Infostealer.Coced240b

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Discovered: February 16, 2001
Updated: February 13, 2007 11:35:16 AM
Also Known As: Trojan.PWS.Coced.240.b [KAV], PWS.gen [McAfee], NAEBI.240B.Trojan, Troj/Coced-240 [Sophos], TROJ_COCED.240 [Trend], Win32.PSW.Coced.240.B [CA], PWSteal.Coced240b.Tro
Type: Trojan Horse
Systems Affected: Windows



The password stealer appears as an attachment named 26705-i386-update.exe. It claims to be a vulnernability patch that is mailed from support@microsoft.com. The Trojan sends confidential password information to an email address.

Microsoft has posted information regarding bogus files such as this at:

http://www.microsoft.com/technet/treeview/default.asp?url=/technet/security/news/patch_hoax.asp

Note: Definitions prior to May 10, 2006 may detect this threat as PWSteal.Coced240b.Tro.

Antivirus Protection Dates

  • Initial Rapid Release version February 20, 2001
  • Latest Rapid Release version August 20, 2008 revision 017
  • Initial Daily Certified version February 20, 2001
  • Latest Daily Certified version August 20, 2008 revision 016
  • Initial Weekly Certified release date February 20, 2001

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


Technical Description


This password-stealing Trojan comes as an attachment to an email message that appears to be from support@microsoft.com. The name of the attachment is 26705-i386-update.exe. The email message claims that this file is a vulnerability patch being distributed by Microsoft. This file is not an actual file from Microsoft.

When executed, the Trojan adds the value

mcidial

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

It also adds itself to the run= line in the Win.ini file.

Either of these will cause the Trojan to run when you start Windows.

Finally, in the System.ini file, the Trojan adds the line Explorer=Explorer <file name> where <file name> is the location of the Trojan on the infected system.

This Trojan does not mail itself to others; someone must send you the file.

Additional information for Windows 2000 users
In addition to the actions described previously, when the Trojan runs on Windows 2000, it makes the following changes to the registry:

  • To the key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    it adds the value:

    mcidial   C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
  • To the key:

    HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows

    it adds the value:

    run    C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
  • To the key:

    HKEY_CURRENT_USER\Software\Mirabilis\ICQ\Agent\Apps\Run

    it adds the value:

    path   C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
  • To the key:

    HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WOW\boot

    it adds the value:

    Explorer      Explorer C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe


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.


Removal


To remove this Trojan horse, run a full system scan and delete infected files, and then remove the changes that the Trojan made to the registry and to the Win.ini and System.ini files.

To scan for viruses:

  1. Run LiveUpdate to make sure that you have the most recent virus definitions.
  2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
  3. Delete any file detected as Infostealer.Coced240b.

To edit the registry:

CAUTION : We strongly recommend that you back up the system registry before making any changes. Incorrect changes to the registry could result in permanent data loss or corrupted files. Please make sure you modify only the keys specified. Please see the document How to back up the Windows registry before proceeding.
  1. Click Start, and click Run. The Run dialog box appears.
  2. Type regedit and then click OK. The Registry Editor opens.
  3. Navigate to the following subkey:

    HKEY_LOCAL_MACHINE\Software\Microsoft\
    Windows\CurrentVersion\Run
  4. In the right pane, delete the following value:

    mcidial
  5. Do one of the following:
    • If you are using Windows 95/98, skip to step 7.
    • If you are using Windows 2000, go on to step 6.
  6. Windows 2000 users must also remove the following registry values:
    • From the key:

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

      delete the value:

      mcidial   C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
    • From the key:

      HKEY_CURRENT_USER\Software\Microsoft\Windows NT\CurrentVersion\Windows

      delete the value:

      run    C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
    • From the key:

      HKEY_CURRENT_USER\Software\Mirabilis\ICQ\Agent\Apps\Run

      delete the value:

      path   C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
    • From the key:

      HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\WOW\boot

      delete the value:

      Explorer      Explorer C:\Documents and Settings\Administrator\My Documents\26705-i386-update.exe
  7. Click Registry, and click Exit to save the changes and close the Registry Editor.

To edit system files:
  1. Click Start, and click Run.
  2. Type sysedit and then click OK.
  3. Click the title bar of the Win.ini file.
  4. In the [windows] section, locate the run= line.
  5. Delete the text to the right of the equal (=) sign.
  6. Click the title bar of the of the System.ini file.
  7. In the [boot] section, locate and delete the following line:

    explorer=explorer <file name>
  8. Save your changes, and then restart the computer.


Writeup By: Brian Ewell