W32.Inforyou.A@mm

SUMMARY

W32.Inforyou.A@mm is a mass-mailing worm that sends itself to email addresses gathered from the compromised computer using its own SMTP engine. The email has a variable subject and attachment name. The attachment will have a .pif, .scr, .exe, or .zip extension.

Protection

• Virus Definitions (LiveUpdate™ Weekly) February 27, 2005
• Virus Definitions (Intelligent Updater) February 25, 2005

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Moderate

Damage

• Damage Level: Low
• Payload Trigger: Performs denial of service attacks.
• Large Scale E-mailing: Sends an email to addresses gathered from the compromised computer.
• Degrades Performance: Attempts to perform Denial of Service attacks against numerous hosts which may degrade system performance.

Distribution

• Distribution Level: High
• Subject of Email: Varies.
• Name of Attachment: Varies.

TECHNICAL DETAILS

Once W32.Inforyou.A@mm is executed, it performs the following actions:

1. Creates a copy of itself as %System%[random].exe
   
   Note: %System% is a variable that refers to the System folder. By default this is C:WindowsSystem (Windows 95/98/Me), C:WinntSystem32 (Windows NT/2000), or C:WindowsSystem32 (Windows XP).
   
   
2. Drops the following files:
   
   
   • %System%MSDevBase.dat
   • %System%[random file name].dll
     
     Notes:
   • The worm uses MSDevBase.dat to store harvested email addresses.
   • [random file name].dll is registered as a COM reference and is used to load this worm executable file every time Windows starts.
     
     
3. Adds the value:
   
   "ShellServiceObjectDelayLoad.Net Framework" = "{3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}"
   
   to the registry subkey:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   
   so that the worm is executed every time Windows starts.
   
   
4. Adds the value:
   
   "InProcServer32@" = "%System32%.dll"
   
   to the registry subkeys:
   
   HKEY_LOCAL_MACHINESoftwareClassesCLSID{3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}
   HKEY_CLASSES_ROOTCLSID{3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}
   
   so that the worm is executed every time Windows starts.
   
   
5. Creates the mutex MS.NETFmwk1.1 to ensure that only one instance of the worm is executed on the computer.
   
   
6. Performs denial of service attacks by sending multiple HTTP requests to the following domains:
   
   
   • 50sbrotherhood.com/ikAARBbH
   • anypets.com/sotNuSLd
   • bcn4life.com/KMjvnkAc
   • beeslender.com/LzKDMFVx
   • cambodiaclassic.com/tAnwLRRp
   • divasonic.com/zDcdWXDA
   • fresh895fm.com/JnaCMJGA
   • galeriass.com/mRDxxkyz
   • hpbyggematrialer.dk/jEoESVah
   • hydrocut.com/KzfDvbjk
   • linux-bulgaria.org/ZPImndAd
   • opticalinstrument.com.cn/OfRRnhYY
   • organicbabe.com.au/QoGJQIZV
   • pbwga.com/KJvaslsl
   • piraten.dk/BGAiQOtB
   • pitzmedia.com/AGgRBzQd
   • poemas-de-amor.org/sQAAXWrE
   • praha-mesto.cz/VeTBmiUj
   • sakichan.ho8.com/KDCvKLFh
   • smirkingchimp.com/lldLmfSD
   • snodgers.com/zmvIKkla
   • synodcathedral.org/KVrxusoL
   • therefrisky.com/kjnvaPPa
   • usdacrc.com/gGVrsjlh
   • wildrice.com/kdmvflkz
   • wolfscreek.com/lOnFQYoO
   • asis.com/LMlakmvb
   • cashetta.com/LlksvIJH
   • divasonic.com/zDcdWXDA
   • lysbordet.com/OJJAtUEo
   • pitzmedia.com/AGgRBzQd
     
     
     
7. Spreads via email by sending an email to addresses gathered from the compromised computer. The email will have the following characteristics:
   
   From: Spoofed
   
   Subject:
   Varies. May be one of the following:
   
   
   • Their image.
   • Update your credit client program.
   • Take update of credit access program.
   • My username descriptions.
   • His photo.
   • cyber porno art
   • My West Coast Bank registration data disabled.
     
     

Message:
(One of the following)


• Greetings, do you remember you spoke something about their image in a naked kind?
  I have found a little bit, i don`t know it is pleasant to you whether or not but i have decided to give to see it to you
  magic wordJM3QkMRg8X906).
  As you will decide to have a rest with me, call.
  winxp.
• Hello, my name is , i am from branch of State Central Bank.
  Too hour ago my manager, has asked me to notify you about that our firm has released the new version of credit client program,
  unfortunately to send the program from work i have not had time therefore i send file from home. Information about account
  program inside package.
  Don`t forget unlock pass is AmoE4fI2s15L46.
  I am sorry, .
  Dear Jack, you ask me about our registration reports and i send it to you
  Also i found some interesting info about our budget usage, if you have free minute please familiarize with this report.
  You should remember this personal information only for you, access code is :60pyFm2JcQ2g0gC. Your data i package file.
  ***
  
  
Attachment:
The attachment name will be one of the following with a .pif, .scr, .exe, or .zip extension:


• ###adult
• ##-photo
• #HardArt
• #MyPhoto
• #Sex.jpg
• Applic-#
• Art-####
• AssFuck#
• Blondes#
• Blowjobs
• CKeeper#
• Credit##
• details#
• Dildos##
• Fucking#
• Girls-##
• HardCor#
• Image###
• Image-##
• Inf-####
• Inf4You#
• InfNo###
• info-###
• ItsMe-##
• Keeper##
• Lesbian#
• Me-#####
• MKeep###
• MKp##Upd
• MoneyKe#
• MyImage#
• MyPhoto#
• NudeGirl
• NWUpdate
• Orgy####
• Photo###
• Porn-###
• Porno-##
• PornStar
• Pussy###
• Rep-####
• report##
• PInform#
• Program#
• Sadomaso
• SecRep##
• SInfo###
• SoftCor#
• Teens-##
• Update##
• vibrator
• Xxx#.jpg
• YouAndI#
• Your-###
• YourRep#
  
  Notes:
• # denotes a random number.
• The attachment may be an executable file or a password-protected .ZIP file.

Recommendations

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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.

REMOVAL

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan and delete all the files detected as W32.Inforyou.A@mm.
4. Delete the value that was added to the registry.
   

For specific details on each of these steps, read the following instructions.

1. To disable System Restore (Windows Me/XP)
If you are running Windows Me or Windows XP, we recommend that you temporarily turn off System Restore. Windows Me/XP uses this feature, which is enabled by default, to restore the files on your computer in case they become damaged. If a virus, worm, or Trojan infects a computer, System Restore may back up the virus, worm, or Trojan on the computer.

Windows prevents outside programs, including antivirus programs, from modifying System Restore. Therefore, antivirus programs or tools cannot remove threats in the System Restore folder. As a result, System Restore has the potential of restoring an infected file on your computer, even after you have cleaned the infected files from all the other locations.

Also, a virus scan may detect a threat in the System Restore folder even though you have removed the threat.

For instructions on how to turn off System Restore, read your Windows documentation, or one of the following articles:

• "How to disable or enable Windows Me System Restore"
• "How to turn off or turn on Windows XP System Restore"

Note: When you are completely finished with the removal procedure and are satisfied that the threat has been removed, re-enable System Restore by following the instructions in the aforementioned documents.

For additional information, and an alternative to disabling Windows Me System Restore, see the Microsoft Knowledge Base article, "Antivirus Tools Cannot Clean Infected Files in the _Restore Folder," Article ID: Q263455.


2. To update 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 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).
• Downloading the definitions using the Intelligent Updater: The Intelligent Updater virus definitions are posted daily. 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).
  
  The Intelligent Updater virus definitions are available: Read "How to update virus definition files using the Intelligent Updater" for detailed instructions.

3. To scan for and delete the infected files

1. 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."
2. Run a full system scan.
3. If any files are detected as infected with W32.Inforyou.A@mm, click Delete.
   
   Note: If your Symantec antivirus product reports that it cannot delete an infected file, Windows may be using the file. To fix this, run the scan in Safe mode. For instructions, read the document, "How to start the computer in Safe Mode." Once you have restarted in Safe mode, run the scan again.
   
   After the files are deleted, restart the computer in Normal mode and proceed with section 4.
   

4. To delete the value from the registry
Important: Symantec strongly recommends that you back up the registry before making any changes to it. Incorrect changes to the registry can result in permanent data loss or corrupted files. Modify the specified subkeys only. Read the document, "How to make a backup of the Windows registry," for instructions.

1. Click Start > Run.
2. Type regedit
   
   Then click OK.
   
   
3. Navigate to the subkey:
   
   HKEY_LOCAL_MACHINESoftwareMicrosoftWindowsCurrentVersion
   
   
4. In the right pane, delete the value:
   
   "ShellServiceObjectDelayLoad.Net Framework" = "{3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}"
   
   
5. Navigate to the subkeys:
   
   HKEY_LOCAL_MACHINESoftwareClassesCLSID
   {3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}
   HKEY_CLASSES_ROOTCLSID{3845CD5A-6FA0-3E0C-3980-000CD8DE3A31}
   
   
6. In the right pane, delete the value:
   
   "InProcServer32@" = "%System32%.dll"
   
   
7. Exit the Registry Editor.