Malicious Software Encyclopedia: Win32/Mywife
Published:
November 8, 2005
Win32/Mywife is a family of mass-mailing network worms that targets certain versions of Microsoft Windows. The worm spreads through e-mail attachments and writeable network shares.
On This Page
Threat Overview
| Class/type | Worm - Mass Mailer
Worm - Network
|
| Discovered | September 21, 2005 |
| Circulating | Yes |
| Affected operating systems | Windows NT 3.x
Windows NT 4.0
Windows 95
Windows 2000
Windows XP
Windows Server 2003
Windows ME
Windows 98
|
| Affected software |
Not specified
|
| Infection rating | Low |
| Recovery difficulty | Moderate |
| Damage rating | Medium |
| Transmission rating | Low |
Aliases (Also Known As)
Different antivirus vendors may be using different names to refer to this malicious software. Here are some of the names currently in use by antivirus software vendors participating in the Microsoft Virus Information Alliance (VIA):
CA:
Win32.BlackmalKaspersky:
I-Worm.Nyxem McAfee:
W32/MyWifePanda:
W32/MywifeSophos:
W32/NyxemSymantec:
W32.Blackmal@mmTrend Micro:
WORM_BLUEWORM
Learn more about the
Microsoft Virus Information Alliance.
Technical Analysis
Win32/Mywife can create numerous copies of itself with names like "sound_223.mp3<multiple spaces>.scr" and "Video_live.mpg<multiple spaces>.exe". The worm disguises the copies in two ways to make it appear that they are not executable files. First, the icon for the file may resemble the RealNetworks RealOne icon. Second, the file can have a double extension. The first extension may indicate a multimedia file, such as .mp3 or .wav. The second extension indicates an executable file, but there may be so many spaces between the two extensions that the second extension is not readily visible in a file list.
The worm adds data to the registry so that the worm runs each time Windows starts. The worm continually refreshes the registry with this data in case the data is changed. The worm also places a setting in the registry that causes the telnet service to start automatically when Windows starts.
The worm modifies or deletes files and registry keys associated with certain computer security-related applications. This prevents these applications from running when Windows starts.
Win32/Mywife can spread by copying itself to writeable network shares. It also spreads by sending a copy or archive of itself as an attachment to e-mail addresses found on the infected computer. The attachment may have multiple extensions, such as .XP2002.Zip.scr. The archive may include a text file named about.txt or a graphics file with a name such as Vide01.jpg.
How to Prevent Infection
Take the following steps to help prevent infection on your system:
Enable a firewall on your computer.
Get the latest computer updates.
Use up-to-date antivirus software.
Use caution with unknown attachments.
Use strong passwords.
Remove unneeded network shares.
Enable a firewall on your computer
Use a third-party firewall product or turn on the Microsoft Windows XP Internet Connection Firewall.
To turn on the Internet Connection Firewall in Windows XP
Click Start, and click Control Panel.
Click Network and Internet Connections, and click Network Connections. If you do not see Network and Internet Connections, click Switch to Category View.
Highlight a connection that you want to help protect, and click Change settings of this connection.
Click Advanced, and select Protect my computer and network by limiting or preventing access to this computer from the Internet.
Click OK.
Get the latest computer updates
Updates help protect your computer from viruses, worms, and other threats as they are discovered. You can use the Automatic Updates feature in Microsoft Windows XP to automatically download future Microsoft security updates while your computer is on and connected to the Internet.
To turn on Automatic Updates in Windows XP
Click Start, and click Control Panel.
Click Performance and Maintenance. If you do not see Performance and Maintenance, click Switch to Category View.
Click System.
Click Automatic Updates, and select Keep my computer up to date.
Select a setting. Microsoft recommends selecting Automatically download the updates, and install them on the schedule that I specify and setting a regular update time.
If you choose to have Automatic Updates notify you in step 5, you will see a notification balloon when new downloads are available to install. Click the notification balloon to review and install updates.
Use up-to-date antivirus software
Most antivirus software can detect and prevent infection by known malicious software. You should always run antivirus software on your computer that is updated with the latest signature files to automatically help protect you from infection. If you don't have antivirus software installed, you can get it from one of several companies. For more information, see http://www.microsoft.com/athome/security/downloads/default.mspx
Use caution with unknown attachments
Use caution before opening unknown e-mail or IM attachments, even if you know the sender. If you cannot confirm with the sender that a message is valid and that an attachment is safe, delete the message immediately, and run up-to-date antivirus software to check your computer for viruses.
Use strong passwords
A strong password has at least eight characters and includes a combination of letters, numbers, and symbols. It is easy for you to remember, but difficult for others to guess. Weak passwords include any words in the dictionary, names, dates, consecutive letters or numbers, common words with symbol substitutions (for example, p@ssw0rd), and so on.
Remove unneeded network shares
Malicious software can often spread over network shares. Remove unneeded network shares that are mapped to your computer.
To remove network shares in Windows XP
On the Start menu, click My Computer.
On the Tools menu, click Disconnect Network Drives…
In the Disconnect Network Drives dialog box, click the drives to disconnect and click OK.
How to Tell If Your Computer Is Infected
Win32/Mywife creates copies of itself with the following icon, which resembles the icon for RealOne Player files:
How to Recover from Infection
Automatic Recovery
To attempt to automatically remove this threat, run one of the following removal tools:
Transmission Methods
| Method | Description |
|---|
| Network Shares | Copies itself to writeable network shares. |
| Mass Mailer | Sends a copy of itself as an e-mail attachment to e-mail addresses found on the infected computer. |
| Social Engineering | May use a multiple extension for the e-mail attachment to make it appear that opening the attachment is safe. Uses a deceptive icon for worm-file copies to make it appear that opening the file is safe. |
Payload Information
| Payload type | Trigger | Description |
|---|
| Creates files | Execution | May create numerous copies of itself in %windir%\system32, such as:
sound_223.mp3<multiple spaces>.scr
movie_05.MP3<multiple spaces>.exe
PaltlkRoom.wav<multiple spaces>.scr
Video_live.mpg<multiple spaces>.exe May drop files such as:
%windir%\system32\About_BlackWorm.C.txt
%windir%\system32\OSSMTP.dll
%windir%\system32\Vide01.jpg
|
| Compromises Security | Execution | Modifies or deletes files and registry keys associated with certain computer security-related applications. |
