Macros: Better Applications or Worse Viruses
At the base, macros are a series of commands, as in MS Excel or MS Word, grouped together for executing oft repeated tasks in an automated sequence.
They are small programs which record a series of commands in an application and when run, they automatically execute expediting the repetitive tasks. In the following paragraphs we will know as to what a macro virus is and what harm macro viruses can do to your computer and ways to deal with macro viruses.
What is a Macro Virus
A macro virus is a series of computer codes written in macro language and embedded in any document, usually of a Microsoft office package, which opens when you open a document. It performs preprogrammed tasks automatically. The predominant ones are word macro virus and excel macro virus. But what is so horrifying about macro viruses is that 75% of all viruses to day are macros and can embed into your computer system and infest all future files or documents you might create. Nevertheless, these are filtered out by popular antivirus programs, but you never know. The major distinctive part of macro viruses is that they infect documents and document templates and not programs.
How Is the Computer Infected With a Macro Virus?
Usually macro viruses are received as attachments in emails and when you download the attachments they unfurl and install on your computer. Irrespective of whether it is Melissa macro virus or for that matter any other office XP macro virus, it launches along with the appropriate Windows office application and propagates. Under specific conditions the virus generates attachments to all documents you mail and spread thus. If your recipient had macros turned on, he had it. The vulnerability to macros comes from the fact that most people don't have the practice of scanning their received documents before they can be downloaded!
Mail clients like Yahoo!, for example, scan all attachments for viruses and warn the recipient. Invariably all attachment are channeled thru scans to prevent trouble. But is it safe to use MS Outlook? Certain malicious attachments execute even when mails are read in preview panel. Just reading the address book can trigger viruses to propagate easily. Some viruses don't depend on Outlook's SMTP engine (mail transfer protocol), and one they own themselves! Most popular virus here is Romeo and Juliet (also called as BleBla.)
How Do I Know My Computer Is Infected With A Macro?
This is especially simple. All you have to do is follow the steps below.
- Launch the program you want to check for macros
- Go to tools menu and choose Macros sub menu
- This opens a dialog box which lists the macros, if there are any
- You can expect infection if you find following names in the list:
- Check_files
- Auto_Open
- PERSONAL.XLS!check_files
- PERSONAL.XLS!auto_open
- In other cases where you have an infected work book (MS Excel) open in the background you may find the following:
- !check_files
- !auto_open
- 6. Alternately you can go to C:\MSOFFICE\EXCEL directory to find if there is a hidden infected file called PERSONAL.XLS. Set all files to visible status to see the file if it exists. However, you will need to check for new types as they macro viruses are generated more frequently than we think.
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