How to remove the BrasDex banking malware from your Android device
Written by Tomas Meskauskas on (updated)
What is BrasDex?
BraDex is a banking malware targeting Android operating systems. This malicious program aims to gain access to victims' bank accounts and make fraudulent transactions.
At the time of writing, BrasDex targets Brazilian banking applications exclusively. In previous BrasDex campaigns, it infiltrated devices under the guise of Android system related apps. Lately, this malware has been installed by a fake Brazilian Banco Santander banking application.
Research done by ThreatFabric uncovered evidence that the cyber criminals behind BrasDex campaigns are also using the Casbaneiro trojan to infect Windows operating systems.
BrasDex malware overview
Following successful infiltration, BrasDex searches the device for targeted applications before continuing its operations. This program abuses the Android Accessibility Services to perform its malicious activities. These services are intended to provide additional aid with device interaction to users who need it.
The Accessibility Services can read the device screen, manipulate the touchscreen, interact with the keyboard, and perform other actions. Through these services, BrasDex uses the keylogging feature to record log-in credentials when victims enter them into their banking apps.
BrasDex makes unauthorized transactions, i.e., moves through windows, enters the recipients' data, etc. – automatically. The malware employs the Pix payment system for the transactions, as it allows them to be made only with the recipient's identifier, such as their email, phone number, random ID, etc. The transactions themselves raise no suspicion as they are performed using a legitimate service and straight from a user's account.
To summarize, BrasDex infections can result in severe privacy issues and significant financial losses.
If you suspect that your device is infected with BrasDex (or other malware) – immediately use an anti-virus program to eliminate it.
| Name | BrasDex virus |
| Threat Type | Android malware, banking malware, malicious application. |
| Detection Names | Avast-Mobile (Android:Evo-gen [Trj]), DrWeb (Android.BankBot.969.origin), ESET-NOD32 (A Variant Of Android/Spy.Cerberus.AY), Kaspersky (HEUR:Trojan-Banker.AndroidOS.Banbra.x), Full List (VirusTotal) |
| Symptoms | The device is running slow, system settings are modified without user's permission, questionable applications appear, data and battery usage is increased significantly, browsers redirect to questionable websites, intrusive advertisements are delivered. |
| Distribution methods | Infected email attachments, malicious online advertisements, social engineering, deceptive applications, scam websites. |
| Damage | Stolen personal information (private messages, logins/passwords, etc.), decreased device performance, battery is drained quickly, decreased Internet speed, huge data losses, monetary losses, stolen identity (malicious apps might abuse communication apps). |
| Malware Removal (Android) | To eliminate possible malware infections, scan your mobile device with legitimate antivirus software. Our security researchers recommend using Combo Cleaner. |
Android-specific banking malware examples
We have analyzed dozens of Android-targeting malicious programs; IcSpy, Drinik, AxBanker, and S.O.V.A. are just a few examples of banking malware.
Malicious software can have a wide variety of functions, which can be in different combinations. The threats posed by an infection also depend on the cyber criminals' aims. However, regardless of how malware operates – its presence on a system endangers device integrity and user safety. Therefore, we strongly recommend removing all threats immediately upon detection.
How did BrasDex infiltrate my device?
BrasDex has been observed being distributed under the guise of Android system applications and the Brazilian Banco Santander banking app.
Malware is primarily proliferated using phishing and social engineering tactics. This software is usually disguised as or bundled with ordinary apps/media.
The most widely used malware distribution methods include: drive-by (stealthy and deceptive) downloads, malicious attachments/links in spam mail (e.g., emails, SMSes, PMs/DMs, etc.), online scams, malvertising, dubious download channels (e.g., freeware and third-party websites, Peer-to-Peer sharing networks, etc.), pirated software and illegal program activation ("cracking") tools, and fake updates.
How to avoid installation of malware?
We highly recommend researching software before download/installation and/or purchase, e.g., by reading terms and user/expert reviews, checking out necessary permissions, verifying developer legitimacy, etc. Additionally, all downloads must be performed from official and verified sources.
Another recommendation is to always activate and update software using legitimate functions/tools, as illegal activation tools ("cracks") and third-party updaters can contain malware.
We also advise being vigilant when browsing since fake and dangerous online content usually appears harmless. It is just as important to exercise caution with incoming emails, DMs/PMs, SMSes, and other messages. The attachments and links found in suspicious/irrelevant mail – must not be opened, as they can be malicious and cause infections.
We must stress the importance of having a reputable anti-virus installed and kept updated. Security programs must be used to run regular system scans and to remove detected threats and issues.
Quick menu:
- Introduction
- How to delete browsing history from the Chrome web browser?
- How to disable browser notifications in the Chrome web browser?
- How to reset the Chrome web browser?
- How to delete browsing history from the Firefox web browser?
- How to disable browser notifications in the Firefox web browser?
- How to reset the Firefox web browser?
- How to uninstall potentially unwanted and/or malicious applications?
- How to boot the Android device in "Safe Mode"?
- How to check the battery usage of various applications?
- How to check the data usage of various applications?
- How to install the latest software updates?
- How to reset the system to its default state?
- How to disable applications that have administrator privileges?
Delete browsing history from the Chrome web browser:
Tap the "Menu" button (three dots on the right-upper corner of the screen) and select "History" in the opened dropdown menu.
Tap "Clear browsing data", select "ADVANCED" tab, choose the time range and data types you want to delete and tap "Clear data".
Disable browser notifications in the Chrome web browser:
Tap the "Menu" button (three dots on the right-upper corner of the screen) and select "Settings" in the opened dropdown menu.
Scroll down until you see "Site settings" option and tap it. Scroll down until you see "Notifications" option and tap it.
Find the websites that deliver browser notifications, tap on them and click "Clear & reset". This will remove permissions granted for these websites to deliver notifications. However, once you visit the same site again, it may ask for a permission again. You can choose whether to give these permissions or not (if you choose to decline the website will go to "Blocked" section and will no longer ask you for the permission).
Reset the Chrome web browser:
Go to "Settings", scroll down until you see "Apps" and tap it.
Scroll down until you find "Chrome" application, select it and tap "Storage" option.
Tap "MANAGE STORAGE", then "CLEAR ALL DATA" and confirm the action by taping "OK". Note that resetting the browser will eliminate all data stored within. This means that all saved logins/passwords, browsing history, non-default settings and other data will be deleted. You will also have to re-login into all websites as well.
Delete browsing history from the Firefox web browser:
Tap the "Menu" button (three dots on the right-upper corner of the screen) and select "History" in the opened dropdown menu.
Scroll down until you see "Clear private data" and tap it. Select data types you want to remove and tap "CLEAR DATA".
Disable browser notifications in the Firefox web browser:
Visit the website that is delivering browser notifications, tap the icon displayed on the left of URL bar (the icon will not necessarily be a "Lock") and select "Edit Site Settings".
In the opened pop-up opt-in the "Notifications" option and tap "CLEAR".
Reset the Firefox web browser:
Go to "Settings", scroll down until you see "Apps" and tap it.
Scroll down until you find "Firefox" application, select it and tap "Storage" option.
Tap "CLEAR DATA" and confirm the action by taping "DELETE". Note that resetting the browser will eliminate all data stored within. This means that all saved logins/passwords, browsing history, non-default settings and other data will be deleted. You will also have to re-login into all websites as well.
Uninstall potentially unwanted and/or malicious applications:
Go to "Settings", scroll down until you see "Apps" and tap it.
Scroll down until you see a potentially unwanted and/or malicious application, select it and tap "Uninstall". If, for some reason, you are unable to remove the selected app (e.g., you are prompted with an error message), you should try using the "Safe Mode".
Boot the Android device in "Safe Mode":
The "Safe Mode" in Android operating system temporarily disables all third-party applications from running. Using this mode is a good way to diagnose and solve various issues (e.g., remove malicious applications that prevent users you from doing so when the device is running "normally").
Push the "Power" button and hold it until you see the "Power off" screen. Tap the "Power off" icon and hold it. After a few seconds the "Safe Mode" option will appear and you'll be able run it by restarting the device.
Check the battery usage of various applications:
Go to "Settings", scroll down until you see "Device maintenance" and tap it.
Tap "Battery" and check the usage of each application. Legitimate/genuine applications are designed to use as low energy as possible in order to provide the best user experience and to save power. Therefore, high battery usage may indicate that the application is malicious.
Check the data usage of various applications:
Go to "Settings", scroll down until you see "Connections" and tap it.
Scroll down until you see "Data usage" and select this option. As with battery, legitimate/genuine applications are designed to minimize data usage as much as possible. This means that huge data usage may indicate presence of malicious application. Note that some malicious applications might be designed to operate when the device is connected to wireless network only. For this reason, you should check both Mobile and Wi-Fi data usage.
If you find an application that uses a lot of data even though you never use it, then we strongly advise you to uninstall it as soon as possible.
Install the latest software updates:
Keeping the software up-to-date is a good practice when it comes to device safety. The device manufacturers are continually releasing various security patches and Android updates in order to fix errors and bugs that can be abused by cyber criminals. An outdated system is way more vulnerable, which is why you should always be sure that your device's software is up-to-date.
Go to "Settings", scroll down until you see "Software update" and tap it.
Tap "Download updates manually" and check if there are any updates available. If so, install them immediately. We also recommend to enable the "Download updates automatically" option - it will enable the system to notify you once an update is released and/or install it automatically.
Reset the system to its default state:
Performing a "Factory Reset" is a good way to remove all unwanted applications, restore system's settings to default and clean the device in general. However, you must keep in mind that all data within the device will be deleted, including photos, video/audio files, phone numbers (stored within the device, not the SIM card), SMS messages, and so forth. In other words, the device will be restored to its primal state.
You can also restore the basic system settings and/or simply network settings as well.
Go to "Settings", scroll down until you see "About phone" and tap it.
Scroll down until you see "Reset" and tap it. Now choose the action you want to perform:
"Reset settings" - restore all system settings to default;
"Reset network settings" - restore all network-related settings to default;
"Factory data reset" - reset the entire system and completely delete all stored data;
Disable applications that have administrator privileges:
If a malicious application gets administrator-level privileges it can seriously damage the system. To keep the device as safe as possible you should always check what apps have such privileges and disable the ones that shouldn't.
Go to "Settings", scroll down until you see "Lock screen and security" and tap it.
Scroll down until you see "Other security settings", tap it and then tap "Device admin apps".
Identify applications that should not have administrator privileges, tap them and then tap "DEACTIVATE".
Frequently Asked Questions (FAQ)
My Android device is infected with BrasDex malware, should I format my storage device to get rid of it?
No, most malicious programs can be removed without resorting to formatting.
What are the biggest issues that BrasDex malware can cause?
The dangers posed by an infection depend on the malicious program's capabilities and the cyber criminals' modus operandi. BrasDex is a banking malware aiming to make fraudulent transactions. Therefore, these infections can result in severe privacy issues and significant financial losses.
What is the purpose of BrasDex malware?
BrasDex is designed to generate revenue, which is the purpose of most malicious programs. However, cyber criminals can also use malware to amuse themselves, realize personal grudges, disrupt processes (e.g., websites, services, companies, organizations, etc.), and even launch politically/geopolitically motivated attacks.
How did BrasDex malware infiltrate my Android device?
Malware is primarily distributed through dubious download channels (e.g., unofficial and freeware websites, P2P sharing networks, etc.), spam mail (e.g., emails, SMSes, PMs/DMs, etc.), malvertising, online scams, drive-by downloads, illegal software activation tools ("cracks"), and fake updates.
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