You are prompted to accept or reject certain Windows Messenger files in Windows XP Service Pack 2 (883261)

SYMPTOMS

When you are running Microsoft Windows XP Service Pack 2 (SP2), and you receive a Windows Messenger file from another computer, you may be prompted to either accept or reject the file.

If you accept the file, you may receive the following warning message:

Warning: Some files may contain harmful viruses or scripts. Here's how to protect yourself against viruses:

- Be sure you know who is sending you this file. More importantly, be sure you know what this file contains before you accept it, as many viruses pretend to come from someone you know.

- Run anti-virus software on all transferred files before you open them to ensure they aren't infected.

- Make sure your anti-virus software is up-to-date. Go to your anti-virus company's Web site or call them to get more information.

If you have any doubts about this file, click Cancel. Then ask the sender what the file contains, and make sure they really sent it.

CAUSE

Windows XP SP2 prompts you about a Windows Messenger file if one of the following conditions is true:

The sender of the file is not included in the Windows Messenger contacts list.
Windows Messenger considers the file potentially unsafe.

To safeguard you computer from potential viruses that spread through instant messaging and file transfer, you receive the message that is mentioned in the "Symptoms" section when you try to open the following file types:

Microsoft Office files, such as .doc, .ppt, or .xls files.
Other program files, such as .zip, .wpd, or .pdf files.
Files with the .exe, .cmd, .wsh, .bat, .vb, .vbs; .pif, .scr, .scf extensions.

You may also receive this message if you open a file that contains software code or scripts, including macros, executables, and JavaScript.

MORE INFORMATION

Windows XP SP2 offers a set of security technologies that improves the ability of Windows XP-based computers to withstand malicious attacks from viruses and worms.

The following file types are generally considered safe, and you can accept files that have these extensions from someone who is not listed in the Windows Messenger contacts list:

.txt (Text)
.gif (Graphic Interchange Format)
.jpg (Joint Photographic Experts Group format)

We recommend that you accept only files that you can save to your hard disk. Use an antivirus program to scan the files before you open them.

REFERENCES

For additional information about file types that are considered potentially unsafe, click the following article number to view the article in the Microsoft Knowledge Base:

291369 Information about the unsafe file list in Internet Explorer 6