Threat Explorer

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23 July 2014
06 August 2015
Infection Length:
Systems Affected:
Android.Simplocker.B is a Trojan horse for Android devices that may encrypt files on the compromised device. It then asks the user to pay in order to decrypt these files.

Android package file
The Trojan may arrive as a package with the following characteristics:

Package name:
Version: 1.0

Once installed, the application will display an icon of a white lower case F on a red background above the text Video Player.

For more information see our blogs:
Simplocker: First Confirmed File-Encrypting Ransomware for Android
The dawn of ransomwear: How ransomware could move to wearable devices

Antivirus Protection Dates

  • Initial Rapid Release version 23 July 2014 revision 006
  • Latest Rapid Release version 15 January 2018 revision 020
  • Initial Daily Certified version 23 July 2014 revision 025
  • Latest Daily Certified version 15 January 2018 revision 024
  • Initial Weekly Certified release date 30 July 2014
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.
Android package file
The Trojan may arrive as a package with the following characteristics:

Package name:
Version: 1.0

When the Trojan is being installed, it requests permissions to perform the following actions:
  • Open network connections
  • Access information about networks
  • Check the phone's current state
  • Start once the device has finished booting
  • Prevent processor from sleeping or screen from dimming
  • Monitor incoming SMS messages
  • Write to and read from external storage devices
  • Access the camera
  • Access information about currently or recently running tasks

Once installed, the application will display an icon of a white lower case F on a red background above the text Video Player.

When the Trojan is executed, it displays a message claiming that the device has been locked as the user has been viewing illegal pornography.

The Trojan then scans the SD card (if one is available) on the compromised device for the following file types:
  • jpeg
  • jpg
  • png
  • bmp
  • gif
  • pdf
  • doc
  • docx
  • txt
  • avi
  • mkv
  • 3gp
  • mp4
  • zip
  • 7z
  • rar

If the Trojan finds any of these files, it encrypts them and attaches the following extension to the files:

It then gives instructions on how the user can pay a ransom fee to unlock the device and decrypt the files.

The Trojan may also connect to the following remote location:

The Trojan may also activate the device's camera and display an image of the user within the ransom note.


Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your device has been affected by this risk.

Install Norton Mobile Security
If you do not already have Norton Mobile Security installed on your device, please download the product from the Google Play Store .

Alternatively, you can navigate to the website from your device and download the product from there by completing the following steps:
  1. Select the 90-Day free download.
  2. Select the Android icon to begin downloading the product.
  3. Select Install in order to accept the permissions that are being requested by the program.
  4. Next, select Open and then Agree & Launch.

Note: The first time the product runs, you will be required to enter a code that is displayed on the screen in order to activate the product. Enter the provided code and select Submit .

Run a full system scan
Run a full system scan using Norton Mobile Security to remove this risk from the device. To do this, please perform the following actions:
  1. Navigate to the Anti-Malware tab.
  2. Select Scan Now.

Manual removal
To remove this risk manually, please perform the following actions:
  1. Open the Google Android Menu.
  2. Go to the Settings icon and select Applications.
  3. Next, select Manage.
  4. Select the application and select Uninstall.
Writeup By: Roberto Sponchioni