Unfortunately, most computer users have experienced the painful effects of malware: malicious software, code snippets, or content designed to carry out nefarious acts against your systems—even if just to wreak general havoc.
Volumes have been written about the myriad of malware types and the vast range of malicious software programs associated with each. The following are 13 of the most common types and how to combat them.
Adware is software that enables the display of banner advertisements when the program is running.
These programs seem to be legitimate and even useful, effectively tricking users into its installation and use.
Malicious software designed to copy itself and propagate from one system to another—usually by attaching itself to program files.
A worm will infect other computers but—unlike viruses—do not propagate by infecting other files. Worms are known for their self-replication abilities.
A program that installs itself in such a way that the infected computer can be accessed and controlled remotely from anywhere.
Greyware is essentially software that may be viewed as useful in some cases but which also includes components that may be seen as malicious or annoying in other contexts.
This particular type of malware uses a network of computers—called a botnet—manipulated by a robot under the control of a cyber attacker or bad actor.
8. IRC Bots
An IRC bot is a set of scripts or an independent program that connects to Internet Relay Chat (IRC) as a client, and so appears to other IRC users as another user. The owner/attacker then uses it to launch spam and DDoS attacks.
A dropper is a program that has been designed to “install” some sort of malware (virus, backdoor, etc.) to a target system.
10. Browser Hijacker
This term covers a range of malicious software, but generally speaking browser hijacking software is external code that changes browser settings—usually without the user’s knowledge.
11. Keystroke (key) Logger
Keystroke loggers—or key loggers for short—are programs that capture and send which keys are pressed on a keyboard to a third party, usually a cyber attacker or bad actor.
Phishing is a common form of social engineering that uses impersonation—usually in the form of confirmation/validation emails—to steal user credentials and other information.
Smishing is essentially phishing on mobile devices. The “sm” is derived from SMS, the protocol used by cyber attackers to transmit smishing text messages.
Ransomware encrypts a computer’s files and alerts the user that an amount must be paid for the decryption key to be disclosed—usually before a specified deadline, pending deletion.
Rogueware is fake software that attempts to steal money from users by tricking them into paying for the removal of nonexistent threats.
Rootkits are software designed to open up areas of a computer or software—such as the kernel or reserved memory spaces—that it would not otherwise be allowed to access.
Spam is simply junk email or unsolicited bulk email that often contains malicious elements for setting up bigger cyber attacks.
18. Image Spam
Image spam uses images as all or part of an email’s text in a popular attack method known as “clickjacking,” where users are tricked into revealing confidential information or relenting control of their computers while clicking on seemingly innocuous web page elements (e.g., images, text, etc.).
Scareware comprises several classes of scam software that are of limited or no benefit to users, sold to consumers via certain unethical marketing practices—sometimes carrying malicious payloads.
Spyware are programs that collect information about a person or an organization without that entity’s consent and/or knowing.
Vishing attackers use the phone to scam users into giving up privileged information that in turn will be used for identity theft.
22. DNS Changer Malware
This type of malware modifies a computer’s Domain Name Service (DNS) settings to point to the attacker’s rogue servers, which then injected their own advertising into websites and pages.
23. IP Spoofing Malware
In this highly common attack method, an attacker sends IP packets from a false source IP address to hide its true origins.
24. Tracking Cookie
Though usually inocuous, tracking cookies allow vendors and third-parties to track, store, and share your personal information. Cookies are also commonly used by cyber attackers for nefarious purposes.
Pharming works by installing malicious code on computer or server that allows traffic to be misdirected to another imposter website without the user’s knowledge or consent.
A bit of a throwback—but no doubt still considered a threat to the handful of MS-DOS users still in existence. Vienna is a virus that—when triggered—searches for .com files on the system and infects one of them.
27. Cutwail Botnet
This botnet–one of the largest of its type to date—affects Microsoft Windows computers, forcing them to send spam emails en masse.
28. Hybrid Malware
As its name implies, hybrid malware combines various types of malicious software and techniques for a specific malicious purpose.
Prevention and Countermeasures
Antivirus solutions are increasingly ineffective for combating malware and other types of cyber threats. Current defenses that rely on known malware fingerprints or signatures will clearly fail in the presence of unknown threats. The best two measures for maintaining a strong security posture are still personal vigilance—being aware of current cyber threats, not opening suspicious emails, avoiding dubious websites—and staying on top of operating system and software patches/updates.
- M. Bailey, J. Oberheide, J. Andersen, Z. M. Mao, F. Jahanian, and J. Nazario. Automated Classification and Analysis of Internet Malware.
- Malware Analysis – International Journal of Scientific & Engineering Research Volume 4, Issue 1 by Samanvay Gupta.