W32/Mytob.AH Worm

 Virus Information - W32/Mytob.AH Worm:

W32/Mytob.AH is a worm. This worm is a variant of W32/Mytob.A. The worm will infect Windows systems and spreads through email.

The infected mail 'From' address prefix will be any one of the following;

adam, alex, alice, andrew, anna, bill, bob, brenda, brent, brian, claudia, dan, dave, david, debby, fred, george, helen, jack, james, jane, jerry, jim, jimmy, joe, john, jose, julie, kevin, leo, linda, maria, mary, matt, michael, mike, peter, ray, robert, sam, sandra, serg, smith, stan, steve, ted, tom

the suffix after '@' character will be any one of the following domains;

hotmail.com
cia.gov
fbi.gov
yahoo.com
juno.com
msn.com
aol.com

The subject of the infected mail will be any one of the following;

Good Day
hello
Error
Mail Delivery System
Mail Transaction Failed
Server Report
Status

The infected attachment will be any one of the following;

document
body
readme
data
file
test
message
doc
text

with any one of these extensions;

bat, cmd, doc, exe, htm, pif, scr, tmp, txt, zip.

The body of the infected mail will be any one of the following;

Mail transaction failed. Partial message is available.

The message contains Unicode characters and has been sent as a binary attachment.

The message cannot be represented in 7-bit ASCII encoding and has been sent as a binary attachment.

The original message was included as an attachment.

Here are your banks documents

Upon execution of the infected attachment, the worm copies itself as taskgmr.exe in the Windows System folder.

It also drops funny pic.scr and photo album.scr in the root of C: drive.

The worm modifies registry at the following location to load itself during each startup.

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunServices
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run

The worm also blocks access to some of the security related websites.

To propagate itself, the worm scans the files having the following extensions and collects all the available email addresses from the infected system.

adb, asp, dbx, htm, php, pl, sht, tbb, wab

It also collects email addresses from the Temporary Internet Files folder.

The worm attempts to locate SMTP server by appending the following prefixes to the domain names collected from the infected system. On successful SMTP server access it mails itself to the collected email addresses.

mx.
ns.
relay.
mail1.
mxs.
mx1.
smtp.
mail.
gate.