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You have been re-routed to the Ransom:Win32/Loktrom.A write up because Trojan%3aWin32%2fRansom.EZ has been renamed to Ransom:Win32/Loktrom.A
 

Ransom:Win32/Loktrom.A


This threat is a trojan that prevents you from accessing your desktop. It displays a message screen stating that you need to send payment to a certain prepaid mobile account to unlock the desktop.



What to do now

Microsoft doesn’t recommend you pay the fine. There is no guarantee that paying the ransom will give you access to your files.

If you've already paid, see our ransomware page for help on what to do now.

Run antivirus or antimalware software

The following free Microsoft software detects and removes this threat:

Even if we've already detected and removed this particular threat, running a full scan might find other malware that is hiding on your PC.

Advanced troubleshooting

To restore your PC, you might need to download and run Windows Defender Offline. See our advanced troubleshooting page for more help.

You can also ask for help from other PC users at the Microsoft virus and malware community.

If you’re using Windows XP, see our Windows XP end of support page.

Threat behavior

This threat is a trojan that prevents you from accessing your desktop. It displays a message screen stating that you need to send payment to a certain prepaid mobile account to unlock the desktop.

Installation

It may have a randomly-generated file name. It creates the following registry entries so that it automatically runs every time Windows starts:

In subkey: HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
Sets value: "Shell"
With data: "<malware file name>"

In subkey: HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Sets value: "explorer"
With data: "<malware file name>"

Payload

Prevents you from accessing the desktop

It locks your desktop, preventing you from accessing it. It displays a message screen stating that illegal activity has been detected in your computer and that you have to send payment to a given mobile phone account to regain access. The screen may appear similar to the following:

This trojan claims that upon sending payment, you will be sent an unlock code to regain access. It also falsely claims association with Windows and Microsoft Security Essentials, when in fact this trojan has nothing to do whatsoever with Windows or Microsoft.

Analysis by Stefan Sellmer


Symptoms

System changes

The following system changes may indicate the presence of this malware in your computer:

  • The display of the following image:

Prevention


Alert level: Severe
First detected by definition: 1.111.1889.0
Latest detected by definition: 1.175.888.0 and higher
First detected on: Sep 09, 2011
This entry was first published on: Sep 12, 2011
This entry was updated on: Jun 05, 2014

This threat is also detected as:
  • Trojan-Ransom.Win32.Gimemo.wrn (Kaspersky)
  • W32/Ransom.BIB (Norman)
  • TR/Ransom.EZ.361 (Avira)
  • Trojan-Ransom.Win32.Gimemo (Ikarus)
  • Troj/Ransom-HA (Sophos)