W32.Rispif.A

Once executed, the worm creates some of the following files:

• C:\lo.tmp
• %SYSTEM%\wuauclt.exe
• %SYSTEM%\dllcache\wuauclt.exe
• %SYSTEM%\wsotdet.dll
• %SYSTEM%\wssndet.dll

It spreads across fixed and removable drives from C-Z by creating some of the following files:

• C:\AUTORUN.INF
• C:\RIS.PIF (copy of the worm)
• C:\RVS.PIF (copy of the worm)

The worm creates the following registry entry, so that it runs every time Windows starts:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\policies\explorer\run\"explorer" = "%System%\wuauclt.exe"

It creates the following mutex so only one instance of the worm is running on the compromised computer:
CNNLAST

It then changes the system date by setting the year back to 2004.

The worm temporarily overwrites the following file to run a kernel mode component:
%System%\drivers\beep.sys

The kernel mode component is detected as Hacktool.Rootkit and it uses rootkit functionalities to restore KeServiceDescriptorTable to the original values and disable security softwares.

It runs the Windows CACLS.EXE tool to change permissions for the following files and enables the use of WinPCAP libraries to any user on the compromised computer:

• c:\windows\system32\packet.dll
• c:\windows\system32\pthreadVNC.dll
• c:\windows\system32\drivers\npf.sys
• c:\windows\system32\drivers\npptools.dll
• c:\windows\system32\drivers\acpidisk.sys
• c:\windows\system32\drivers\wanpacket

The worm may perform ARP injection or may download a component to do so.

It modifies the following registry entries to disable security programs and tools:

• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\360rpt.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\360safe.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\360safebox.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\360tray.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\ANTIARP.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Ast.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AutoRunKiller.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AvMonitor.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AVP.COM\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\AVP.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\CCenter.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Frameworkservice.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\GFUpd.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\GuardField.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\IceSword.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Iparmor.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KASARP.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KAVPFW.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\kavstart.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\kmailmon.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KRegEx.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KVMonxp.KXP\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KVSrvXP.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\KVWSC.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\kwatch.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Mmsk.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\msconfig.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Navapsvc.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\nod32krn.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Nod32kui.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RAV.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\RavStub.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Regedit.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\rfwmain.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\rfwProxy.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\rfwsrv.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\rfwstub.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\Runiep.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\safeboxTray.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\SREngLdr.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\VPC32.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\VPTRAY.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"
• HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\WOPTILITIES.EXE\"debugger" = "%System%\dllcache\wuauclt.exe"

It tries to end the following processes which may be security-related:

• 360rpt.exe
• 360Safe.exe
• 360tray.exe
• AntiArp.exe
• Avp.exe
• CCenter.exe
• FrameworkService.exe
• GFUpd.exe
• GuardField.exe
• Iparmor.exe
• KASARP.exe
• KAVPFW.EXE
• kavstart.exe
• kmailmon.exe
• KRegEx.exe
• kvsrvxp.exe
• kvsrvxp.kxp
• KVWSC.EXE
• KvXP.kxp
• kwatch.exe
• nod32krn.exe
• nod32kui.exe
• Rav.exe
• RAVMON.exe
• RavStub.exe
• Ravxp.exe
• rfwmain.exe
• rfwProxy.exe
• rfwsrv.exe
• rfwstub.exe
• Runiep.exe
• scan32.exe
• TBMon.exe
• UpdaterUI.exe
• VPC32.exe
• VPTRAY.exe
• VsTskMgr.exe

It tries to delete the following services related to security products:

• KPfwSvc
• KWhatchsvc
• McAfee Framework
• McShield
• Norton Antivirus Server
• Symantec Antivirus
• Symantec Antivirus Definition Watcher
• Symantec Antivirus Drivers Services

It modifies the following registry entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Advanced\Folder\Hidden\"SHOWALL" = "2"

It deletes the following registry subkeys to prevent the compromised computer restarting in Safe Mode:

• HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Minimal\{4D36E967-E325-11CE-BFC1-08002BE10318}
• HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\SafeBoot\Network\{4D36E967-E325-11CE-BFC1-08002BE10318}
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Minimal\{4D36E967-E325-11CE-BFC1-08002BE10318}
• HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SafeBoot\Network\{4D36E967-E325-11CE-BFC1-08002BE10318}

Users may then experience any of the following messages while trying to restart the computer in Safe Mode:

• blue-screen
• network problems
• error: "STOP: 0x0000007B"

It runs a hidden Internet Explorer windows to download and install the following malicious files:

• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/[REMOVED]
• [http://]m.d5x8.com/dd/10.[REMOVED]

The files are downloaded and saved as the following files:

• C:\Documents and Settings\All Users\1.pif
• C:\Documents and Settings\All Users\2.pif
• C:\Documents and Settings\All Users\3.pif
• C:\Documents and Settings\All Users\4.pif
• C:\Documents and Settings\All Users\5.pif
• C:\Documents and Settings\All Users\6.pif
• C:\Documents and Settings\All Users\7.pif
• C:\Documents and Settings\All Users\8.pif
• C:\Documents and Settings\All Users\9.pif
• C:\Documents and Settings\All Users\10.pif
• C:\Documents and Settings\All Users\ms.pif

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.

Summary