W32.Polip is a polymorphic virus that infects .exe and .scr files when they are opened or executed on the compromised computer.

Also Known As: Polipos.a [F-Secure], P2P-Worm.Win32.Polip.a [Kaspersky Lab], W32/Polipos [McAfee], W32/Polipos-A [Sophos], PE_POLIP.A [Trend Micro]   Type: Virus Systems Affected: Windows 2000, Windows 95, Windows 98, Windows Me, Windows NT, Windows Server 2003, Windows XP
- Virus Definitions (LiveUpdate™ Plus)

April 23, 2006

- Virus Definitions (LiveUpdate™ Daily)

April 23, 2006

- Virus Definitions (LiveUpdate™ Weekly)

April 24, 2006

- Virus Definitions (Intelligent Updater)

April 23, 2006

Wild

• Number of infections: 50 - 999
• Number of sites: More than 10
• Geographical distribution: Medium
• Threat containment: Easy
• Removal: Difficult

Threat Metrics

Wild:
Low

Damage:
Medium

Distribution:
Medium

Damage

• Payload Trigger: n/a
• Payload: Infects .exe and .scr files and lowers security settings. - Large scale e-mailing: n/a
• Deletes files: n/a
• Modifies files: n/a
• Degrades performance: n/a
• Causes system instability: n/a
• Releases confidential info: n/a
• Compromises security settings: n/a

Distribution

• Subject of email: n/a
• Name of attachment: n/a
• Size of attachment: n/a
• Time stamp of attachment: n/a
• Ports: n/a
• Shared drives: n/a
• Target of infection: Infects .exe and .scr files.

When W32.Polip is installed, it performs the following actions:

1. Infects .scr and .exe files when they are opened or executed on the compromised computer.
2. Hides its presence on the compromised computer by injecting its code into running processes.
3. Attempts to spread by sharing infected files on the Gnutella file sharing network, even if the Gnutella software isn't installed on the compromised computer.
4. Tries to lower security settings by deleting certain files relating to antivirus software.

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.

The following instructions pertain to all current and recent Symantec antivirus products, including the Symantec AntiVirus and Norton AntiVirus product lines.

1. Disable System Restore (Windows Me/XP).
2. Update the virus definitions.
3. Run a full system scan.