Dialer.Mostrar

Dialer.Mostrar

Updated:
February 13, 2007
Publisher:
Matrix Technology Network
Risk Impact:
High
File Names:
msa64chk.dll
Systems Affected:
Windows

Behavior


When Dialer.Mostrar is executed, it installs itself and attempts to use the modem to dial to a pay telephone number.

Symptoms


Your Symantec product detects this threat as Dialer.Mostrar.

Behavior


The most common installation method for this dialer program is through various Web sites.

Antivirus Protection Dates

  • Initial Rapid Release version October 02, 2014 revision 022
  • Latest Rapid Release version February 01, 2015 revision 020
  • Initial Daily Certified version December 07, 2004
  • Latest Daily Certified version September 28, 2010 revision 036
  • Initial Weekly Certified release date December 08, 2004
Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

When Dialer.Mostrar is executed, it does the following:
  1. Adds the value:

    "Dialer"="<value may vary>"

    to the registry key:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

    so that the dialer runs every time Windows starts.

  2. Creates the following registry keys:

    HKEY_CURRENT_USER\PTPSA32.PTPSAWeb
    HKEY_CURRENT_USER\PTPSA32.PTPSAWeb.1
    HKEY_CURRENT_USER\CLSID\{88C51E90-8E9C-4C96-8A45-574D88B63FAF}
    HKEY_CURRENT_USER\TypeLib\{095C0DB4-FEA6-440E-8DFC-00FC53AC827D}
    HKEY_CURRENT_USER\Interface\{5BF0CE3E-61D2-4A7B-BAA3-0C4667A9563D}
    HKEY_CURRENT_USER\Interface\{4FC63700-2093-4AD2-8D37-3B3D86D9C940}

  3. May modifiy the value:

    "Start Page"

    in the registry key:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Internet Explorer\Main

    which changes the home page of Internet Explorer.


The following instructions pertain to all Symantec antivirus products that support Security Risk detection.
  1. Update the definitions.
  2. Close modem connections
  3. Unregister the msa64chk.dll file.
  4. Run a full system scan.
  5. Delete the value that was added to the registry.
For specific details on each of these steps, read the following instructions.

1. To update the definitions
To obtain the most recent definitions, start your Symantec program and run LiveUpdate.

2. To close modem connections
This risk uses available modems to create an Internet connection, sometimes without any visible signs. In order to successfully remove this threat, ensure that all modem-based Internet connections are disconnected before proceeding. For instructions on how to do this, consult the appropriate Internet service provider, computer manufacturer, or operating system documentation.

3. To unregister the msa64chk.dll file
  1. Click Start > Run.
  2. Type, or copy and paste, the following text:

    regsvr32 /u "[path to file]\msa64chk.dll"

    where [path to file] represents the location of the file on the user's computer.

    then click OK.

  3. If a dialog box confirming this action appears, click OK.

4. To run the scan
  1. Start your Symantec antivirus program, and then run a full system scan.
  2. If any files are detected as Dialer.Mostrar and depending on which software version you are using, you may see one or more of the following options:

    Note: This applies only to versions of Norton AntiVirus that support Security Risk detection. If you are running a version of Symantec AntiVirus Corporate Edition that supports Security Risk detection, and Security Risk detection has been enabled, you will only see a message box that gives the results of the scan. If you have questions in this situation, contact your network administrator.
    • Exclude (Not recommended): If you click this button, it will set the threat so that it is no longer detectable. That is, the antivirus program will keep the security risk on your computer and will no longer detect it to remove from your computer.

    • Ignore or Skip: This option tells the scanner to ignore the threat for this scan only. It will be detected again the next time that you run a scan.

    • Cancel: This option is new to Norton Antivirus 2005. It is used when Norton Antivirus 2005 has determined that it cannot delete a security risk. This Cancel option tells the scanner to ignore the threat for this scan only, and thus, the threat will be detected again the next time that you run a scan.

      To actually delete the security risk:
      • Click its file name (under the Filename column).
      • In the Item Information box that displays, write down the full path and file name.
      • Then use Windows Explorer to locate and delete the file.

        If Windows reports that it cannot delete the file, this indicates that the file is in use. In this situation, complete the rest of the instructions on this page, restart the computer in Safe mode, and then delete the file using Windows Explorer.

    • Delete: This option will attempt to delete the detected files. In some cases, the scanner will not be able to do this.
      • If you see a message, "Delete Failed" (or similar message), manually delete the file.
      • Click the file name of the threat that is under the Filename column.
      • In the Item Information box that displays, write down the full path and file name.
      • Then use Windows Explorer to locate and delete the file.

        If Windows reports that it cannot delete the file, this indicates that the file is in use. In this situation, complete the rest of the instructions on this page, restart the computer in Safe mode, and then delete the file using Windows Explorer.

5. 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 keys only. Read the document, "How to make a backup of the Windows registry ," for instructions.


Note:
This is done to make sure that all the keys are removed. They may not be there if regsvr32 removed them.

  1. Click Start > Run.
  2. Type regedit

    Then click OK.

  3. Navigate to the key:

    HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

  4. In the right pane, delete the value:

    "Dialer"

  5. Exit the Registry Editor.