W32.Sircam.Worm@mm

Damage:

• When the Virus is triggered:
  • 1) October 16th, or some attached file contents, triggers file deletion payload.
  • 2) If the file deletion occured, or after 8000 executions, triggers the space filler payload.
• What the Virus does:
  • Large scale e-mailing: The worm appends a random document from the infected PC to itself and sends this new file via email
  • Deletes files: 1 in 20 chance of deleting all files and directories on C:. Only occurs on systems where the date is October 16 and which are using D/M/Y as the date format. Always occurs if attached file contains "FS2" not followed by "sc".
  • Degrades performance: 1 in 50 chance of filling all remaining space on the C: drive by adding text to the file c:\recycled\sircam.sys
  • Releases confidential info: It will export a random document from the hard drive by appending it to the body of the worm

Distribution:

• Subject of email: Random subject - the filename of the attachment
• Name of attachment: A file from the sender's computer with the extension .bat, .com, .lnk, or .pif added to it.
• Size of attachment: at least 134kb long
• Shared drives: searchs for shared drives and copies itself to those it finds

Description:

This worm arrives as an email message with the following content:

Subject: The subject of the email will be random, and will be the same as the file name of the email attachment.
Attachment: The attachment is a file taken from the sender's computer and will have the extension .bat, .com, .lnk or .pif added to it.
Message: The message body will be semi-random, but will always contain one of the following two lines (either English or Spanish) as the first and last sentences of the message.

Spanish Version:
First line: Hola como estas ?
Last line: Nos vemos pronto, gracias.

English Version:
First line: Hi! How are you?
Last line: See you later. Thanks

Between these two sentences, some of the following text may appear:

Spanish Version:
Te mando este archivo para que me des tu punto de vista
Espero me puedas ayudar con el archivo que te mando
Espero te guste este archivo que te mando
Este es el archivo con la informaci=n que me pediste

English Version:
I send you this file in order to have your advice
I hope you can help me with this file that I send
I hope you like the file that I sendo you
This is the file with the information that you ask for

Actions When Run:

When run, the worm performs the following actions:

1. It creates copies of itself as %TEMP%\<File name> and C:\Recycled\<file name>, which contain the attached document. This document is then run using the program registered to handle the specific file type. For example, if it is saved as a file with the .doc extension, it will run using Microsoft Word or Wordpad. A file with the .xls extension will open in Excel, and one with the .zip extension will open in your default zip program, such as WinZip.

NOTE: The term %TEMP% is the Temp variable, and means that the worm will save itself to the Windows Temp folder, whatever its location. The default is C:\Windows\Temp.

2. It copies itself to C:\Recycled\Sirc32.exe and %System%\Scam32.exe.

NOTE: %System% is also a variable. The worm will locate the \System folder (by default this is C:\Windows\System) and copy itself to that location.

3. It adds the value

Driver32=%System%\scam32.exe

to the following registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\
Microsoft\Windows\CurrentVersion\RunServices

4. It creates the following registry key:

HKEY_LOCAL_MACHINE\Software\SirCam

with the following values:
• FB1B - Stores the file name of the worm as stored in the Recycled directory.
• FB1BA - Stores the SMTP IP address.
• FB1BB - Stores the email address of the sender.
• FC0 - Stores the number of times the worm has executed.
• FC1 - Stores what appears to be the version number of the worm.
• FD1 - Stores the file name of worm that has been executed, without the suffix.
  
5. The (Default) value of the registry key

HKEY_CLASSES_ROOT\exefile\shell\open\command

is set to

C:\recycled\sirc32.exe "%1" %*"

This enables the worm to execute itself any time that an .exe file is run.

6. The worm is network aware, and it will enumerate the network resources to infect shared systems. If any are found, it will do the following:
• Attempt to copy itself to <Computer>\Recycled\Sirc32.exe
• Add the line "@win \recycled\sirc32.exe" to the file <Computer>\Autoexec.bat
• Copy <Computer>\Windows\Rundll32.exe to <Computer>\Windows\Run32.exe
• Replace <Computer>\Windows\rundll32.exe with C:\Recycled\Sirc32.exe
  
7. There is a 1 in 33 chance that the following actions will occur:
• The worm copies itself from C:\Recycled\Sirc32.exe to %Windows%\Scmx32.exe
• The worm copies itself as "Microsoft Internet Office.exe" to the folder referred to by the registry key:
  
  HKEY_CURRENT_USER\Software\Microsoft\
  Windows\CurrentVersion\Explorer\
  Shell Folders\Startup
  
8. There is a 1 in 20 chance that on October 16th of any year, the worm will recursively delete all files and folders on the C drive.
This payload functions only on computers which use the date format D/M/Y (as opposed to M/D/Y or similar formats).

Additionally, the payload will always activate immediately, regardless of date and date format, if the file attached to the worm contains the sequence "FA2" without the letters "sc" following immediately.

9. If this payload activates, the file C:\Recycled\Sircam.sys is created and filled with text until there is no remaining disk space. The text is one of two strings:
• [SirCam_2rp_Ein_NoC_Rma_CuiTzeO_MicH_MeX]
  or
• [SirCam Version 1.0 Copyright ¬ 2000 2rP Made in / Hecho en - Cuitzeo, Michoacan Mexico]
  
10. The worm contains its own SMTP engine which is used for the email routine. It obtains email addresses through two different methods:

• It searches the folders that are referred to by the registry keys
  
  HKEY_CURRENT_USER\Software\Microsoft\
  Windows\CurrentVersion\Explorer\
  Shell Folders\Cache
  
  and
  
  HKEY_CURRENT_USER\Software\Microsoft\
  Windows\CurrentVersion\Explorer\
  Shell Folders\Personal
  
  for sho*., get*., hot*., *.htm files, and copies email addresses from there into the file %system%\sc?1.dll
  
  where ? is a different letter for each location, as follows:
  
  • scy1.dll: addresses from %cache%\sho*., hot*., get*.
  • sch1.dll: addresses from %personal%\sho*., hot*., get*.
  • sci1.dll: addresses from %cache%\*.htm
  • sct1.dll: addresses from %personal%\*.htm
    
• It searches %system% and all subfolders for *.wab (all Windows Address Books) and copies addresses from there into %system%\scw1.dll.
  
11. It searches the folders referred to by the registry keys:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Shell Folders\Personal

and

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Shell Folders\Desktop

for files of type .doc, .xls, and .zip, and stores the filenames in %system%\scd.dll. One of these files will be appended to the worm's original executable and this new file will be sent as the email attachment.

The From: email address and mail server are taken from the registry. If no email account exists, then the current user name will be prepended to "prodigy.net.mx", eg if the current user logged on as JSmith, then the address will be "jsmith@prodigy.net.mx". Then the worm will attempt to connect to a mail server. This will be either the mail server taken from the registry, or one of

• prodigy.net.mx
• goeke.net
• enlace.net
• dobleclick.com.mx

The language used for the mail depends on the language used by the sender. If the sender uses Spanish, then the mail will be in Spanish, otherwise it will be in English. The attachment is chosen randomly from the list of files in the scd.dll.

Removal Instructions:

SARC has created a tool to remove this worm.

CAUTION:

• In some cases, if you have had NAV quarantine or delete infected files, you will not be able to run .exe files, however you will still be able to run the removal tool.
• If you are using Windows Me, and a copy of the worm is detected in the _Restore folder when running the tool, the tool cannot remove it from that folder, as it is protected by Windows. See the document Cannot repair, quarantine, or delete a virus found in the _RESTORE folder, and then run the tool again.

Manual Removal:

If for any reason you cannot use or obtain the W32.Sircam.Worm@mm removal tool, you must remove this worm manually. To do this, you must:

• Undo the change that it made to the registry key HKEY_CLASSES_ROOT\exefile\shell\open\command
• Delete any files detected as W32.Sircam.Worm@mm.
• Use Windows Explorer to remove Sircam.sys (if it exists) from the Windows Recycle Bin.
• Remove the entry (if it exists) that the worm made to the file Autoexec.bat, . (This will only be present if the worm has spread across a network.)
• If the file \Windows\Run32.exe exists, rename it back to \Windows\Rundll32.exe

1. Do one of the following, depending on which operating system you are running:
• Windows 95/98 users: Click Start, point to Programs, and click MS-DOS Prompt.
• Windows ME users: Click Start, point to Programs, point to Accessories, and then click MS-DOS Prompt.
• Windows NT/2000 users:
  1. Click Start, and click Run.
  2. Click Browse, and browse to the \Winnt folder.
  3. Double-click the Command.com file, and then click OK.
  
2. Type the following and then press Enter:

copy regedit.exe regedit.com

3. Type the following and then press Enter:

start regedit.com

1. Navigate to and select the following key:

HKEY_CLASSES_ROOT\exefile\shell\open\command

CAUTION: The HKEY_CLASSES_ROOT key contains many subkey entries that refer to other file extensions. One of these file extensions is .exe. Changing this extension can prevent any files ending with an .exe extension from running. Make sure you browse all the way along this path until you reach the \command subkey.
Do not modify the HKEY_CLASSES_ROOT\.exe key.
Do modify the HKEY_CLASSES_ROOT\exefile\shell\open\command subkey that is shown in the following figure:


<<=== NOTE: This is the key that you need to modify.


2. Double-click the (Default) value in the right pane.
3. Delete the current value data, and then type: "%1" %* (That is, type the following characters: quote-percent-one-quote-space-percent-asterisk.)

NOTE: The Registry Editor will automatically enclose the value within quotation marks. When you click OK, the (Default) value should look exactly like this: ""%1" %*"

4. Make sure you completely delete all value data in the command key prior to typing the correct data. If a space is left accidentally at the beginning of the entry, any attempt to run program files will result in the error message, "Windows cannot find .exe." or "Cannot locate C:\ <path and file name>."
5. Navigate to and select the following key:

HKEY_LOCAL_MACHINE\Software\SirCam

CAUTION: Make sure that you go all the way down to the SirCam key, and that it is selected. It will look similar to the following figure:



6. With the SirCam key selected, press Delete and then click Yes to confirm.. This will delete the key and all of its subkeys. Since this key was created by the worm it can be safely deleted.
7. Navigate to and select the following key:

HKEY_LOCAL_MACHINE\Software\
Microsoft\Windows\CurrentVersion\RunServices

8. In the right pane, look for and select the value

Driver32.

9. Press Delete, and then click Yes to confirm.

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and run a full system scan, making sure that NAV is set to scan all files.
3. Delete any files detected as W32.Sircam.Worm@mm.

NOTE: If you are using Windows Me, and a copy of the worm is detected in the _Restore folder, NAV cannot remove it from that folder, as it is protected by Windows. See the document Cannot repair, quarantine, or delete a virus found in the _RESTORE folder.

1. Click Start, and click Run.
2. Type the following, and then click OK.

edit c:\autoexec.bat

The MS-DOS Editor opens.

3. Remove the line "@win \recycled\sirc32.exe" if it is present.
4. Click File and then click Save.
5. Exit the MS-DOS Editor

1. Click Start, point to Find or Search, and then click Files or Folders.
2. Make sure that "Look in" is set to (C:) and that Include subfolders is checked.
3. In the "Named" or "Search for..." box, type--or copy and paste--the following file names:

run32.exe

4. Click Find Now or Search Now.
5. Right-click the Run32.exe file and then click Rename.
6. Rename it to:

RUNDLL32.exe

7. Press Enter.

Additional information:

Configure Windows for maximum protection
Because this virus spreads by using shared folders on networked computers, to ensure that the virus does not reinfect the computer after it has been removed, Symantec suggests sharing with read-only access or using password protection. For instructions on how to do this, see your Windows documentation or the document How to configure shared Windows folders for maximum network protection.