W32.Anset.Worm

SUMMARY

W32.Anset.Worm is a Internet worm written in Delphi. It arrives as email with the attachment Ants3set.exe. This worm spreads by sending itself to email addresses found in the Microsoft Outlook address book. It is disguised as a freeware Trojan horse scanner known as ANTS.

Protection

• Virus Definitions (Intelligent Updater) October 25, 2001

Threat Assessment

Wild

• Wild Level: Low
• Number of Infections: 0 - 49
• Number of Sites: 0 - 2
• Geographical Distribution: Low
• Threat Containment: Easy
• Removal: Easy

Damage

• Damage Level: Low
• Payload Trigger: Execution of the attachment
• Large Scale E-mailing: Attempts to send itself to email addresses in the Outlook address book.

Distribution

• Distribution Level: High
• Subject of Email: ANTS Version 3.0
• Name of Attachment: Ants3set.exe
• Size of Attachment: 179,712 bytes

TECHNICAL DETAILS

When W32.Anset.Worm is executed, it does the following:

It makes a copy of itself in the Windows folder using a random file name.

It sends itself to email addresses in the Microsoft Outlook address book. The email message has the following characteristics:

Subject: ANTS Version 3.0
Attachment: Ants3set.exe
Message:
Hi, Anhängend die neue Version 3.0 von ANTS, dem bislang einzigartigen kostenlosen Trojanerscanner. Zum installieren einfach die angefügte Datei ausführen.
Attached you will find the brand new Version 3.0 of ANTS, the unique freeware trojan scanner. To install ANTS simply run the attached setup file.

Recommendations

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

• Turn off and remove unneeded services. By default, many operating systems install auxiliary services that are not critical, such as an FTP server, telnet, and a Web server. These services are avenues of attack. If they are removed, blended threats have less avenues of attack and you have fewer services to maintain through patch updates.
• If a blended 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 (for example, all Windows-based computers should have the current Service Pack installed.). Additionally, please apply any security updates that are mentioned in this writeup, in trusted Security Bulletins, or on vendor Web sites.
• 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.
• Configure your email server to block or remove email that contains file attachments that are commonly used to spread viruses, such as .vbs, .bat, .exe, .pif and .scr files.
• Isolate infected computers quickly to prevent further compromising your organization. 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.

REMOVAL

1. Run LiveUpdate to make sure that you have the most recent virus definitions.
2. Start Norton AntiVirus (NAV), and make sure that NAV is configured to scan all files. For instructions on how to do this, read the document How to configure Norton AntiVirus to scan all files.
3. Run a full system scan.
4. Delete all files that are detected as W32.Anset.Worm.