In antivirus lingo, attachments are files added to an outgoing email. In Microsoft email clients, email carrying an attachment will have a paper-clip type icon beside the description. Also in Microsoft email clients, an icon representing the file type will be embedded at the end of the body of the email message. Attachments have become a known harbinger of email worm and trojan infection.
Malware distributors often give the attachment a double extension. Users who do not have proper viewing settings configured in Internet Explorer can be tricked into believing an executable file is a non-executable file type. For more information, see Executable File Extensions.
To avoid email delivered malware, do not open attachments received unexpectedly - even if it is from someone you know. Quite often, email worms spread by sending themselves to recipients listed in the infected user's address book. The same precaution should be taken with links contained in an email message. Do not follow the links in email received unexpectedly. For more information, see Fraudulent Link Scams.
