INIT-9403

SUMMARY

INIT-9403 is a malicious virus discovered in Italy in March 1994. INIT-9403 attempts to destroy disks. However, it only infects and spreads on Italian operating systems.

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

Distribution

• Distribution Level: Low

TECHNICAL DETAILS

INIT-9403 infects the Finder and selected applications. When an infected application is run, an invisible file named "Preferenze" is created. Under System 7, the file is placed in the Extensions folder; under System 6, it is placed in the System folder. The invisible file, which contains viral code, is executed automatically and infects the Finder the next time the infected computer is started. Then, on the following startup, the infected Finder deletes the invisible file and begins infecting applications. INIT-9403 is triggered at a time that is derived from the number of infections and the system time. When triggered, INIT-9403 attempts to destroy the startup volume by writing data over its entire length. In addition, INIT-9403 attempts to overwrite the disk information (volume information sectors and volume bitmap) on each connected hard drive larger than 16 MB.

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.