Discovered: July 15, 2005
Updated: February 13, 2007 12:42:19 PM
Also Known As: Lebreat [F-Secure], Net-Worm.Win32.Lebreat.gen [Ka, W32/Reatle.gen@MM [McAfee], W32/Lebreat.C.worm [Panda], W32/Lebreat-C [Sophos], WORM_REATLE.C [Trend Micro]
Type: Worm
Systems Affected: Windows



W32.Reatle.C@mm is a variant of W32.Reatle@mm , and is a mass-mailing worm that opens a back door and attempts to spread by exploiting the Microsoft Windows LSASS Buffer Overrun Vulnerability (Microsoft Security Bulletin MS04-011 ) on TCP port 445.

It also downloads a copy W32.Rants.B@mm and a variant of W32.Spybot.Worm .

Antivirus Protection Dates

  • Initial Rapid Release version July 16, 2005
  • Latest Rapid Release version November 15, 2017 revision 016
  • Initial Daily Certified version July 16, 2005
  • Latest Daily Certified version November 15, 2017 revision 009
  • Initial Weekly Certified release date July 20, 2005

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

Writeup By: Maryl Magee

Discovered: July 15, 2005
Updated: February 13, 2007 12:42:19 PM
Also Known As: Lebreat [F-Secure], Net-Worm.Win32.Lebreat.gen [Ka, W32/Reatle.gen@MM [McAfee], W32/Lebreat.C.worm [Panda], W32/Lebreat-C [Sophos], WORM_REATLE.C [Trend Micro]
Type: Worm
Systems Affected: Windows


When W32.Reatle.C@mm is executed, it performs the following actions:

  1. Copies itself as the following:

    • %System%\ccapp.exe
    • %System%\Windows.exe
    • %System%\attach.tmp
    • %Windir%\bxt.com
    • %Windir%\update3.exe

      Note:
    • %System% is a variable that refers to the System folder. By default this is C:\Windows\System (Windows 95/98/Me), C:\Winnt\System32 (Windows NT/2000), or C:\Windows\System32 (Windows XP).
    • %Windir% is a variable that refers to the Windows installation folder. By default, this is C:\Windows (Windows 95/98/Me/XP) or C:\Winnt (Windows NT/2000).

  2. Adds the value:

    "WIN"= "C:\WINNT\System32\windows.exe"

    to the registry subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows

    so that the risk runs every time Windows starts.

  3. Downloads and executes the following files:

  4. Modifies the value:

    "EnableFirewall" = "1"

    in the registry subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\
    DomainProfile
    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\
    StandardProfile

    to disable the firewall.

  5. Modifies the value:

    "NoAutoUpdate" = "1"

    in the registry subkeys:

    HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\
    WindowsUpdate\AU
    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\
    WindowsUpdate\AU

    to disable automatic Windows Updates.

  6. Modifies the values:

    "AntiVirusDisableNotify" = "0"
    "UpdatesDisableNotify" = "0"
    "FirewallDisableNotify" = "0"

    in the registry subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Security Center
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center

    to disable notification of firewall, antivirus and update status through the Windows Security Center.

  7. Modifies the value:

    "DisableSR" = "1"

    in the registry subkeys:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore

    to disable System Restore.

  8. Modifies the values:

    "DisableTaskMgr" = "1"
    "DisableRegistryTools" = "1"

    in the registry subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\System
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
    Policies\System

    to disable the Task Manager and the Registry Editor.

  9. Gathers email addresses from files with the following extensions:

    • .asp
    • .txt
    • .adb
    • .tbb
    • .dbx
    • .html
    • .htm
    • .wab

  10. Saves the gathered email addresses in the file %Windir%\xzy6.tmp.

  11. Avoids sending itself to email addresses that contain any of the following strings:

    • icrosof
    • .gov
    • panda
    • f-secur
    • icrosoft
    • winrar
    • winzip
    • @mcafee
    • @trendmicro
    • @mm
    • @noreply
    • @sopho
    • @norman
    • @virusli
    • @norton
    • @fsecure
    • @panda
    • @avp
    • @microsoft
    • @symantec

  12. Uses its own SMTP engine to send itself to the gathered email addresses. The email has the following characteristics:

    From:
    One of the following:

    • adam
    • admin
    • alerts
    • alex
    • bob
    • brenda
    • brent
    • dan
    • david
    • fred
    • helen
    • jack
    • jane
    • jerry
    • joe
    • john
    • jon
    • josh
    • leo
    • linda
    • mary
    • matt
    • michael
    • mike
    • paul
    • ray
    • robert
    • root
    • sales
    • steve
    • support
    • ted
    • tom

      with one of the following domains:

    • @nai.com
    • @gmail.com
    • @trendmicro.com
    • @support.com
    • @matrix.com
    • @aol.com
    • @ca.com
    • @mcafee.com
    • @arcor.com
    • @antivirus.com
    • @google.com
    • @hotmail.com
    • @yahoo.com
    • @microsoft.com
    • @msn.com
    • @symantec.com


      Subject:
      One of the following:

    • Message could not be delivered
    • Bug
    • Error
    • Email
    • Mail Delivery System
    • Importnat Information
    • **WARNING** Your Account Currently Disabled.
    • Password
    • info
    • Hello


      Message:
      One of the following:

    • Your credit card was charged for $500 USD. For additional information see the attachment.
    • Binary message is available.
    • The message contains Unicode characters and has been sent as a binary attachment.
    • Here are your banks documents
    • The original message was included as an attachment.
    • We have temporarily suspended your email account checkout the attachment for more info.
    • You have successfully updated the password of your domain account checkout the attachment for more info.
    • Important Notification checkout the attachment for more info.
    • Your Account Suspended checkout the document.
    • Your password has been updated checkout the document.
      checkout the attachment.
    • Hello,
      I was in a hurry and I forgot to attach an important
      document. Please see attached.


      Attachment:
      One of the following:

    • payment.doc [SPACES] .scr
    • about.doc [SPACES] .bat
    • help.doc [SPACES] .exe
    • account-report.exe
    • about.cpl
    • about.scr
    • admin.bat
    • archive.cpl
    • archive.exe
    • box.bat
    • box.scr
    • data.bat
    • data.scr
    • doc.pif
    • docs.cpl
    • docs.scr
    • document.cpl
    • document.exe
    • file.cpl
    • inbox.cpl
    • inbox.exe
    • order.cpl
    • order.exe
    • read.cpl
    • read.exe
    • readme.cpl
    • readme.scr

  13. Opens an FTP server on TCP port 8885.

  14. Attempts to connect to a random range of IP addresses on TCP port 445 by using the Microsoft Windows LSASS Buffer Overrun Vulnerability (as described in Microsoft Security Bulletin MS04-011).

    Note: If a successful connection is made, the worm will be downloaded onto the newly compromised computer.

  15. Attempts to perform a denial of service attack against www.symantec.com by targeting port 1052 with randomly generated packets.

    Note: Port 1052 corresponds to the dynamic DNS service.


Recommendations

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.

Writeup By: Maryl Magee

Discovered: July 15, 2005
Updated: February 13, 2007 12:42:19 PM
Also Known As: Lebreat [F-Secure], Net-Worm.Win32.Lebreat.gen [Ka, W32/Reatle.gen@MM [McAfee], W32/Lebreat.C.worm [Panda], W32/Lebreat-C [Sophos], WORM_REATLE.C [Trend Micro]
Type: Worm
Systems Affected: Windows


Removal using the W32.Reatle@mm Removal Tool
Symantec Security Response has developed a removal tool to clean the infections of W32.Reatle.C@mm. Use this removal tool first, as it is the easiest way to remove this threat.

Manual Removal:

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

  1. Disable System Restore (Windows Me/XP).
  2. Update the virus definitions.
  3. Run a full system scan and delete all the files detected.
  4. Delete any values added to the registry.
  5. Restore the Windows Security Center.
For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:
Note:
When you are completely finished with the removal procedure and are satisfied that the threat has been removed, reenable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article: Antivirus Tools Cannot Clean Infected Files in the _Restore Folder (Article ID: Q263455).

2. To update the virus definitions
Symantec Security Response fully tests all the virus definitions for quality assurance before they are posted to our servers. There are two ways to obtain the most recent virus definitions:
  • Running LiveUpdate, which is the easiest way to obtain virus definitions: These virus definitions are posted to the LiveUpdate servers once each week (usually on Wednesdays), unless there is a major virus outbreak. To determine whether definitions for this threat are available by LiveUpdate, refer to Virus Definitions (LiveUpdate).
  • Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. You should download the definitions from the Symantec Security Response Web site and manually install them. To determine whether definitions for this threat are available by the Intelligent Updater, refer to Virus Definitions (Intelligent Updater).

    The latest Intelligent Updater virus definitions can be obtained here: Intelligent Updater virus definitions. For detailed instructions read the document: How to update virus definition files using the Intelligent Updater.


3. To scan for and delete the infected files
  1. Start your Symantec antivirus program and make sure that it is configured to scan all the files.
  2. Run a full system scan.
  3. If any files are detected, click Delete.
  4. Delete the %Windir%\xzy6.tmp file, if it is not needed. If you are unsure about this, you can leave this file without causing any further harm to the computer.

Important: If you are unable to start your Symantec antivirus product or the product reports that it cannot delete a detected file, you may need to stop the risk from running in order to remove it. To do this, run the scan in Safe mode. For instructions, read the document, How to start the computer in Safe Mode . Once you have restarted in Safe mode, run the scan again.

After the files are deleted, restart the computer in Normal mode and proceed with the next section.

Warning messages may be displayed when the computer is restarted, since the threat may not be fully removed at this point. You can ignore these messages and click OK. These messages will not appear when the computer is restarted after the removal instructions have been fully completed. The messages displayed may be similar to the following:

Title: [FILE PATH]
Message body: Windows cannot find [FILE NAME]. Make sure you typed the name correctly, and then try again. To search for a file, click the Start button, and then click Search.


4. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. For instructions refer to the document: How to make a backup of the Windows registry.
  1. Click Start > Run.
  2. Type regedit
  3. Click OK.

    Note: If the registry editor fails to open the threat may have modified the registry to prevent access to the registry editor. Security Response has developed a tool to resolve this problem. Download and run this tool, and then continue with the removal.

  4. Navigate to the subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Windows

  5. In the right pane, delete the value:

    "WIN"= "C:\WINNT\System32\windows.exe"

  6. Navigate to the subkeys:

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\
    DomainProfile
    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall\
    StandardProfile

  7. In the right pane, reset the value to the original value if applicapble:

    "EnableFirewall" = "1"

  8. Navigate to the subkeys:

    HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\
    WindowsUpdate\AU
    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\
    WindowsUpdate\AU

  9. In the right pane, reset the value to the original value if applicapble:

    "NoAutoUpdate" = "1"

  10. Navigate to the subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Security Center
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Security Center

  11. In the right pane, reset the values to the original values if applicapble:

    "AntiVirusDisableNotify" = "0"
    "UpdatesDisableNotify" = "0"
    "FirewallDisableNotify" = "0"

  12. Navigate to the subkeys:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SystemRestore

  13. In the right pane, reset the value to the original value if applicapble:

    "DisableSR" = "1"

  14. Navigate to the subkeys:

    HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
    Policies\System
    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
    Policies\System

  15. In the right pane, reset the values to the original values if applicapble:

    "DisableTaskMgr" = "1"
    "DisableRegistryTools" = "1"

  16. Exit the Registry Editor.

5. To restore the Windows Security Center
This risk attempts to disable the features in the Windows Security Center, available in Windows XP Service Pack 2. If you are running Windows XP Service Pack 2 and would like to restore the full functionality of the Windows Security Center, please complete the following steps:

Important: If your computer is connected to a domain, you may not be able to adjust these settings. If so, contact your network administrator for more information.
  1. Click Start > Control Panel.
  2. Double-click the Security Center.
  3. In the right pane, click Windows Firewall. The Windows Firewall appears.
  4. Select On.
  5. Click OK to close the Windows Firewall.
  6. In the left pane of the Security Center, select Change the way Security Center alerts me.
  7. Click Alert Settings.
  8. Select Alert Settings, Firewall, and Virus Protection.
  9. Click OK
  10. Click Automatic Updates.
  11. Select Automatic.
  12. Click OK.
  13. Exit the Security Center.


Writeup By: Maryl Magee