W32.Dinfor.D.Worm

1. Copies itself as %System%\intspvc.exe, and then executes the file.
   
   

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   Note: %System% is a variable: The worm locates the System folder and copies itself 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).
   

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2. Creates the following files:
   • %Temp%\b.bat: A malicious batch file detected as W32.Dinfor.D.Worm.
   • %System%\Runtime.bat: A malicious batch file detected as W32.Dinfor.D.Worm.
   • %System%\Svhost32.exe. A legitimate utility named PsExec, which has been packed with UPX. Since this file is not malicious, Symantec antivirus products do not detect it.
     
     

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     Notes:
   • %System% is a variable: The worm locates the System folder and copies itself 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).
   • %Temp% is a variable: The worm locates the temporary folder and copies itself to that location. By default, this is C:\Windows\TEMP (Windows 95/98/Me), C:\WINNT\Temp (Windows NT/2000), or C:\Document and Settings\<UserName>\Local Settings\Temp (Windows XP).
     

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3. Adds the value:
   
   "Generic Host Process for Win32 Services"="intspvc.exe"
   
   to the registry keys:
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
   
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\
   RunServices
   
   so that the worm runs when you start Windows.
   
   
4. Creates a temp file containing the following security settings:
   
   [Version]
   signature="$ShawnsMind$"
   Revision=1
   [Profile Description]
   Description=Default Security Settings. (Windows 2000 Professional)
   [System Access]
   MinimumPasswordAge = 0
   MaximumPasswordAge = 42
   MinimumPasswordLength = 0
   PasswordComplexity = 0
   PasswordHistorySize = 0
   LockoutBadCount = 0
   RequireLogonToChangePassword = 0
   ClearTextPassword = 0
   [Event Audit]
   AuditSystemEvents = 0
   AuditLogonEvents = 0
   AuditObjectAccess = 0
   AuditPrivilegeUse = 0
   AuditPolicyChange = 0
   AuditAccountManage = 0
   AuditProcessTracking = 0
   AuditDSAccess = 0
   AuditAccountLogon = 0
   [Registry Values]
   machine\system\currentcontrolset\services\netlogon\parameters\signsecurechannel=4,1
   machine\system\currentcontrolset\services\netlogon\parameters\sealsecurechannel=4,1
   machine\system\currentcontrolset\services\netlogon\parameters\requirestrongkey=4,0
   machine\system\currentcontrolset\services\netlogon\parameters\requiresignorseal=4,0
   machine\system\currentcontrolset\services\netlogon\parameters\disablepasswordchange=4,0
   machine\system\currentcontrolset\services\lanmanworkstation\parameters\requiresecuritysignature=4,0
   machine\system\currentcontrolset\services\lanmanworkstation\parameters\enablesecuritysignature=4,1
   machine\system\currentcontrolset\services\lanmanworkstation\parameters\enableplaintextpassword=4,0
   machine\system\currentcontrolset\services\lanmanserver\parameters\requiresecuritysignature=4,0
   machine\system\currentcontrolset\services\lanmanserver\parameters\enablesecuritysignature=4,0
   machine\system\currentcontrolset\services\lanmanserver\parameters\enableforcedlogoff=4,1
   machine\system\currentcontrolset\services\lanmanserver\parameters\autodisconnect=4,15
   machine\system\currentcontrolset\control\session manager\protectionmode=4,1
   machine\system\currentcontrolset\control\session manager\memory management\clearpagefileatshutdown=4,0
   machine\system\currentcontrolset\control\print\providers\lanman print services\servers\addprinterdrivers=4,0
   machine\system\currentcontrolset\control\lsa\restrictanonymous=4,0
   machine\system\currentcontrolset\control\lsa\lmcompatibilitylevel=4,0
   machine\system\currentcontrolset\control\lsa\fullprivilegeauditing=3,0
   machine\system\currentcontrolset\control\lsa\crashonauditfail=4,0
   machine\system\currentcontrolset\control\lsa\auditbaseobjects=4,0
   machine\software\microsoft\windows\currentversion\policies\system\shutdownwithoutlogon=4,1
   machine\software\microsoft\windows\currentversion\policies\system\legalnoticetext=1,
   machine\software\microsoft\windows\currentversion\policies\system\legalnoticecaption=1,
   machine\software\microsoft\windows\currentversion\policies\system\dontdisplaylastusername=4,0
   machine\software\microsoft\windows nt\currentversion\winlogon\scremoveoption=1,0
   machine\software\microsoft\windows nt\currentversion\winlogon\passwordexpirywarning=4,14
   machine\software\microsoft\windows nt\currentversion\winlogon\cachedlogonscount=1,10
   machine\software\microsoft\windows nt\currentversion\winlogon\allocatefloppies=1,0
   machine\software\microsoft\windows nt\currentversion\winlogon\allocatedasd=1,0
   machine\software\microsoft\windows nt\currentversion\winlogon\allocatecdroms=1,0
   machine\software\microsoft\windows nt\currentversion\setup\recoveryconsole\setcommand=4,0
   machine\software\microsoft\windows nt\currentversion\setup\recoveryconsole\securitylevel=4,0
   [Privilege Rights]
   seassignprimarytokenprivilege =
   seauditprivilege =
   sebackupprivilege = *S-1-5-32-544,*S-1-5-32-551
   sebatchlogonright =
   sechangenotifyprivilege = *S-1-5-32-544,*S-1-5-32-551,*S-1-5-32-547,*S-1-5-32-545,*S-1-1-0
   secreatepagefileprivilege = *S-1-5-32-544
   secreatepermanentprivilege =
   secreatetokenprivilege =
   sedebugprivilege = *S-1-5-32-544
   sedenybatchlogonright =
   sedenyinteractivelogonright =
   sedenynetworklogonright =
   sedenyservicelogonright =
   seenabledelegationprivilege =
   seincreasebasepriorityprivilege = *S-1-5-32-544
   seincreasequotaprivilege = *S-1-5-32-544
   seinteractivelogonright =
   S-1-5-32-544,*S-1-5-32-551,*S-1-5-32-547,*S-1-5-32-545,*S-1-5-21-1960408961-1637723038-1801674531-501
   seloaddriverprivilege = *S-1-5-32-544
   selockmemoryprivilege =
   semachineaccountprivilege =
   senetworklogonright =
   seprofilesingleprocessprivilege = *S-1-5-32-544,*S-1-5-32-547
   seremoteshutdownprivilege = *S-1-5-32-544
   serestoreprivilege = *S-1-5-32-544,*S-1-5-32-551
   sesecurityprivilege = *S-1-5-32-544
   seservicelogonright =
   seshutdownprivilege = *S-1-5-32-544,*S-1-5-32-551,*S-1-5-32-547,*S-1-5-32-545
   sesyncagentprivilege =
   sesystemenvironmentprivilege = *S-1-5-32-544
   sesystemprofileprivilege = *S-1-5-32-544
   sesystemtimeprivilege = *S-1-5-32-544,*S-1-5-32-547
   setakeownershipprivilege = *S-1-5-32-544
   setcbprivilege =
   seundockprivilege = *S-1-5-32-544,*S-1-5-32-547,*S-1-5-32-545
   
   
5. Uses the following command to configure the security policy:
   
   secedit.exe /configure /areas USER_RIGHTS /db %temp%\temp.mdb /CFG temp
   
   
6. Uses the file, Runtime.bat, to spread itself to computers on the same network. Runtime.bat attempts to exploit weak user name/password combinations. This batch file will try to copy the worm as intspvc.exe into the following folders on the remote computer:
   • \C$\WINNT\All Users\Start Menu\Programs\Startup
   • \C\WINDOWS\Start Menu\Programs\Startup
   • \C$\Documents and Settings\All Users\Start Menu\Programs\Startup
     
     
7. Joins an IRC channel and waits for commands from a remote attacker. The attacker can:
   
   • Retrieve information about the infected host, such as the operating system version and the computer's hardware
   • Upload and download files
   • Execute files
   • Use the computer to perform Denial of Service (DoS) attacks on other computers

Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

• Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
• 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.
• Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
• Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
• Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
• Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
• If a 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate compromised computers quickly to prevent threats from spreading further. 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.
• If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
• For further information on the terms used in this document, please refer to the Security Response glossary.