F-Secure Virus Descriptions : Updater
Updater is a mass mailing worm that is a Windows PE executable. Its
size is about 12 KB and it is written in Visual Basic (VB6). It packed
by the program UPX. After unpacking its size is 45 KB.
The worm activates from infected email only in case a user clicks on
attached file. The worm then installs itself to the system, runs
spreading routine and payload.
The infected messages have different texts and attached file names,
they are randomly selected by worm while spreading from following
variants:
Subjects are:
Part1 + Part2 + Part3 + Part4
Part1 = "Have you ", "You Should ", "Just ", "Why Not you ", "How to ", "Re: ",
"Fwd : ", " "
Part2 = "Check ", "Check out ", "Watch out ", "Open ", "Look at "
Part3 = "this ", "my ", "For this ", "The "
Part4 = "Picture", "Program", "Patch", "Nude pic", "Report", "Documment",
"Quotation", "Transaction", "Bank Account", "WTC Tragedy", "Osama Vs Bush"
"Account", "Private Pic"
Examples:
You Should Look at this Osama Vs Bush
Fwd : Check my Patch
Atach filenames are:
"Setup.EXE", "install.exe", "Readme.exe", "Files.exe", "Picture.exe"
"Quotation.Doc.exe", "Letter.Doc.exe", "Picture.jpg.exe"
Body:
Hi:
This is the file you ask for, Please save it to disk and open this file,
it's very important.
When the worm is executed, it copies itself to the C:\WINDOWS\
directory with the UPDATE.EXE name and registers that file in system
registry auto-run key:
HKLM\Software\Microsoft\Windows\CurrentVersion\Run
Update = C:\WINDOWS\Update.exe
The worm then displays a fake error message:
Cannot Open files : It does not appear to be a valid archive
if you Downloaded this file , try downloading the file again.
[ OK ]
Next the worm creates the file
C:\WINDOWS\STARTM~1\PROGRAMS\STARTUP\Update.vbs. This script file
starts automatically after rebooting system under Windows 9x/ME. It
looks for files on all drives with expansions: EXE, DOC, TXT. It
creates script copies with the same names + expantion: ".vbs" For
example:
MPLAYER.EXE.vbs
NOTEPAD.EXE.vbs
This script file contains the strings:
I-WORM.IMELDA.B
The worm changes a volume label on disk C: the the IMELDA.
The worm also copies itself to the C:\WINDOWS\ directory with one of
this names:
"Setup.EXE", "install.exe", "Readme.exe", "Files.exe",
"Picture.exe" "Quotation.Doc.exe", "Letter.Doc.exe", "Picture.jpg.exe"
[Analysis: Kaspersky Labs, December 7th, 2001.]
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