-----Original Message-----
Windows keeps locking up on me.
When I manage to bring up Task Manager it shows the CPU at 100% with
Rundll32.dll process chewing up most of the CPU capacity.
What the -- is this ?
How do I rid of it?
HHHHELP
.
Looks like you have a worm? Sorry!
W32.Netspree.Worm
Discovered on: January 22, 2003
Last Updated on: January 23, 2003 06:16:00 AM
W32.Netspree.Worm is a worm that spreads over the network
shares that are protected with trivial passwords.
W32.Netspree.Worm also uses IRC to notify the remote
attackers when it infects a new system. This action may
allow a hacker to download programs to the infected
computer. The worm may also enable the hacker to use the
infected computer as a drone for attacks against other
internet-connected computers.
W32.Netspree.Worm does not spread from Windows 95/98/Me
systems, although it functions normally in every other
way on those platforms.
Type: Worm
Infection Length: 70,656 bytes, 61,440 bytes, 48,448
bytes, 35,840 bytes, 1,613 bytes
Systems Affected: Windows 95, Windows 98, Windows NT,
Windows 2000, Windows XP, Windows Me
Systems Not Affected: Windows 3.x, Macintosh, OS/2,
UNIX, Linux
Beta Virus Definitions
January 22, 2003
Virus Definitions (Intelligent Updater) *
January 23, 2003
Virus Definitions (LiveUpdateT) **
January 29, 2003
*
Intelligent Updater definitions are released daily, but
require manual download and installation.
Click here to download manually.
**
LiveUpdate virus definitions are usually released every
Wednesday.
Click here for instructions on using LiveUpdate.
Wild:
Number of infections: 0 - 49
Number of sites: 0 - 2
Geographical distribution: Low
Threat containment: Easy
Removal: Easy
Threat Metrics
Wild:
Low
Damage:
Low
Distribution:
Low
The W32.Netspree.Worm consists of these files:
Lcp_Netbios.dll
Psexec.bat
Psexec.exe (A Sysinternals remote execution tool)
Psexecsvc.exe (A portion of Psexec.exe)
Win32load.exe
The Lcp_Netbios.dll, Psexec.bat, and Win32load.exe files
are described in detail below.
Notes:
Psexec.exe and Psexecsvc.exe are not malicious, and
Symantec antivirus products will not detect them as such.
These files will normally be copied to the %System%
folder.
%System% is a variable. The worm locates the System
folder and copies the files to that location. By default,
this is C:\Windows\System (Windows 95/98/Me),
C:\Winnt\System32 (Windows NT/2000), or
C:\Windows\System32 (Windows XP).
Lcp_Netbios.dll
Lcp_netbios.dll is an NT service that contains the other
four files. Lcp_netbios.dll inserts the files on your
system, and then executes Psexec.bat.
Psexec.bat
Psexec.bat is a simple batch file that takes in, as an
argument, the system IP address to be probed.
Psexec.bat consists of approximately 40 lines of this
text:
"net use \\%1\ipc$ <some password> /user:<some user name>"
which probes the IPC$ using trivial user/password
combinations (including username/nopassword). Then, it is
terminated with a few lines that uses the Psexec.exe file
to copy Win32load.exe to the remote system, and then
executes it. This will only succeed if an open IPC$ share
is found.
The destination folder of the Win32load.exe file is %
windir%\System32 and is hardcoded into the Psexec.exe
utility.
WIN32LOAD.EXE
When Win32load.exe is executed, it:
Copies itself to the %system% folder, and then executes
the copied file.
Creates the registry value:
Windows SubSys "<current execution path>\WIN32LOAD.EXE"
rundll32.dll,loadsubsys,loadsys,win32
under the registry keys:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersi
on\Run
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersi
on\RunServices
Sets the registry value:
restrictanonymous DWORD:0
under the registry key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
Win32load.exe will wait for an active Internet
connection. When one is found, it connects to the IRC
server master.leet-gamer.net through port 6,667 and joins
the channel #lc_breed using a hardcoded password. Then,
Win32load.exe will announce its presence divulging
information (to anyone who wants to listen) regarding
vital information about the infected computer, including
the IP address, system type, operating system, cpu type,
and so on.
Win32load.exe also contains rudimentary remote control
functionality allowing for file downloading and
execution. It also allows the computer to be used as a
drone in a joint DoS attack against other Internet-
connected computers.
Downloads and executes Lcp_netbios.dll from a remote
Internet site so that the cycle can continue.
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, 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.
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.
These instructions pertain to all current and recent
Symantec antivirus products, including the Symantec
AntiVirus and Norton AntiVirus product lines.
Update the virus definitions.
Do one of the following:
Windows 95/98/Me: Restart the computer in Safe mode.
Windows NT/2000/XP: End the Trojan process.
Run a full system scan and delete all the files detected
as W32.Netspree.Worm.
Reverse the changes that the Trojan made to the registry.
For details on each of these procedures, read the
following instructions.
1. Updating the virus definitions
Symantec Security Response fully tests all the virus
definitions for quality assurance before they are posted
to our servers. There are two ways to obtain the most
recent virus definitions:
Running LiveUpdate, which is the easiest way to obtain
the virus definitions. These virus definitions are posted
to the LiveUpdate servers once each week (usually on
Wednesdays), unless there is a major virus outbreak. To
determine whether definitions for this threat are
available by LiveUpdate, refer to the Virus Definitions
(LiveUpdate), in the "Protection" section, at the top of
this writeup.
Downloading the definitions using the Intelligent
Updater. The Intelligent Updater virus definitions are
posted on U.S. business days (Monday through Friday). You
should download the definitions from the Symantec
Security Response Web site and manually install them. To
determine whether definitions for this threat are
available by the Intelligent Updater, refer to the Virus
Definitions (Intelligent Updater), in the "Protection"
section, at the top of this writeup.
The Intelligent Updater virus definitions are available
here. For detailed instructions on how to download and
install the Intelligent Updater virus definitions from
the Symantec Security Response Web site, click here.
2. Restarting the computer in Safe mode or ending the
Trojan process
Windows 95/98/Me
Restart the computer in Safe mode. All the Windows 32-bit
operating systems, except for Windows NT, can be
restarted in Safe mode. For instructions on how to do
this, read the document, "How to start the computer in
Safe Mode."
Windows NT/2000/XP
To end the Trojan process:
Press Ctrl+Alt+Delete once.
Click Task Manager.
Click the Processes tab.
Double-click the Image Name column header to
alphabetically sort the processes.
Scroll through the list and look for Win32load.
If you find the file, click it, and then click End
Process.
Exit the Task Manager.
3. Scanning for and deleting the infected files
Start your Symantec antivirus program and make sure that
it is configured to scan all the files.
For Norton AntiVirus consumer products: Read the
document, "How to configure Norton AntiVirus to scan all
files."
For Symantec AntiVirus Enterprise products: Read the
document, "How to verify that a Symantec Corporate
antivirus product is set to scan All Files."
Run a full system scan.
If any files are detected as infected with
W32.Netspree.Worm, click Delete.
4. Reversing the changes made to the registry
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 the specified keys only. Read
the document, "How to make a backup of the Windows
registry," for instructions.
Click Start, and then click Run. (The Run dialog box
appears.)
Type regedit, and then click OK. (The Registry Editor
opens.)
Navigate to the key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersi
on\Run
In the right pane, delete the value:
Windows SubSys
Navigate to the key:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersi
on\Runservices
NOTE: This key will not exist on all systems.
In the right pane, delete the value:
Windows SubSys
Navigate to the key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
In the right pane, double-click:
restrictanonymous
Change the value to:
DWORD:1
Exit the Registry Editor
Anti-Virus sites
<
http://www.symantec.com>
<
http://www.pandasoftware.com>
<
http://www.trendmicro.com>
<
http://www.mcafee.com>
<
http://www.sophos.com>
