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  3. W32.Blebla.Worm

W32.Blebla.Worm

Risk Level 1: Very Low

Discovered:
November 15, 2000
Updated:
February 13, 2007 11:32:37 AM
Also Known As:
Romeo and Juliet, W32/Verona, Troj Blebla.A
Type:
Worm

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:
  • Romeo&Juliet
  • :))))))
  • hello world
  • !!??!?!?
  • subject
  • ble bla, bee
  • I Love You ;)
  • sorry...
  • 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:
  • 213.25.111.2 memo.gate.pl
  • 194.153.216.60 mail.getin.pl
  • 195.117.152.91 dns.inter-grafix.com.pl
  • 212.244.199.2 gate.paranormix.net.pl
  • 195.116.62.86 madmax.quadsoft.com
  • 195.117.99.98 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.


Recommendations

Symantec Security Response encourages all users and administrators to adhere to the following basic security "best practices":

  • Use a firewall to block all incoming connections from the Internet to services that should not be publicly available. By default, you should deny all incoming connections and only allow services you explicitly want to offer to the outside world.
  • Enforce a password policy. Complex passwords make it difficult to crack password files on compromised computers. This helps to prevent or limit damage when a computer is compromised.
  • Ensure that programs and users of the computer use the lowest level of privileges necessary to complete a task. When prompted for a root or UAC password, ensure that the program asking for administration-level access is a legitimate application.
  • Disable AutoPlay to prevent the automatic launching of executable files on network and removable drives, and disconnect the drives when not required. If write access is not required, enable read-only mode if the option is available.
  • Turn off file sharing if not needed. If file sharing is required, use ACLs and password protection to limit access. Disable anonymous access to shared folders. Grant access only to user accounts with strong passwords to folders that must be shared.
  • Turn off and remove unnecessary services. By default, many operating systems install auxiliary services that are not critical. These services are avenues of attack. If they are removed, threats have less avenues of attack.
  • If a threat exploits one or more network services, disable, or block access to, those services until a patch is applied.
  • Always keep your patch levels up-to-date, especially on computers that host public services and are accessible through the firewall, such as HTTP, FTP, mail, and DNS services.
  • Configure your email server to block or remove email that contains file attachments that are commonly used to spread threats, such as .vbs, .bat, .exe, .pif and .scr files.
  • Isolate compromised computers quickly to prevent threats from spreading further. Perform a forensic analysis and restore the computers using trusted media.
  • Train employees not to open attachments unless they are expecting them. Also, do not execute software that is downloaded from the Internet unless it has been scanned for viruses. Simply visiting a compromised Web site can cause infection if certain browser vulnerabilities are not patched.
  • If Bluetooth is not required for mobile devices, it should be turned off. If you require its use, ensure that the device's visibility is set to "Hidden" so that it cannot be scanned by other Bluetooth devices. If device pairing must be used, ensure that all devices are set to "Unauthorized", requiring authorization for each connection request. Do not accept applications that are unsigned or sent from unknown sources.
  • For further information on the terms used in this document, please refer to the Security Response glossary.
Writeup By: Peter Szor
Summary| Technical Details| Removal

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