Virus detection software can't catch everything. While always-on, cloud-based tools offer great protection for small businesses, insidious Trojans, worms and malware can still slip through defenses.

One of the best ways to improve your defenses against viruses is to increase your knowledge of potential issues. Here are the top five signs you or your employee is about to download a virus and how to avoid it.

1. Socially Suspect

While employees never intend to download malicious files or compromise corporate networks, malware threats remain a major concern for today's businesses. Often, the problem stems from social engineering techniques designed to convince users that the file they're downloading or email they're responding to is legitimate. For example, emails may warn that a bank account is going to be suspended and request sensitive information, or ask users to download a software update in a malware-laden attachment. To avoid this problem, employers must train their staff to recognize common signs that an email is illegitimate. These include aggressive language demanding immediate action, grammar mistakes or incorrect email addresses and links.

2. Recognizable Risk

Emails that carry the letterhead and relevant details of a recognized institution or virus detection company can be deceiving. The content contains logos, contact numbers, real employee names or other information to trick the reader, often coupled with dire warnings about necessary updates or compromised accounts. Users can avoid this problem by always entering a site's URL manually and log in through an official Web portal, rather than using a link provided in an email.

3. Physical Failures

Email is the top source for malware, but physical devices such as USB keys may also transmit dangerous software. All it takes is a single employee using a compromised device to spread a virus between networked computers. To avoid this problem, leverage cloud storage technology to share files with approved devices. This strategy can also be beneficial for employees who work remotely or travel often, as they can access this information on their mobile devices.

4. Nasty Names

File name tricks remain a popular way to convince users that malware-laden files are safe to download, as How-To Geek explains. Some file names can be altered so that executable files, usually marked with a ".exe" at the end of the file name, may look like an innocuous picture or music file. Your best defense is to use real-time firewalls and virus protection programs that scan any file before downloading, and to configure computers to ask for permission before running a new executable file.

5. Wireless Worries

"Free" Wi-Fi hotspots in popular locations like coffee shops and airports that offer no wireless protection can leave a device vulnerable to a range of risks. Hackers simply give their fake network a common name, such as "CoffeeShop WiFi" or "Free HotSpot," and ask users to create an account that includes email and password identifiers. Information transmitted over these networks can be captured by malicious users, as well. Only use trusted, secure Wi-Fi networks to keep your computer and your information safe.

Want better virus detection? Understand the top five signs of imminent infection and take action before threats materialize.

Tags: social media sites malware infection virus detection corporate networks physical device malware detection