Threat Description

Mimail.H

Details

Aliases: Mimail.H, W32/Mimail.H@mm, I-Worm.Mimail.h
Category: Malware
Type: Email-Worm
Platform: W32

Summary



Mimail.H worm was found on 2nd of November, 2003. It is a close variant of Mimail.C worm. The description of Mimail.C worm variant can be found here:

http://www.europe.f-secure.com/v-descs/mimail_c.shtml



Removal



Automatic Disinfection

Allow F-Secure Anti-Virus to disinfect the relevant files.

For more general information on disinfection, please see Removal Instructions.



Technical Details



The Mimail.H worm is a minor variant of Mimail.C worm. The differences between these 2 versions are as follows:

1. The Mimail.H worm's file is 10784 bytes long, compressed with UPX file compressor, the unpacked file's size is 23072 bytes.

2. The worm installs itself to Windows folder as CNFRM33.EXE file and creates a startup key in the Registry:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run]
 "Cn323" = "%windir\cnfrm33.exe"
 

where %windir% is a Windows directory name.

3. The worm performs a DoS (Denial of Service) attack on the following sites:

spamhaus.org
 spews.org
 www.spamhaus.org
 www.spews.org
 

4. The worm spreads itself in the following message:

From: john@<domain of the recipient>

Subject: don't be late!     <some random characters>

Body:
 Will meet tonight as we agreed, because on Wednesday I don't think I'll make it,
 so don't be late. And yes, by the way here is the file you asked for.
 It's all written there. See you.
<some random characters>

Attachment: readnow.zip
 

The attachment is a ZIP archive that contains the worm's executable file with READNOW.DOC.SCR name.

5. The .H worm variant doesn't have the spying functionality that was present in the .C worm variant.



Detection


Detection in F-Secure Anti-Virus was published on November 3rd, 2003 in the following updates:
Detection Type: PC
Database: 2003-11-03_01



Description Created: Alexey Podrezov, November 3rd, 2003


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