# Virus Attacks and How to Defend What is heuristic scanning? > Scanning using a rules-based approach What malicious activity did the Rombertik virus attempt? > It overwrote the master boot record Which of the following should be the least important consideration when purchasing antivirus software? > Cost The first known ransomware was the 1995 PC Trojan > False In the event of a virus infection, the first priority is to contact the IT department. > False, the first priority is to stop the spread of the infection What is the most common method of virus propagation? > Through e-mail attachments In the context of viruses what is a .dat file? > A file with virus definitions The unfortunate side effect of heuristic scanning is that it can easily lead to false positives > True What is active code scanning? > Scanning for active web elements (scripts, ActiveX, and so on) Which of the below are famous Trojan Horses? > Netbus, Finfisher --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://wiki.zacheller.dev/network-security/courses/isci-cnss-course/virus-attacks-and-how-to-defend.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.