Encyclopedia entry: Worm:Win32/Neeris.AN - Learn more about malware

Worm:Win32/Neeris.AN is a worm that spreads by removable drives and by attempting to exploit a number of particular vulnerabilities. The worm also contains backdoor functionality that allows unauthorized access and control of the affected computer.

System changes

The following system changes may indicate the presence of this malware:

The presence of the following files:
c:\windows\system32\csrsc.exe
The presence of the following registry modifications:
Adds value: "%windir%\system\csrsc.exe"

With data: "%windir%\system\csrsc.exe:*:microsoft enabled"

To subkey: HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List

Worm:Win32/Neeris.AN is a worm that spreads by removable drives and by attempting to exploit a number of particular vulnerabilities. The worm also contains backdoor functionality that allows unauthorized access and control of the affected computer.

Installation

When executed, the worm copies itself to the following location:

c:\windows\system32\csrsc.exe

Spreads via…

Network and removable drives

Worm:Win32/Neeris.AN may attempt to spread via removable drives. It does this by creating a directory called RECYCLER in the root of the removable drive. In then creates another directory underneath that with a name such as 2434476501-1644491937-600003330-1213. The worm copies itself into this directory, with the file name “autorunme.exe”. For example:

E:\RECYCLER\S-1-6-21-2434476501-1644491937-600003330-1213\autorunme.exe

The worm also creates an autorun.inf file in the root directory of the drive in order to launch the worm if, for example, the drive is connected to another machine.

The worm sets the hidden and system attributes for all of the aforementioned directories and files.

Exploits

Worm:Win32/Neeris.AN also attempts to spread by generating IP address in its local network and attempting to exploit systems unpatched against the vulnerabilities addressed in the following Microsoft Security Bulletins

Neeris.AN also targets computers running Microsoft SQL. It attempts to log on to these computers by exploiting weak passwords utilizing the following list of passwords and usernames that it carries in its code:

007

1

12

123

1234

12345

123456

1234567

12345678

123456789

1234567890

2000

2001

2002

2003

2004

access

accounting

accounts

adm

admin

administrador

administrat

administrateur

administrator

admins

asd

backup

bill

bitch

blank

bob

brian

changeme

chris

cisco

compaq

control

data

database

databasepass

databasepassword

db1

db1234

db2

dbpass

dbpassword

default

dell

demo

domain

domainpass

domainpassword

eric

exchange

fred

f*ck

george

god

guest

hell

hello

home

homeuser

hp

ian

ibm

internet

intranet

jen

joe

john

kate

katie

lan

lee

linux

login

loginpass

luke

mail

main

mary

mike

neil

nokia

none

null

oem

oeminstall

oemuser

office

oracle

orainstall

outlook

pass

pass1234

passwd

password

password1

peter

pwd

qaz

qwe

qwerty

root

sa

sam

server

sex

siemens

slut

sql

sqlpassoainstall

staff

student

sue

susan

system

teacher

technical

test

unix

user

web

win2000

win2k

win98

windows

winnt

winpass

winxp

www

zxc

Payload

Allows backdoor access and control: TCP port 445

Worm:Win32/Neeris.AN attempts to connect to a particular IRC server at gg.arrancar.org using TCP Port 445. It joins a channel and waits for commands. Using this backdoor, an attacker can perform the following actions on an affected machine:

remove itself
join another IRC channel
download and execute arbitrary files

Modifies system settings

Worm:Win32/Neeris.AN modifies the following registry entry to allow its copy to bypass the Windows Firewall:

Adds value: "%windir%\system\csrsc.exe"

With data: "%windir%\system\csrsc.exe:*:microsoft enabled"

To subkey: HKLM\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List

Analysis by Jaime Wong

Take the following steps to help prevent infection on your system:

Enable a firewall on your computer.
Get the latest computer updates for all your installed software.
Use up-to-date antivirus software.
Use caution when opening attachments and accepting file transfers.
Use caution when clicking on links to web pages.
Avoid downloading pirated software.
Protect yourself against social engineering attacks.
Use strong passwords.

Enable a firewall on your computer

Use a third-party firewall product or turn on the Microsoft Windows Internet Connection Firewall.

To turn on the Windows Firewall in Windows Vista

Click Start, and click Control Panel.
Click Security.
Click Turn Windows Firewall on or off.
Select On.
Click OK.

To turn on the Internet Connection Firewall in Windows XP

Click Start, and click Control Panel.
Click Network and Internet Connections. If you do not see Network and Internet Connections, click Switch to Category View.
Click Change Windows Firewall Settings.
Select On.
Click OK.

Get the latest computer updates

Updates help protect your computer from viruses, worms, and other threats as they are discovered. It is important to install updates for all the software that is installed in your computer. These are usually available from vendor websites.

You can use the Automatic Updates feature in Windows to automatically download future Microsoft security updates while your computer is on and connected to the Internet.

To turn on Automatic Updates in Windows Vista

Click Start, and click Control Panel.
Click System and Maintainance.
Click Windows Updates.
Select a setting. Microsoft recommends selecting Install updates automatically and choose a time that is convenient for you. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.

To turn on Automatic Updates in Windows XP

Click Start, and click Control Panel.
Click System.
Click Automatic Updates.
Select a setting. Microsoft recommends selecting Automatic. If you do not choose Automatic, but you choose to be notified when updates are ready, a notification balloon appears when new downloads are available to install. Click the notification balloon to review and install the updates.

Use up-to-date antivirus software

Most antivirus software can detect and prevent infection by known malicious software. To help protect you from infection, you should always run antivirus software, such as Microsoft Security Essentials, that is updated with the latest signature files. For more information, see http://www.microsoft.com/protect/computer/viruses/vista.mspx.

Use caution when opening attachments and accepting file transfers

Exercise caution with e-mail and attachments received from unknown sources, or received unexpectedly from known sources. Use extreme caution when accepting file transfers from known or unknown sources.

Use caution when clicking on links to Web pages

Exercise caution with links to web pages that you receive from unknown sources, especially if the links are to a Web page that you are not familiar with, unsure of the destination of, or suspicious of. Malicious software may be installed in your system simply by visiting a Web page with harmful content.

Avoid downloading pirated software

Threats may also be bundled with software and files that are available for download on various torrent sites. Downloading "cracked" or "pirated" software from these sites carries not only the risk of being infected with malware, but is also illegal. For more information, see 'The risks of obtaining and using pirated software'.

Protect yourself from social engineering attacks

While attackers may attempt to exploit vulnerabilities in hardware or software in order to compromise a system, they also attempt to exploit vulnerabilities in human behavior in order to do the same. When an attacker attempts to take advantage of human behavior in order to persuade the affected user to perform an action of the attacker's choice, it is known as 'social engineering'. Essentially, social engineering is an attack against the human interface of the targeted system. For more information, see 'What is social engineering?'.

Use strong passwords

Attackers may try to gain access to your Windows account by guessing your password. It is therefore important that you use a strong password – one that cannot be easily guessed by an attacker. A strong password is one that has at least 8 characters, and combines letters, numbers, and symbols. For more information, see http://www.microsoft.com/protect/yourself/password/create.mspx.

Manual removal is not recommended for this threat. To detect and remove this threat and other malicious software that may have been installed, run a full-system scan with an up-to-date antivirus product such as Microsoft Security Essentials, or the Windows Live OneCare safety scanner. For more information about using antivirus software, see http://www.microsoft.com/security/antivirus/av.aspx.

Recovering from recurring infections on a network

The following additional steps may need to be taken to completely remove this threat from an infected network, and to stop infections from recurring from this and other similar types of network-spreading malware:

Ensure that an antivirus product is installed on ALL machines connected to the network that can access or host shares (see above for further detail).
Ensure that all available network shares are scanned with an up-to-date antivirus product.
Restrict permissions as appropriate for network shares on your network. For more information on simple access control, please see: http://technet.microsoft.com/en-us/library/bb456977.aspx.
Remove any unnecessary network shares or mapped drives.

Note: Additionally it may be necessary to temporarily change the permission on network shares to read-only until the disinfection process is complete.

Additional recovery instructions for Worm:Win32/Neeris.AN

This threat may make lasting changes to an affected system’s configuration that will NOT be restored by detecting and removing this threat. For more information on returning an affected system to its pre-infected state, please see the following article/s:

Viewing hidden and/or system files:

For Windows Vista: http://windowshelp.microsoft.com/
For Windows XP: http://www.microsoft.com/windowsxp/using/helpandsupport/learnmore/tips/hiddenfiles.mspx

Enabling Windows Firewall:

For Windows Vista: http://windowshelp.microsoft.com/Windows/en-US/help/bfe523a9-7eec-4d3f-add1-2f68b9cfa1c01033.mspx
For Windows XP: http://support.microsoft.com/kb/283673

Get the latest computer updates

This worm attempts to exploit several previously addressed vulnerabilities. In order to ensure that your computer is not vulnerable to these exploits, you must download and install the appropriate updates.