Falta el archivo system32\ntoskrnl.exe

[Toté]

Hola! espero que me ayudeis a eliminar el virus que creo que tengo en mi Pc.



El Pc va lentísimo, no me deja actualizar Windows Update, desactiva la protección del antivirus y a veces al encenderlo sale el mensaje: "No se ha iniciado Windows porque falta el archivo system32\ntoskrnl.exe" aunque al pulsar intro sí se carga el Windows.



Muchas gracias!!

[msc hotline sat]

Posiblemente sea por el virus Gruel:





http://www.symantec.com/security_response/writeup.jsp?docid=2003-071316-1355-99&tabid=2




[quote]
W32.Gruel@mmRisk Level 2: LowPrinter Friendly Page

SUMMARY TECHNICAL DETAILS REMOVAL Discovered: July 13, 2003

Updated: November 18, 2003 02:22:35 PM ZE9

Also Known As: W32/Gruel-A [Sophos], W32/Fakerr@MM [McAfee], Win32.Gruel [CA]

Type: Worm

Infection Length: 102,400 bytes

Systems Affected: Windows 95, Windows 98, Windows NT, Windows 2000, Windows XP, Windows Me



When W32.Gruel@mm is run, it performs the following actions:



Deletes, or attempts to delete, the following files:

C:\Autoexec.bat

C:\Config.sys

C:\WINNT\System32\*.dll

C:\WINNT\System32\Ntoskrnl.exe

C:\WINNT\System32\Command.com

C:\WINNT\Regedit.exe

C:\Windows\System32\Ntoskrnl.exe

C:\Windows\System32\Command.com

C:\Windows\Regedit.exe

C:\WINNT\System32\*.exe

C:\WINNT\System32\*.com

C:\WINNT\System32\*.ocx

C:\Windows\System32\*.dll

C:\Windows\System32\*.ocx

C:\Windows\System32\*.exe

C:\Windows\System32\*.com





Copies itself as the Hidden system file, C:\Rundll32.exe.





Copies itself to C:\windows\Program Files\Kazaa\My Shared Folder\Windows XP KeyGen 2.5.exe.





Changes the Value data of the (Default) value to:



<filename of worm> %1



the following registry keys and values:



HKEY_CLASSES_ROOT\exefile\shell\open\command



HKEY_CLASSES_ROOT\comfile\shell\open\command



HKEY_CLASSES_ROOT\batfile\shell\open\command



HKEY_CLASSES_ROOT\piffile\shell\open\command



HKEY_CLASSES_ROOT\htafile\shell\open\command



HKEY_CLASSES_ROOT\htfile\shell\open\command



As a result of these changes, the worm runs every time one of the aforementioned program types is executed.





Sets the following registry keys and values:



HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

"MediaPath"="C:\Proyecto1.exe"



HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce

"Rundll32.exe"="C:\Rundll32.exe"



HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnceEX

"DevicePath" ="C:\Proyecto1.exe"



HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\SETUP

"NetCache"="C:\Proyecto1.exe"



HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion

"ProxyDevice"="C:\Proyecto1.exe"



HKEY_CURRENT_USER\Software\kIlLeRgUaTe 1.03





Displays a false message that Windows has found an error and asks you to submit the error to Microsoft. There are two buttons displayed in this "warning" message, "Send Error" and "Send and Close."

If you click "Send Error," a fake error log is displayed.

If you try to cancel the message, the message is repeatedly displayed. Clicking "Back" returns you to the original "warning" message.

If you click "Send and Close" the following actions occur:

Multiple Control Panel windows open.

The CD-ROM drive opens

A message from the author of this threat is displayed, and this message cannot be moved or closed.

The System Tray is disabled.

The Task Bar disappears.

Drive C is no longer visible and all the icons disappear.

Only open windows remain. The message windows, which the worm generates, obscure them.





Attempts to mail itself to all the addresses in the Microsoft Outlook Address book.

The email is formatted as follows:



Subject: Microsoft Windows Critical Update.



Message body:

Critical Update: The Microsoft Windows updates found on this patch include fixes to following Windows operating systems: Any update that is critical to the operation of your computer is considered a Critical Update, and is automatically selected for installation during the scan for available updates. This patch is provided to help resolve known issues, and to protect your computer from known security vulnerabilities and all kinds of viruses. Whether a patch applies to your operating system, software programs, or hardware, it is listed in the Critical Updates category, like this patch attached. For Support please contact us at support@microsoft.com.



Attachment: Windows Critical Update 088562.exe

or

Attachment: AntiVirus_Patch.exe



or



Subject: Symantec: New serious virus found



Message body:

Norton Security Response: has detected a new virus in the Internet. For this reason we made this tool attachement, to protect your computer from this serious virus. Due to the number of submissions received from customers, Symantec Security Response has upgraded this threat to a Category 5 (Maximum )



Attachment: Symantec_Norton_Tool.exe







RecommendationsSymantec 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.



Writeup By: Maryl Magee
[/quote]