Backdoor.Cigivip

[Randy_Bell]

Symantec Security Response - Backdoor.Cigivip

Backdoor.Cigivip is a backdoor Trojan that gives an attacker unauthorized access to an infected computer. The Trojan also attempts to send login information for various instant messaging programs to the hacker. The existence of the file WinSys32.exe is a sign of a possible infection.

Also Known As: Backdoor.Cigivip.10 [AVP], New BackDoor2 [McAfee]
Type: Trojan Horse
Infection Length: 658,946 bytes
Systems Affected: Windows 95, Windows 98, Windows Millenium
Systems Not Affected: Windows NT, Windows 2000, Windows XP, Windows 3.x, Microsoft IIS, Macintosh, Unix, Linux

technical details

When Backdoor.Cigivip runs, it performs the following actions:

It copies itself as C:\Windows\WinSys32.exe.

It creates the value

WinSys32 C:\Windows\Winsys32.exe

in the registry key

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

so that the Trojan starts when you start or restart Windows.

The Trojan modifies the Win.ini file by adding the line

run=C:\Windows\Winsys32.exe

so that (on Windows 95/98/Millenium-based computers) the Trojan starts when you start or restart Windows.

The Trojan contains functionality that permits it to retrieve connection information (logon name and password) for these programs:

MSN Messenger
Mirabilis ICQ
AOL Instant Messenger

The retrieved information is then emailed to the hacker.

removal instructions

NOTE: These instructions are for all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Update the virus definitions.
2. Run a full system scan, and delete all files that are detected as Backdoor.Cigivip.
3. Delete the value

WinSys32 C:\Windows\Winsys32.exe

from the registry key

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

4. (Windows 95/98/Millenium only) Edit the Win.ini file to delete the text

C:\Windows\Winsys32.exe

from the run= line.

[/b]To delete the value from the registry:[/b]

CAUTION: Symantec strongly recommends that you back up the registry before you make any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify only the keys that are specified. Read the document How to make a backup of the Windows registry for instructions.

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 key

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run

4. In the right pane, delete the value

WinSys32 C:\Windows\Winsys32.exe

5. Exit the Registry Editor

To edit the Win.ini file:

This is necessary only on Windows 95/98/Millenium-based computers.

NOTE: (For Windows Millenium users only) Due to the file-protection process in Windows Millenium, a backup copy of the file that you are about to edit exists in the C:\Windows\Recent folder. Symantec recommends that you delete this file before you continue with the steps in this section. To do this using Windows Explorer, go to C:\Windows\Recent, and in the right pane select the Win.ini file and delete it. 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.

3. In the [windows] section of the file, look for an entry similar to the following:

run=C:\Windows\Winsys32.exe

4. Select the text to the right of the equal (=) sign. Be sure that you have not selected any other text, and then press Delete. When you are done, the line should look like this:

run=

5. Click File, and click Save.
6. Click File, and click Exit.