BackDoor.Butirat.91 is a backdoor that, before being installed on the system, checks HKCU(HKLM)\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Taskhost for the path to its executable file. If the path is similar to the current location, installation does not start.
The malicious program places its copy with the taskhost.exe name into %APPDATA% or with the taskhost.exe name into %SystemRoot% \System32. Then it adds the file path to the HKCU(HKLM)\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\Taskhost registry branch. The Trojan stores all data in the System.log file that resides in the same folder as the executable file.
BackDoor.Butirat.91 serves the purpose of stealing passwords stored by popular FTP clients (such as FlashFXP, Total Commander, Filezilla, FAR, WinSCP, FtpCommander, SmartFTP) and forwarding this data to cybercriminals. Moreover, the Trojan can download executable files from remote hosts and generate traffic for certain websites.
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.
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.
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.
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;