How to remove Perseus from infected devices

What kind of malware is Perseus?

Perseus is an Android malware created using parts of previous malware (like Cerberus and Phoenix) and upgraded with new features. It lets attackers watch and control an infected device in real time. The malware includes strong protections to evade detection and analysis by security tools.

Perseus in detail

The original malware, Cerberus, had its source code leaked in 2020, which allowed other attackers to reuse and modify it. This led to the surfacing of new malware families, such as Ermac and Phoenix. Perseus is based mainly on Phoenix. There are two versions of the malware: an older one and a newer one (that is currently spreading).

One uses English in the code, while the other uses Turkish. The English version has additional development features and probably coded using artificial intelligence, while the Turkish version is simpler and more hidden.

Device evaluation and analysis evasion

Perseus checks the device to see if it is a real phone or an analysis/sandbox environment. It looks for things like root access, debugging tools, emulators, or fake device settings. It also checks for realistic features such as a SIM card, installed apps, sensors, battery behavior, Bluetooth, and Google Play Services. It then shares the results with cybercriminals to decide if the device is worth targeting.

Targeted information

Perseus has a feature that lets it read notes stored on an infected device. Unlike typical malware that focuses on stealing passwords or messages, it targets personal notes, which may contain sensitive information like passwords or financial details. In one version, it uses a command that detects note-taking apps, opens them, and goes through the saved notes.

The targeted note-taking apps include ColorNote Notepad Notes, Evernote - Note Organizer, Google Keep - Notes and Lists, Microsoft OneNote, Samsung Notes, Simple Notes, Simple Notes Pro, and Xiaomi Notes (the list may include more applications). To steal information from notes, the malware uses Android's Accessibility features.

It can move through the targeted app, tap on items, and go back. This allows it to open note apps, read the notes, and record the information without the user noticing.

Other capabilities

Perseus supports various commands. Using the malware, cybercriminals can can tap, press, type, and swipe on the screen, open apps, go back, and move through the phone (home, recent apps, scrolling, gestures). They can also type text into fields, edit text, and even wake the screen if it is off.

Furthermore, the attackers can take control of the device remotely by starting and stopping live screen sessions (VNC and HVNC) and capture screenshots to see what the victim is doing. Perseus also allows threat actors to hide activity by showing a black screen and mute the sound.

Moreover, Perseus can block or unblock apps, launch apps, and even guide the user to enable settings like installing apps from unknown sources. It can try to unlock the device using PINs or retrieve unlock information, and it can record and replay gestures.

Additionally, the malware can steal information by changing the clipboard, and accessing SMS permissions. It can send notifications, load or remove extra features, and check their status.

Conclusion

Perseus is a highly advanced Android malware that can take control of a device and steal sensitive information. Its ability to monitor, control, and hide its activity makes it especially dangerous. Victims may experience issues like financial loss and identity theft. If present on a device, Perseus should be eliminated immediately.

More examples of malware targeting Android users are BeatBanker, Massiv, and PromptSpy.

How did Perseus infiltrate my device?

Users get infected with Perseus mainly by downloading fake IPTV apps from outside official stores like Google Play. These apps are often shared as APK files, which users install manually, making it easier for the malware to spread.

Once installed, it secretly deploys the malware using a dropper to bypass Android security protections.

How to avoid installation of malware?

Download apps and software from trusted sources like official websites or app stores, and keep your operating system and apps up to date. Avoid clicking on pop-ups, ads, or links on suspicious websites, and do not accept notification requests from untrusted sites.

Be careful with unexpected emails or messages - do not open links or attachments unless you are sure they are safe. Regularly use reliable security software to scan your device and help detect or remove threats.

A dropper used to deploy Perseus (source: threatfabric.com):

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".

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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).

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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.

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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".

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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".

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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.

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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".

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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.

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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.

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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.

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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.

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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;

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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 device is infected with Perseus malware, should I format my storage device to get rid of it?

Wiping the device is one of the most effective ways to remove malware. However, this removes all data (if not backed up). It is advisable first to try removing Perseus with a tool like Combo Cleaner.

What are the biggest issues that malware can cause?

Malware can cause serious issues like stealing personal data, taking control of your device, damaging or deleting files, and leading to financial loss or identity theft.

What is the purpose of Perseus?

The purpose of Perseus is to steal sensitive information. It allows attackers to monitor the device, capture user input, and access personal data like notes, passwords, and messages. It can also fully control the device remotely and hide its activity from the victim.

How did Perseus infiltrate my device?

Users are mainly infected with Perseus by downloading fake IPTV apps from outside official app stores like Google Play. These apps are usually distributed as APK files. After installation, a dropper is used to secretly install the malware and bypass Android security protections.

Will Combo Cleaner protect me from malware?

Yes, Combo Cleaner can detect and remove most known malware infections. However, advanced malware can hide deep within the system. That is why performing a full system scan is necessary to ensure detection and removal.