Nasty troyan!

[canada]

Hello everyone! It's been quite a while since my last post here. Anyway, I got this problem here. Some time ago I was infected by a troyan. I knew it because my firewall showed a strange connection. A program (winsock.exe) tries to connect to a certain adress. I cleaned all the links to this program in the registry(never had it before) and deleted it itself and blocked it with firewall. But it kept coming back. On windows startup it runs some 'kernel1' and afterwards 'kernel_1' and that brings all the things back to the way they were. Although if I sit on 'ctrl+alt+del' during a windows loadup I can just close those processes, but that is kinda exausting, I got tired of that. I know my computer like myself also the registry-I cleaned it up, but it keeps coming back. Perhaps it wrote itself in rundll32? Does anyone have any ideas on how to trace the way this sucker installs himself all over again?

[KorpDeath]

Run a trojan scanner like Tauscan on your machine. www.agnitum.com

As for finding out how it installs itself, after you figure out which one it is, just go look it up on that site or pretty much any other anti-virus vendor should have the info.

Good luck.

[xmaddness]

Well I did a quick Google and I found this

Backdoor.Death
Discovered on: August 18, 2001
Last Updated on: April 15, 2002 at 04:47:26 PM PDT


Backdoor.Death is a typical Backdoor Trojan, which gives a remote attacker unobstructed access to your computer.


Also Known As: Backdoor.Death.25, Backdoor.Death.26
Type: Trojan Horse
Infection Length: multiple files




Wild:

Number of infections: 0 - 49
Number of sites: 0 - 2
Geographical distribution: Low
Threat containment: Easy
Removal: Easy
Threat Metrics


Wild:
Low
Damage:
Medium
Distribution:
Low






The backdoor Trojans in this family typically add keys or values to these registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\sockets

They may also add load and run lines to the following system files:

C:\Windows\win.ini
C:\Windows\system.ini

Version 26
Backdoor.Death (v26) does the following:

Registry changes


It adds the value

winfont.exe C:\Windows\FONTS\winfont.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

It adds the value

internat.exe internat.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

It adds the value

winfont.exe C:\Windows\FONTS\winfont.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce


It creates the registry key

\sockets

under the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion

It also creates an entire subkey structure under the \sockets subkey.

System file changes
It modifies the following system files:

C:\Windows\Win.ini. It adds the following lines:

load=C:\Windows\FONTS\winfont.exe
run=C:\Windows\FONTS\winfont.exe
C:\Windows\System.ini. It adds the line:

load=C:\Windows\FONTS\winfont.exe

Dropped files
This Trojan creates the following files on your system:
C:\Windows\FONTS\Winfont.exe
C:\Windows\System\Internat.exe (the original is saved as C:\Windows\Interface.dll, Kernel1.exe, Kernel_1.exe, Kernel2.exe, or Kernel_2.exe in the Windows \Temp folder.
C:\Windows\System\Runexec.dll
C:\Autorun.inf
C:\Windows\Avp32.ini
C:\Windows\Avpm.ini

Version 25
Backdoor.Death (v25) does the following:

Registry changes

It adds the value

internat.exe internat.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

It adds the value

winupdate.exe C:\Windows\FONTS\winupdate.exe

to the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce


It creates the registry key

\socket

under the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft

It also creates an entire subkey structure under the \socket subkey.

System file changes
It modifies the following system files:

C:\Windows\Win.ini. It adds the following lines:

load=C:\Windows\FONTS\winupdate.exe
run=C:\Windows\FONTS\winupdate.exe
C:\Windows\System.ini. It adds the line:

load=C:\Windows\FONTS\winupdate.exe

Dropped files
This Trojan creates the following files on your system:
C:\Windows\FONTS\Winupdate.exe
C:\Windows\System\Internat.exe (the original is saved as C:\Windows\Interface.dll, Kernel1.exe, Kernel_1.exe, Kernel2.exe, or Kernel_2.exe in the C:\Windows\Temp folder.
C:\Windows\System\Runexec.dll
C:\Autorun.inf
C:\Windows\Avp32.ini
C:\Windows\Avpm.ini




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, a telnet server, 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.
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.


To remove this Trojan, delete files detected as Backdoor.Death and reverse the changes that it made to the registry and to system files.

To remove the Trojan files:
1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
3. Run a full system scan.
4. If NAV detects any files as Backdoor.Death, first write down the name and location of the infected file, and then choose to delete it. (You will need this information in the sections that follow.)

NOTE: As an alternative to writing down the file names, you can print a copy of the Norton AntiVirus Activity log. The log contains information on what was detected, the location of the file, and what was done to it. To do this:
1. With NAV still open, click Reports.
2. Double-click "View the log of Norton AntiVirus activities."
3. Click Print.

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 and select the following key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

4. Refer to the list of infected files that you created while following the instructions in the previous section. In the right pane, look at the entries in the Name and Data columns.
5. If you find an entry that refers to a file that was detected as infected, select the entry, press Delete, and then click Yes to confirm.
6. Repeat steps 3 to 5 for the following registry keys:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServicesOnce

7. Navigate to and select the following key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Sockets

8. Select the \Sockets subkey and delete it.
9. Exit the Registry Editor.

Edit Windows startup files

NOTES:
The instructions in this section applies only to Windows 95/98/Me. It is not necessary to do this if you are running Windows NT/2000.
(For Windows Me users only) Due to the file-protection process in Windows Me, there is a backup copy of the file that you are about to edit in the C:\Windows\Recent folder. We recommend that you delete this file before you continue with the steps in this section. To do so using Windows Explorer, go to the C:\Windows\Recent folder, and in the right pane delete the Win.ini file. It will be regenerated as a copy of the file that you are about to edit when you save your changes to that file.
1. Click Start, and click Run.
2. Type the following, and then click OK.

edit c:\windows\win.ini

The MS-DOS Editor opens.

NOTE: If Windows is installed in a different location, make the appropriate path substitution.

CAUTION: The steps that follow instruct you to remove text from the load= and run= lines of the Win.ini file. If you are using older programs, they may be loading at startup from one of these lines. Make sure that you remove only the lines shown.

3. Locate the load= and run= lines within the [windows] section of the Win.ini file; this section is usually located near the top of the file.
4. See if these lines look like the following:

load=C:\Windows\FONTS\winfont.exe
run=C:\Windows\FONTS\winfont.exe

5. If they do, for each line do the following:
a. Position the cursor immediately to the right of the equal (=) sign.
b. Press Shift+End to select all of the text to the right of the equal sign, and then press Delete.
6. Click File, click Exit, and then click Yes when you are prompted to save the changes.
7. Click Start, and click Run.
8. Type the following, and then click OK.

edit c:\windows\system.ini

The MS-DOS Editor opens.

NOTE: If Windows is installed in a different location, make the appropriate substitution.

9. Locate the line

load=C:\Windows\FONTS\winfont.exe

within the [boot] section of the System.ini file; the section is usually located near the top of the file.

10. Select and then delete this line.
11. Click File, click Exit, and then click Yes when you are prompted to save the changes.

This completes the removal part of the process. Even though you did so previously, start NAV and run another full system scan. Delete any files that were found to be infected with Backdoor.Death. When you have finished, restart the computer.

Hope that helped.

[Scorp666]

Is it that much more work to format you HD and install your OS?

Most of the time I find troubleshooting sucker punches like that takes much more time then formatting and starting from scratch!

And at the same time, you have a clean system without all the junk you might have downloaded in the past months...

[canada]

Thanx a lot for help. I cleaned it in win.ini and system.ini also, plus I used Troyan Remover, but this is a nasty sucker! As for the favorite 'format c:' - nah! It takes me a couple of days to bring the system to the way it was before(install all soft etc), add extreme laziness to that...