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Trojan.Encoder.25129

Added to Dr.Web virus database:2018-04-16
Virus description was added:2018-04-17

SHA1:

  • de74dd60ba3448b072f03ad80001f6a903f60b60

An encryption Trojan that infects devices run by Microsoft Windows. The preventive protection of Dr.Web Anti-virus detects it as DPH:Trojan.Encoder.9.

Once launched, the Trojan checks the user’s location based on the IP address using the 2ip.ru service. Cybercriminals designed the malicious program so that it is not supposed to encrypt files if the device is located in Russia, Belarus and Kazakhstan, or the CultureInfo object that provides information on language and regional parameters has a Russian locale identifier. However, the encoder encrypts all files regardless of the IP address’s geographical location due to the code error.

The Trojan installs itself to the autorun using Windows Task Manager and encrypts the content of the following folders:

Trojan.Encoder.25129 screen #drweb

It encrypts files using the AES-256-CBC algorithms with the same key that is stored in the Trojan’s body. It adds the “.tron” extension to the encrypted files.

Files that exceed 30,000,000 bytes (about 28.6 MB) are not encrypted. Once the encryption is over, the “123” value is written into the %ProgramData%\\trig file. The Trojan then sends a request to the iplogger website. The website address is hardcoded into the program’s body. The malicious program then displays a window with ransom demands.

Trojan.Encoder.25129 screen #drweb

Once the HOW TO BUY BITCOIN button is clicked, the Trojan displays a window with instructions on how to buy the Bitcoin cryptocurrency:

Trojan.Encoder.25129 screen #drweb

The size of the ransom that cybercriminals demand differs from 0.007305 to 0.04 Btc.

In most cases, decrypting files corrupted by the encoder is impossible due to the code error.

Curing recommendations

  1. If the operating system (OS) can be loaded (either normally or in safe mode), download Dr.Web Security Space and run a full scan of your computer and removable media you use. More about Dr.Web Security Space.
  2. If you cannot boot the OS, change the BIOS settings to boot your system from a CD or USB drive. Download the image of the emergency system repair disk Dr.Web® LiveDisk , mount it on a USB drive or burn it to a CD/DVD. After booting up with this media, run a full scan and cure all the detected threats.
  3. If your OS is locked by malware belonging to the Trojan.Winlock family, use our unlocking service. If you failed to find the unlock code, follow the instructions provided in Section 2.
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  1. If the mobile device is operating normally, download and install Dr.Web for Android. Run a full system scan and follow recommendations to neutralize the detected threats.
  2. If the mobile device has been locked by Android.Locker ransomware (the message on the screen tells you that you have broken some law or demands a set ransom amount; or you will see some other announcement that prevents you from using the handheld normally), do the following:
    • Load your smartphone or tablet in the safe mode (depending on the operating system version and specifications of the particular mobile device involved, this procedure can be performed in various ways; seek clarification from the user guide that was shipped with the device, or contact its manufacturer);
    • Once you have activated safe mode, install the Dr.Web for Android onto the infected handheld and run a full scan of the system; follow the steps recommended for neutralizing the threats that have been detected;
    • Switch off your device and turn it on as normal.

Find out more about Dr.Web for Android

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Doctor Web is the Russian developer of Dr.Web anti-virus software. Dr.Web anti-virus software has been developed since 1992.

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