Infostealer.Coced240b

SUMMARY

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.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 20, 2001
• Virus Definitions (Intelligent Updater) February 20, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Low
• Releases Confidential Info: Steals password information.

Distribution

• Distribution Level: Low
• Name of Attachment: 26705-i386-update.exe
• Size of Attachment: 14,104 bytes

TECHNICAL DETAILS

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_MACHINESoftwareMicrosoftWindowsCurrentVersionRun

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_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
  
  it adds the value:
  
  mcidial   C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
  
• To the key:
  
  HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
  
  it adds the value:
  
  run    C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
  
• To the key:
  
  HKEY_CURRENT_USERSoftwareMirabilisICQAgentAppsRun
  
  it adds the value:
  
  path   C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
  
• To the key:
  
  HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWOWoot
  
  it adds the value:
  
  Explorer      Explorer C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

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_MACHINESoftwareMicrosoft
   WindowsCurrentVersionRun
   
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_MACHINESOFTWAREMicrosoftWindowsCurrentVersionRun
     
     delete the value:
     
     mcidial   C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
     
   • From the key:
     
     HKEY_CURRENT_USERSoftwareMicrosoftWindows NTCurrentVersionWindows
     
     delete the value:
     
     run    C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
     
   • From the key:
     
     HKEY_CURRENT_USERSoftwareMirabilisICQAgentAppsRun
     
     delete the value:
     
     path   C:Documents and SettingsAdministratorMy Documents26705-i386-update.exe
     
   • From the key:
     
     HKEY_LOCAL_MACHINESOFTWAREMicrosoftWindows NTCurrentVersionWOWoot
     
     delete the value:
     
     Explorer      Explorer C:Documents and SettingsAdministratorMy Documents26705-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.