Summary

Mimail.E worm was found on 1st 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

Additional Details

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

1. The Mimail.E 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:

[HKLM\Software\Microsoft\Windows\CurrentVersion\Run] "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:

spews.org spamhaus.org spamcop.net www.spews.org www.spamhaus.org www.spamcop.net
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 .E 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 1st, 2003 in the following updates:

[FSAV_Database_Version]
Version=2003-11-01_02

Technical Details: Alexey Podrezov, November 3rd, 2003;