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Malware Threats - What Is, Types, and Examples


Malware is malicious software that enables the attacker to have full or limited control over the target system. Malware can damage, modify, and/or steal information from the system. There are various types of malware such as viruses, Trojans, worms, rootkits, spyware, and ransomware. A malware might enter the system through emails, file transfers, installation of random third-party software, and nonusage of quality antivirus software.

What is a Malware Attack?

A malware attack is a cyberattack where malware performs or executes unauthorized actions on a user’s system. Even criminal organizations, state actors, and well-known businesses have been accused of or caught deploying malware. If the impact of a malware attack is severe, it ends up being mainstream news just like other cyberattacks.

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Types of Malware

There are several types of malware. Let us take a look at them.

Malware Virus

It is malware that requires human intervention to run and disseminate. The following are the different types of viruses:

  • File Viruses: These viruses are infected executable files that infect other files when opened.
  • Macro Viruses: These viruses are Excel files that have malware written in VBS; when such files are opened, a macro gets executed and infects other files.
  • Master Boot Record Viruses: These viruses change or delete boot records that can render a system useless.
  • Polymorphic Viruses: These viruses are able to evade detection by changing their form frequently.
  • Stealth Viruses: These viruses hide in other legitimate files or services.

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Trojan Malware

Trojan is a malware that conceals itself in other legitimate files. When the files and software that are bundled with malware get installed, the malware too gets installed and executed. The following are the various types of Trojans:

  • Remote Access Trojans: These Trojans allow hackers to gain remote access to systems through covert channels without the knowledge of the user.
  • Data Sending Trojans: These Trojans steal data from systems and transmit it to the attacker.
  • Destructive Trojans: As the name suggests, these Trojans destroy files and services.
  • Security Software Disabler Trojans: These Trojans can disable system firewalls and antiviruses to prevent detection of other malicious files being downloaded and executed.

Worm Malware

Worms are similar to viruses but without the need for human intervention to run and propagate.

Rootkit Malware

Rootkits are extremely difficult to detect and just as impossible to remove unless the system is formatted.

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Malware Examples

Malware has a long history that dates back to infected floppy disks swapped by Apple II hobbyists in the 1980s and the Morris Worm that infected Unix machines in 1988. Some other examples of high-profile malware attacks are:

  • SQL Slammer that brought internet traffic to a halt within minutes of release in 2003
  • Zeus, a keylogger Trojan that targeted banking information
  • CryptoLocker’s code kept getting repurposed for malware projects of similar caliber and was the first example of a widespread ransomware attack
  • Stuxnet infected systems all over the world but only did real damage to the uranium-enrichment centrifuges at Natanz, the Iranian nuclear facility

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Malware Detection

The following is how you can detect malware-infected systems or networks. These are the signs that you need to look for:

  1. Extremely slow and unresponsive system
  2. Undeletable files
  3. Random folders or shortcuts inside folders
  4. Issues while shutting down due to certain running files or programs
  5. Change in default settings of PC
  6. Unnecessary running services or programs using up the processing power of the CPU
  7. Reboot issues
  8. Auto shutdown
  9. Unnecessary traffic patterns or traffic to destinations you never targeted
  10. Similar malware alerts by the antivirus on the network

Malware Removal

The following steps need to be taken after the detection of malware in the PC or network:

  • Removal: Sanitisation of the infected PC or network
  • Prevention: Ensure that the system and network is safe from similar events

For the removal process, the following basic steps can be taken:

  • Remove the system from the network, and disconnect all internet and intranet connectivity
  • Do not connect external drives as that might spread the malware to other systems
  • Perform a full scan on the PC with an updated antivirus program
  • Reboot the PC and update all software patches

If the removal is not successful, format the system and take the following prevention steps:

  • Schedule regular full scans using a legitimate antivirus
  • Keep your OS up to date
  • Avoid opening emails or attachments from untrusted sources
  • Scan external drives before inserting them into the system
  • Avoid downloading software from illegitimate sources
  • Backup critical information on an external drive
  • Avoid macro in Excel, if not required

Antivirus Sensor Systems

An antivirus or anti-malware is used to identify, prevent, or remove the malware present in the system. Antivirus can perform system checks and update the security of the system on a regular basis. There are various free as well as paid antivirus software available in the market.

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Malware Analysis Procedure

The malware analysis procedure involves the following steps:

  • Allocate the physical or virtual system: Infect the system with malware and identify the responses of the system. You can find ways to prevent or erase suspicious activities.
  • Make use of analysis tools: Find previous malware attacks that happened on the system and get detailed analysis.
  • Static property analysis: Analyze static properties to detect worms, viruses, Trojans, etc.
  • Interactive behavior analysis: Interact with malware and identify the reactions based on your actions.
  • Manual code reversing: Decrypt data to find the algorithm that generated the malware.
  • Combining malware analysis steps: Combine any two or more of the above-mentioned steps to find a combined solution.

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About the Author

Senior Reserch Analyst - Cloud Computing

Arpit has years of experience working with top-tier tech companies and has developed a plethora of knowledge in Data Analysis and Machine Learning. He currently holds the position of Senior Research Analyst in Cloud Computing. His passion for writing extends beyond the technical world, crafting profound narratives that bridge the gap between complex concepts and accessible understanding.