X97M.Booklet.A

SUMMARY

X97M.Booklet.A is a macro virus that infects macros in Microsoft Excel files.

Protection

• Virus Definitions (Intelligent Updater) January 29, 2002

TECHNICAL DETAILS

This macro virus activates when an infected file is opened. It performs the following actions:

1. First, it checks if the user name is "booky". If it is not, it sets the user name to "booky".
2. Next, it saves the infected workbook in the XLStart folder as Booky.xls. This is done so that the virus can infect other workbooks when they are opened.
3. It then sets the status bar to display the text "BookY RuLz Hir...Hehehe"
4. Finally, it searches through the files that are listed in the recently used file list. Each file is checked to see if it is infected already.
   • If it finds an infected file, then it immediately closes the active workbook.
   • If it finds an uninfected file, then it infects that file, saves the active workbook and closes it.

This virus unsuccessfully attempts to be polymorphic and it contains many programming bugs, which may result in corrupting itself to the extent that it does not function any more after several replications.

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. If any files are detected as infected by X97M.Booklet.A, click Repair. Any files that are corrupted and cannot be repaired should be deleted and restored from a clean backup copy.