If you downloaded it from the Internet or LAN, then you should not run the operation of macros. Perhaps the document contains a virus. Install the “patch” to your operating system and installed programs. Many support the automatic update (for example Windows XP or Linux Ubuntu). This protects you against viruses that spread by errors in the program or operating system. Network Attacks phenomenon is less common than viruses, but more dangerous. The purpose of a network attack can be misappropriation of information, or blocking of a single computer or an entire subnet. Network attacks are usually perpetrated by well-trained hackers, although cases are cases when it engaged in “kids” just for fun.
There are plenty of network attacks and their classifications, I will describe only the most famous. Brute force (brute force) is a method of overcoming the password protection. The idea is that the password is chosen enumeration of all possible variations. Can be used both on the network, and on the local machine. Sometimes brute force applied with the use of dictionaries. It is therefore necessary to use resistant to password guessing. And of course the password should not be meaningful word. Highly desirable to use numbers with letters, as well as uppercase and lowercase letters. Example: in case of burglary at a rate of 10,000 combinations per second (using the Latin alphabet in one case + digits) speed guessing the password of 4 characters 20 seconds of 8 characters in about 10 months.