Malware is an umbrella term which comprises an array of different kinds of cyber threats. Generally, malware is defined as a piece of malicious software that causes damage to clients, servers or networks once introduced into a device. Each kind of malware performs attacks in different ways, with different effects, and for a range of purposes.
These are the most common forms of malware that businesses and individuals often come into contact with. All are equally important to be aware of, and it is useful to understand how each works in order to be fully prepared and defend your business accordingly.
A trojan comes in the guise of a normal program or file, but then encourages users to download and install it. The attacker behind the trojan then gains access to the affected device, which allows them to steal data (including anything from login details to electronic money), to modify files, to monitor user activity, use the computer in botnets, and to install more malware.
This type of malware restricts access to the computer by either encrypting files on the hard drive or locking down the system. In the latter case, a message is then displayed urging the user to pay the malware creator to remove the restrictions. Ransomware is usually spread via a downloaded file or another kind of vulnerability in a network.
A virus is able to copy itself and spread. It is contagious – spreading to other computers by attaching itself to programs and executing code when a user accesses the infected program. As well as programs, viruses are also spread through script files and documents, and via web apps – exploiting cross-site scripting vulnerabilities.
Worms spread over networks by exploiting vulnerabilities in the operating system, consuming bandwidth and overloading servers. They are usually spread by emails with infected attachments. Worms can self-replicate and spread independently.
This kind of malware is designed for the purpose of giving remote access to the perpetrator, or for that perpetrator to control the device without being detected by security software. As a rootkit is so good at eluding detection, it can be very difficult to prevent or remove, not to mention extremely hard to spot in the first place!
The purpose of a bot is to automate specific operations on a device. They have become increasingly malignant in recent years. Botnets, for example, are used to enable multiple computers to be controlled by the parties behind them. Bots are also used to carry out DDoS (Distributed Denial of Service) attacks, as web spiders to scrape server data, as spambots rendering ads on websites, and for distributing malware via download sites.
AdWare is short for ‘advertising-supported software’. Often, AdWare software is combined with the more malign ‘spyware’, which tracks user activity and – worse still – steals information contained within the device. AdWare on its own steals space on a device and can slow it down, but usually functions as a revenue-generating tool for advertisers, and often comes via ‘free version’ downloads of software and applications.
Spyware monitors user activity, collects keystrokes, and harvests data (such as account information, logins and financial data). Often, spyware is also capable of modifying the security settings of software or browsers on the device, and interfering with network connections. Spyware exploits network vulnerabilities, hiding itself within legitimate software, or in trojans…
Bugs are usually the result of a mistake, often human error in source code or in the compilers of a program. At its most basic level, a bug is simply a flaw that creates an undesirable outcome. Minor bugs can go a long time without being discovered, as the effect on the program’s behaviour is pretty minimal. Not all bugs are so minor, however. More serious ones can cause a device to freeze or to crash altogether. The most severe bugs are security bugs, which can allow attackers to override access privileges, bypass user authentication, and steal data.
To find out more about protecting your business from these common types of malware, we recommend our indispensable guide to keeping your data safe. We explore the many ways that a company can defend itself from attack, the potential consequences of a breach, the best ways to ensure maximum coverage, and much more.
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