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Trojan.Vundo Removal Tool
| Discovered on:
November 20, 2004 |
| Last Updated on:
November 25, 2004 11:01:52 AM
PST | |
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This tool is designed to remove the infections of
Trojan.Vundo.
Important:
- If you are on a network or have a full-time
connection to the Internet, such as a DSL or cable
modem, disconnect the computer from the network and
Internet. Disable or password-protect file sharing, or
set the shared files to Read Only, before reconnecting
the computers to the network or to the Internet.
Because this worm spreads by using shared folders on
networked computers, to ensure that the worm does not
re-infect the computer after it has been removed,
Symantec suggests sharing with Read Only access or by
using password protection.
For instructions on
how to do this, refer to your Windows documentation,
or the document, "How to configure shared Windows folders
for maximum network protection."
- If you are removing an infection from a network,
first make sure that all the shares are disabled or
set to Read Only.
- This tool is not designed to run on Novell NetWare
servers. To remove this threat from a NetWare server,
first make sure that you have the current virus
definitions, and then run a full system scan with the
Symantec antivirus product.
How to
download and run the tool
Important: You must have
administrative rights to run this tool on Windows NT
4.0, Windows 2000, or Windows XP.
Note for
network administrators: If you are running MS
Exchange 2000 Server, we recommend that you exclude the
M drive from the scan by running the tool from a command
line, with the Exclude switch. For more information,
read the Microsoft knowledge base article, "XADM:
Do Not Back Up or Scan Exchange 2000 Drive M"
(Article 298924).
Follow these steps to download
and run the tool:
- Download the FixVundo.exe file from: http://securityresponse.symantec.com/avcenter/FixVundo.exe
- Save the file to a convenient location, such as
your Windows desktop.
- Optional: To check the authenticity of the digital
signature, refer to the "Digital signature" section
later in this writeup.
Note: If you are
sure that you are downloading this tool from the
Security Response Web site, you can skip this step. If
you are not sure, or are a network administrator and
need to authenticate the files before deployment,
follow the steps in the "Digital signature" section
before proceeding with step 4.
- Close all the running programs.
- If you are on a network or if you have a full-time
connection to the Internet, disconnect the computer
from the network and the Internet.
- If you are running Windows Me or XP, turn off
System Restore. For instructions on how to turn off
System Restore, read your Windows documentation, or
one of the following articles:
- Locate the file that you just downloaded.
- Double-click the FixVundo.exe file
to start the removal tool.
- Click Start to begin the process, and then
allow the tool to run.
Important: Do not launch any
new applications while the tool is running.
- Restart the computer.
- Run the removal tool again to ensure that the
system is clean.
- If you are running Windows Me/XP, then re-enable
System Restore.
- If you are on a network or if you have a full-time
connection to the Internet, reconnect the computer to
the network or to the Internet connection.
- Run LiveUpdate to make sure that you are using the
most current virus definitions.
When the
tool has finished running, you will see a message
indicating whether Trojan.Vundo has infected the
computer. The tool displays results similar to the
following:
- Total number of the scanned files
- Number of deleted files
- Number of terminated viral processes
- Number of terminated viral threads
- Number of fixed registry
entries
What the tool
does
The Trojan.Vundo Removal Tool does the
following:
- Terminates the Trojan.Vundo processes
- Deletes the Trojan.Vundo files
- Deletes the registry values that the Trojan
added
Switches
The
following switches are designed for use by network
administrators:
Important:
Using the /MAPPED switch does not ensure the
complete removal of the virus on the remote computer,
because:
- The scanning of mapped drives scans only the
mapped folders. This may not include all the folders
on the remote computer, which can lead to missed
detections.
- If a viral file is detected on the mapped drive,
the removal will fail if a program on the remote
computer uses this file.
Therefore,
you should run the tool on every computer.
The
/EXCLUDE switch will only work with one path, not
multiple. An alternative is the /NOFILESCAN switch
followed by a manual scan with AntiVirus. This will let
the tool alter the registry. Then, scan the computer
with AntiVirus with current virus definitions. With
these steps, you should be able to clean the file
system.
The following is an example command line
that can be used to exclude a single
drive:
"C:\Documents and
Settings\user1\Desktop\FixVundo.exe"
/EXCLUDE=M:\
/LOG=c:\Vundo.txt
Alternatively,
the command line below will skip scanning the file
system, but will repair the registry modifications.
Then, run a regular scan of the system with proper
exclusions:
"C:\Documents and
Settings\user1\Desktop\FixVundo.exe"
/NOFILESCAN
/LOG=c:\Vundo.txt
Note: You
can give the log file any name and save it to any
location.
Digital signature
For
security purposes, FixVundo.exe is digitally
signed. Symantec recommends that you use only copies of
FixVundo.exe that have been directly downloaded
from the Symantec Security Response Web site.
If
you are not sure, or are a network administrator and
need to authenticate files before deployment, you should
check the authenticity of the digital
signature.
Follow these steps:
- Go to http://www.wmsoftware.com/free.htm.
- Download and save the Chktrust.exe file to the
same folder in which you saved
FixVundo.exe.
Note: Most of the
following steps are done at a command prompt. If you
downloaded the removal tool to the Windows desktop, it
will be easier if you first move the tool to the root
of the C drive. Then save the Chktrust.exe file to the
root of C as well.
(Step 3 to assume that both
the removal tool and Chktrust.exe are in the root of
the C drive.)
- Click Start > Run.
- Type one of the following:
- Windows
95/98/Me:
command
- Windows
NT/2000/XP:
cmd
- Click OK.
- In the command window, type the following,
pressing Enter after typing each
line:
cd\
cd downloads
chktrust -i
FixVundo.exe
You should see the
message:
Do you want to install and run
"Trojan.Vundo Removal Tool"
signed on 11/25/2004 10:01 AM
and distributed by Symantec
Corporation?
Note
- The date and time displayed in this dialog box
will be adjusted to your time zone, if your computer
is not set to the Pacific time zone.
- If you are using Daylight Saving time, the
displayed time will be exactly one hour earlier.
- If this dialog box does not appear, there are
two possible reasons:
- The tool is not from Symantec: Unless you are
sure that the tool is legitimate and that you
downloaded it from the legitimate Symantec Web
site, you should not run it.
- The tool is from Symantec and is legitimate:
However, your operating system was previously
instructed to always trust content from Symantec.
For information on this and on how to view the
confirmation dialog again, read the document, "How
to restore the Publisher Authenticity confirmation
dialog box."
- Click Yes to close the dialog box.
- Type exit, and then press Enter.
(This will close the MS-DOS session.)
Revision History:
- November 25, 2004: Published version 1.2.4 to
support removal of minor variants.
- November 22, 2004: Initial revision posted to
support removal of Trojan.Vundo.
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