the Avast Anti-Theft app offers many more features than most anti-theft functions, and is one of the best we've ever seen. But again, you don't need Avast Mobile Security to get it.
The setup process isn't the most intuitive. You have to create a PIN for SMS commands, grant the app a ton of system permissions and set up an account with my.avast.com, if you haven't already done so. The web portal lets you initiate the Anti-Theft features remotely.
The number of options and toggles available in Avast Anti-Theft can be overwhelming. They let you locate the device, lock it down, wipe its data or even make the device say through the speaker, "This phone has been lost or stolen," followed by a loud siren. All can be done through the web portal or via SMS.
If the SIM card is changed, or if you flag the device, the phone can initiate tracking, lock the device, turn on the siren, prevent USB debugging and prevent the data connection from being disabled.
You can also geofence the phone, which is helpful if you know you'll be at a coffee shop for a few hours and need to use the bathroom. The lost mode will be triggered if the phone is removed from an area you designate.
From the web portal, Avast users can forward all calls and texts to a new number, launch the Anti-Theft app on the device, record audio, take a picture, get data, send a pop-up message that will take over the screen when turned on, or have the device send its location periodically.
Most anti-theft features worked within seconds, but I had some connectivity issues with the web portal. Sometime, it couldn't find the device, even though both my laptop and the phone were operating on the same Wi-Fi network.
Unfortunately, Avast has killed Anti-Theft's truly unique feature: When installed on rooted devices, it could formerly survive a hard reset that wiped the rest of the device's data and restored factory settings. A factory reset is the first thing a professional phone thief would do with a stolen phone. No other Android security app offered this.
But Avast Anti-Theft still does much more than the built-in anti-theft components offered by other antivirus brands, many of which don't improve upon the stock Android Device Manager. And you can install it alongside any antivirus app for free.
Avast Battery Saver lets you fine-tune power profiles to maximize battery life, such as by shutting off Wi-Fi or Bluetooth. I tested a number of different power profiles, and all worked as expected. The location-based settings were especially useful, as my schedule is fairly unpredictable but my needs at specific locations are fairly predictable.
With Avast Passwords, you create a single highly secure master password, then enter the rest of your passwords into the app. From then on, you won't need to remember anything but the master password.
The basic version of Password is free and includes secure encryption, syncing between devices, automatic form-fill and the ability to generate complex and unique passwords. The premium version costs $9.99 a year, but the only relevant additional feature is Password Guardian, which tells you if one of your accounts (Gmail, Amazon, etc.) has been hijacked.
The Avast SecureLine VPN client is now the lone paid-only mobile service from Avast; it's $1.99 a month or $19.99 a year, per device. SecureLine has a competitive feature set, but if you have more than one mobile device you'd like to protect (it works on iOS as well), I would recommend looking elsewhere. There are plenty of solid VPN offerings that cover multiple mobile devices for $20 a year or less.
With unlimited cellular data plans mostly a thing of the past, the ability to find an open Wi-Fi network is valuable. Avast Wi-Fi Finder shows the location of networks near you. It can activate SecureLine VPN anytime you connect to Wi-Fi (which we strongly recommend). I wouldn't use Wi-Fi Finder every day, but I was impressed with its hotspot-finding abilities.
As mentioned above, there's a stand-alone App Locker app, but except for its pattern-lock and fingerprint support, it's no different from the built-in applock feature.
To gauge the system impact of running Avast Mobile Security, I ran multiple tests using the Geekbench 3 benchmarking tool on my Nexus 6P running Android 6.0.1. Following installation of the app, the phone scored 1.1 percent higher than its baseline average; during a full scan, it scored 24.9 percent below the baseline.
These results placed Avast Mobile Security in last place among the six Android antivirus products we tested, with by far the heaviest system impact during full scans. Norton Mobile Security was the only product that finished near Avast, with the rest of the apps finishing well ahead of these two.
Setup and Support
The download from Google Play went quickly over Wi-Fi and the install was fast until I ran into the initial device scan, which took just over 2 minutes. Setting up the rest of the core app — which included Wi-Fi Check, App Locking, Call Blocker and Privacy Advisor — took another 5 minutes.
But the core functionality was just the tip of the iceberg. Downloading, installing and configuring the seven add-on apps took me another 20 minutes.
It is entirely up to the user whether he or she wants any of these extras. The launcher screen merely lists the other Avast apps that are available, which are greyed out if not installed. However, you will see native ads following a scan, which, irritatingly, continue to show ads for these extra apps even if you do install them.
Support for Avast Mobile Security is available through the Settings screen and relies on a list of FAQs, user forums (which appear to be well-moderated by Avast) and finally email support. There's no telephone support.
The user interface for Avast Mobile Security is fantastic. The designers have clearly embraced Google's Material Design guidelines, and the minimalistic aesthetic is very friendly to new users. Unfortunately, this really applies only to the core Avast Mobile Security app.
The add-on apps definitely have taken cues from Material Design, but don't look like the same family of products. They are entirely dark-themed, whereas Avast Mobile Security has an abundance of blue sky and green hills. There are also just too many settings in the extra components. Some of the features and options just aren't that obvious, and there is little to explain them.
The new ad-supported business model for Avast Mobile Security is somewhat concerning, both for the possible performance hit it creates and because the ad-distribution channel is a potential malware attack vector. Avast says it carefully vets the ad content, and, indeed, I typically saw only two ads, for the same content, at the top and bottom of every scan result.
One feature I would love to see Avast add soon is fingerprint support. With all of the varied Avast add-on apps, I ended up with four distinct PINs and passwords to access different functions. It would have been easier to use a single fingerprint.
Avast's malware detection is inconsistent, but acceptable; its system impact is heavy; and it no longer offers some unique functions for rooted devices. But Avast Mobile Security remains a compelling option for those who value flexibility at a bargain price.
The other completely free app we reviewed, CM Security, had better malware-detection scores in the latest round, but not over the long run. CM Security does offer fingerprint login, which makes a huge difference on a device that supports it.
However, if you're willing to pay for Android malware protection, or get it as part of a multi-platform antivirus bundle, we recommend Bitdefender Mobile Security or Norton Mobile Security.