Do Not Open Unexpected Email Attachments From Known or Unknown Sources

Do Not Open Unexpected Email Attachments From Known or Unknown Sources

Do not open unexpected email attachments from known or unknown sources. A malicious e-mail attachment is one of the oldest, most effective, and easiest methods of infecting a computer. Always check the file extension of an e-mail attachment, because cyber-criminals can disguise a malicious attachment as a Microsoft Word document, PDF document, or other legitimate documents. Attachments ending with ".zip" or ".rar" are compressed files that should not be open if the sender is unknown to you, or you were not expecting the email message.

Here are the extensions of some e-mail attachments that you should never open regardless of where they came from, even if you were expecting them or not:

Extension --- Description

  • .JAR -- Java archive
  • .SCR -- Windows Screen Saver
  • .BAT -- Batch File Windows
  • .CMD -- Command Script Windows
  • .COM -- Command File Windows
  • .COMMAND -- Terminal Command Mac OS
  • .CSH -- C Shell Script Mac OS, Linux
  • .EXE -- Executable Windows
  • .JSE -- JScript Encoded File Windows
  • .KSH -- Unix Korn Shell Script Linux
  • .LNK -- File Shortcut Windows
  • .MSC -- Microsoft Common Console Document Windows
  • .MSI -- Windows Installer Package Windows
  • .MSP -- Windows Installer Patch Windows
  • .MST -- Windows Installer Setup Transform File Windows
  • .OSX -- Executable Mac OS
  • .OUT -- Executable Linux
  • .PIF -- Program Information File Windows
  • .PS1 -- Windows PowerShell Cmdlet Windows
  • .REG -- Registry Data File Windows
  • .RGS -- Registry Script Windows
  • .RUN -- Executable Linux
  • .SHB -- Windows Document Shortcut Windows
  • .SHS -- Shell Scrap Object Windows
  • .VB -- VBScript File Windows
  • .VBE -- VBScript Encoded Script Windows
  • .VBS -- VBScript File Windows
  • .VBSCRIPT -- Visual Basic Script Windows
  • .WS -- Windows Script Windows
  • .WSF -- Windows Script Windows
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Note: Some of the information in samples on this website may have been impersonated or spoofed.
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Comments (Total: 3)

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  • September 5, 2016 at 8:39 AM by info

    Here is an email with a malicious attachment:

    "From: Octavio Scott <>

    Subject: Credit card receipt

    Date: Mon 9/05/16 7:29 AM

    Attachment: (11.3 KB)

    Dear info,

    We are sending you the credit card receipt from yesterday. Please match the card number and amount.

    Sincerely yours,

    Octavio Scott

    Account manager"

  • July 5, 2016 at 7:48 PM by info

    Look out for the following malicious email message:

    Subject: Scanned image

    Attachment: 05-07-2016_746086513.docm

    Image data has been attached to this email.

  • June 27, 2016 at 11:14 AM by info

    Here is another fake email message attempting to trick the recipients into open the malicious zip file:

    From: Pat Welch (Welch.5462@thegarage .co)

    Sent: Mon 6/27/16 9:01 AM

    Attachments: (8.3 KB)

    Dear info,

    The document you requested is attached.

    Best regards

    Pat Welch

    Key Account Manager

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Do Not Open Unexpected Email Attachments From Known or Unknown Sources