Trojan:W97M/MaliciousMacro identifies a macro program that has been embedded in a specially-crafted Microsoft Word document. If the user opens the Word file, the macro is automatically run and its payload is executed.
Depending on the settings of your F-Secure security product, it will either automatically delete, quarantine or rename the suspect file, or ask you for a desired action.
More information on the scanning and removal options available in your F-Secure product can be found in the Help Center.
You may also refer to the Knowledge Base on the F-Secure Community site for more information.
Specially-crafted Word documents carrying embedded malicious macro programs are typically distributed as attachments to spam e-mail messages.
In cases of targeted phishing attacks (also known as spear phishing), the e-mail messages are deliberately tailored for a specific organization or user, to increase the chances that the user will accept the attached document as authentic and open it, thereby unintentionally infecting themselves.
The malicious macro code is often designed to automatically run when the Word document is opened. In some cases, the user may be shown a notification message asking them to "allow a macro to run". The user must do so before the macro code can perform its harmful actions.
The actions the malicious macro can take are varied, but usually involve contacting a remote command and control (C&C) server and downloading and/or installing additional files onto the machine.