The W32.Blebla.Worm was first reported in Poland. The worm arrives as an email message that has an HTML body and two attachments named Myjuliet.chm and Myromeo.exe. The subject of the email is selected randomly from the following set:
- hello world
- ble bla, bee
- I Love You ;)
- Hey you !
- Matrix has you...
- my picture
- from shake-beer
This worm functions only under Windows 95, Windows 98, and Windows 2000 systems that have not been updated with the latest vulnerability updates from Microsoft. It does not run under Windows NT. The HTML component saves the attachments in the \Windows\Temp folder, and then executes the Myjuliet.chm (compiled HTML) file. That file then launches the Myromeo.exe file, which is the mass-mailer component of the worm. When executed, the Myromeo.exe file looks for the running copy of HH.exe (that is associated with .chm files) and tries to stop it in order to hide its activity. In the meantime, a task with Romeo&Juliet as its name can be seen in the task list.
Next, the virus queries the Microsoft Outlook address book, and tries to propagate itself using six different mail servers that are located in Poland. Several of these servers are not currently available, and others are protected from nonauthenticated email traffic. However the worm might be able to spread inside Poland by the users of these particular mail servers:
- 184.108.40.206 memo.gate.pl
- 220.127.116.11 mail.getin.pl
- 18.104.22.168 dns.inter-grafix.com.pl
- 22.214.171.124 gate.paranormix.net.pl
- 126.96.36.199 madmax.quadsoft.com
- 188.8.131.52 promail.pl
The virus has its own email engine. It attempts to connect to one of the these servers and tries to send its email message with MIME-encoded attachments. The size of the mailer component is 29,184 bytes. It is written in Borland Delphi, but the code is packed using the popular UPX packer. The original unpacked code would be about 60 KB.
Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":