The new version of the Klez worm has been found from various
parts of Asia on April 17th, 2002. A week after its discovery
Klez.H is still globally spread. This worm, like its previous
versions sends e-mail messages with randomly named attachments
and subject fields.
The Klez.H variant it quite close to Klez.E, F and G worm
variants. The descripions of Klez.E, F and G variants can be
found here:
F-Secure Virus Research Team found the following differences in
Klez.H variant comparing to its previous versions:
1. There's no payload routine.
2. The .PDF extension was added to the list of extensions that
the worm uses to make a double-extension name for its file.
3. The worm sometimes uses social engineering approach in its
spreading and sends the following message with its own file
attached:
Subject:
Worm Klez.E immunity
Body:
Klez.E is the most common world-wide spreading worm.It's very
dangerous by corrupting your files.
Because of its very smart stealth and anti-anti-virus
technic,most common AV software can't detect or clean it.
We developed this free immunity tool to defeat the malicious
virus.
You only need to run this tool once,and then Klez will never
come into your PC.
NOTE: Because this tool acts as a fake Klez to fool the real
worm,some AV monitor maybe cry when you run it.
If so,Ignore the warning,and select 'continue'.
If you have any question,please mail to me.
The 'mail to me' is represented as a link to the sender's e-mail
address. Note that this address is not always the real sender's
address.
4. The worm contains a new text message from its author. This
text is never displayed:
Win32 Klez V2.01 & Win32 Foroux V1.0
Copyright 2002,made in Asia
About Klez V2.01:
1,Main mission is to release the new baby PE virus,Win32 Foroux
2,No significant change.No bug fixed.No any payload.
About Win32 Foroux (plz keep the name,thanx)
1,Full compatible Win32 PE virus on Win9X/2K/NT/XP'
2,With very interesting feature.Check it!
3,No any payload.No any optimization'
4,Not bug free,because of a hurry work.No more than three weeks
from having such idea to accomplishing coding and testing'
5. The worm drops the new Elkern virus variant. Unlike the previous Klez
versions, Klez.H puts the virus dropper into \Program Files\ folder
with a random name and activates it.
6. The worm added 2 more names to the list of anti-virus
companies that it previously had. These new names are:
Trendmicro
Kaspersky
These names are used by the worm to compose messages when it
sends itself as a virus removal tool from anti-virus companies.
7. It was also noticed that latest Klez variants including Klez.H
can send out user's files with its message. The worm can randomly
pick up a file with one of the following extensions and attach it
to its infected message:
