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Category: Malware

Type: Email-Worm

Aliases: Mimail.F, W32/Mimail.F@mm, I-Worm.Mimail.f


Mimail.F 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:



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Technical Details

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

1. The Mimail.F 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 CNFRM.EXE file and creates a startup key in the Registry:

"Cnfrm32" = "%windir\cnfrm.exe"

where %windir% is a Windows directory name.

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


4. The worm spreads itself in the following message:

 john@[domain of the recipient]
 don't be late!

 [some random characters]
 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:

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

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