W32.SillyFDC.BDP

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Discovered: March 10, 2011
Updated: March 11, 2011 8:31:31 AM
Also Known As: Mal/Rorpian-B [Sophos]
Type: Worm
Infection Length: 63,488 bytes
Systems Affected: Windows

W32.SillyFDC.BDP is a worm that spreads through removable drives and downloads other files onto the compromised computer.

Antivirus Protection Dates

  • Initial Rapid Release version March 10, 2011 revision 036
  • Latest Rapid Release version April 21, 2018 revision 004
  • Initial Daily Certified version March 10, 2011 revision 038
  • Latest Daily Certified version April 22, 2018 revision 007
  • Initial Weekly Certified release date March 16, 2011

Click here for a more detailed description of Rapid Release and Daily Certified virus definitions.

Writeup By: Masaki Suenaga, Takashi Katsuki, and Stephen Doherty

Discovered: March 10, 2011
Updated: March 11, 2011 8:31:31 AM
Also Known As: Mal/Rorpian-B [Sophos]
Type: Worm
Infection Length: 63,488 bytes
Systems Affected: Windows

When executed, the Trojan copies itself as the following file:
%Temp%\srv[THREE RANDOM CHARACTERS].tmp

It then creates the following file:
%Temp%\srv[THREE RANDOM CHARACTERS].ini

It then creates the following registry entries to register itself as a system service:

  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"DisplayName" = "srv7CC"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"ErrorControl" = "1"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"ImagePath" = "%systemroot%\system32\svchost.exe -k netsvcs"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"ObjectName" = "LocalSystem"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"Start" = "2"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\"Type" = "32"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\Security\"Security" = "[BINARY DATA]"
  • HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\srv7CC\parameters\"servicedll" = "\\?\globalroot\Device\HarddiskVolume1\Documents and Settings\[CURRENT USER]\Local Settings\Temp\srv7CC.tmp"

The service has the following characteristics:
Startup Type: Automatic
Image Path: %systemroot%\system32\svchost.exe -k netsvcs
Display Name: srv7CC

It then creates the following registry entries to alter Internet Explorer settings:
  • HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\"ProxyEnable" = "0"
  • HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections\"DefaultConnectionSettings" = "[BINARY DATA]"
  • HKEY_USERS\.DEFAULT\Software\Microsoft\Windows\CurrentVersion\Internet Settings\Connections\"SavedLegacySettings" = "[BINARY DATA]"

It then modifies the following registry entry:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\SvcHost\"netsvcs" = "srv7CC,6to4,AppMgmt,AudioSrv,Browser,CryptSvc,DMServer,DHCP,ERSvc,EventSystem,FastUserSwitchingCompatibility,HidServ,Ias,Iprip,Irmon,LanmanServer,LanmanWorkstation,Messenger,Netman,Nla,Ntmssvc,NWCWorkstation,Nwsapagent,Rasauto,Rasman,Remoteaccess,Schedule,Seclogon,SENS,Sharedaccess,SRService,Tapisrv,Themes,TrkWks,W32Time,WZCSVC,Wmi,WmdmPmSp,winmgmt,wscsvc,xmlprov,BITS,wuauserv,ShellHWDetection,helpsvc,WmdmPmSN"

The threat then injects itself into one of the following processes:
  • spooler.exe
  • svchost.exe


Note: If the spooler.exe process is not running, the threat will attempt to start it.

The worm connects to the following URLs in order to download other threats:
  • [http://][IP ADDRESS]/sknoc[REMOVED]
  • [http://][IP ADDRESS]/service/lister[REMOVED]
  • [http://][IP ADDRESS]/service/scripts/files/af[REMOVED][NUMBER].dll
  • [http://][IP ADDRESS]/s[REMOVED]
  • [http://][IP ADDRESS]/d[REMOVED]
  • [http://][IP ADDRESS]/e[REMOVED]


Note: [IP ADDRESS] is a variable for one of the following IP Addresses:
  • 109.235.49.103
  • 77.79.9.191
  • 178.32.189.105
  • 188.138.48.178
  • 94.75.193.21
  • 94.75.193.20
  • 195.14.112.138
  • 86.55.210.72
  • 86.55.210.55

Note: Known threats downloaded by the worm at this time include W32.Tidserv .

The threat sets up its own DHCP server using UDP ports 67 and 68 and then listens for other computers on the same network attempting to renew their IP addresses. The threat then sends fake DHCP offer packets in an attempt to hijack the DNS configuration of the other computer.

The worm attempts to spread by exploiting the following vulnerabilities:


It also copies itself to network shares and removable drives as the following files:


It also creates the following file so that it executes whenever the drive is used on another computer:
%DriveLetter%\Autorun.inf

If the worm finds that the newly compromised computer is using the poisoned DNS IP it is sending through DHCP, it resets it to the following Google Public DNS IP address:
8.8.8.8

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.

Writeup By: Masaki Suenaga, Takashi Katsuki, and Stephen Doherty

Discovered: March 10, 2011
Updated: March 11, 2011 8:31:31 AM
Also Known As: Mal/Rorpian-B [Sophos]
Type: Worm
Infection Length: 63,488 bytes
Systems Affected: Windows

You may have arrived at this page either because you have been alerted by your Symantec product about this risk, or you are concerned that your computer has been affected by this risk.

Before proceeding further we recommend that you run a full system scan . If that does not resolve the problem you can try one of the options available below.



FOR NORTON USERS
If you are a Norton product user, we recommend you try the following resources to remove this risk.

Removal Tool


If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .


How to reduce the risk of infection
The following resources provide further information and best practices to help reduce the risk of infection.


FOR BUSINESS USERS
If you are a Symantec business product user, we recommend you try the following resources to remove this risk.

Identifying and submitting suspect files
Submitting suspicious files to Symantec allows us to ensure that our protection capabilities keep up with the ever-changing threat landscape. Submitted files are analyzed by Symantec Security Response and, where necessary, updated definitions are immediately distributed through LiveUpdate™ to all Symantec end points. This ensures that other computers nearby are protected from attack. The following resources may help in identifying suspicious files for submission to Symantec.


Removal Tool

If you have an infected Windows system file, you may need to replace them using from the Windows installation CD .


How to reduce the risk of infection
The following resource provides further information and best practices to help reduce the risk of infection.
Protecting your business network



MANUAL REMOVAL
The following instructions pertain to all current Symantec antivirus products.

1. Performing a full system scan
How to run a full system scan using your Symantec product


2. Restoring settings in the registry
Many risks make modifications to the registry, which could impact the functionality or performance of the compromised computer. While many of these modifications can be restored through various Windows components, it may be necessary to edit the registry. See in the Technical Details of this writeup for information about which registry keys were created or modified. Delete registry subkeys and entries created by the risk and return all modified registry entries to their previous values.

Writeup By: Masaki Suenaga, Takashi Katsuki, and Stephen Doherty