Printer Friendly Page

Discovered: September 16, 2013
Updated: September 17, 2013 10:32:24 AM
Type: Trojan
Systems Affected: Windows

Trojan.Ransomlock.AI is a Trojan horse that locks the desktop making the computer unusable. It then asks the user to pay to have it unlocked.

For more information, please see the following resource:

Antivirus Protection Dates

  • Initial Rapid Release version September 16, 2013 revision 007
  • Latest Rapid Release version September 16, 2013 revision 007
  • Initial Daily Certified version September 16, 2013 revision 022
  • Latest Daily Certified version September 16, 2013 revision 022
  • Initial Weekly Certified release date September 18, 2013

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Technical Description

The Trojan must be manually installed.

When the Trojan is executed, it creates the following file:

It then disables task switching and hides the taskbar.

Next, it creates the following registry entry so that it executes whenever Windows starts:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run\"blue" = "\"%CurrentFolder%\[ORIGINAL FILE NAME].exe\""

The Trojan then creates the following registry entry to disable Task Manager:
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System\"DisableTaskMgr" = "1"

The Trojan then hides the desktop and shows a fake blue screen asking the user to contact a specified QQ number to purchase a password.

Next, the Trojan asks the user to press the F10 key in order to enter the password and unlock the computer. All other keys may be disabled until the F10 key is pressed.

Computers compromised with Trojan.Ransomlock.AI can be unlocked using the following passwords:

Sample MD5: 4b6cbe978ab249a06a8ff5e5d9a0b778
Password: 4049133195201314

Sample MD5: 6c0039f4e354d78fb9fed032b9d95c62
Password: 5438

Sample MD5: 7272842f13f40a2d05669daae6b7732b
Password: 54sb+2b=hp

Sample MD5: 91a37b30dce6e41b96adaf30a939a500
Password: 610938

Sample MD5: b35361a2087268347c18b111ed749c00
Password: woshidashabi

Sample MD5: d61cf1670fd0ef41bf34cb4cc3ce5bff
Password: taizizhizuo

Sample MD5: e3baaec8269de4af3cd1f5746b9249e5
Password: feifei520

Sample MD5: f45199bfaaebe21528efaa7bc35c925e
Password: 895219272


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 computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.

If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool

If you have an infected Windows system file, you may need to replace it using the Windows installation CD .

How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.

If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.

Removal Tool

If you have an infected Windows system file, you may need to replace it using the Windows installation CD .

How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network

The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product

2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.

Writeup By: Liang Yuan