Malware Explained

What is Malware?

Malware, short for "malicious software," is a general term for programs specifically created to interfere with or harm computer systems and files without authorization. In contrast to regular programs that are meant to assist users, malware is made to damage systems, steal data, or take advantage of resources.

Malware vs Virus

Despite being used interchangeably, malware and viruses are not the same. Malware is a broad category that covers all types of malicious software, whereas a virus is just one specific type of malware.

• • Aspect
  • Definition
  • Infection Method
  • Intention
  • Examples
• • Malware
  • Umbrella term for all malicious software, including viruses, worms, trojans, ransomware, spyware, etc.
  • Phishing, drive-by downloads, malicious attachments, USBs, or system vulnerabilities. Can also be fileless and be delivered via in-memory attacks.
  • Steal data, encrypt files, spy on users, hijack resources, or disrupt operations.
  • Ransomware (WannaCry), Trojan (Zeus), Spyware, Worms, Fileless malware.
• • Virus
  • A specific type of malware that attaches to files or programs and spreads when those files are shared.
  • Requires attaching to a host file or program to spread.
  • To corrupt or damage files and programs.
  • ILOVEYOU virus, Melissa virus.

What is a Malware Attack?

When malicious code is successfully installed on a victim's device, often without the victim's knowledge, it is known as a malware attack. After that, this code can be used to remotely take over the system, encrypt files, log keystrokes, and steal confidential information. Malware attacks target people, companies, and even governments every day and continues to be one of the biggest cybersecurity threats, capable of causing everything from downtime to destruction of critical infrastructure. Malware can take many different forms, but its fundamental objective is always the same: to gain unauthorized access and exploit it.

Types of Malware

Different malware have varying modus operandi and doesn’t act in the same manner. While some steal information covertly for months (also known as persistence), others spread quickly throughout networks.

• Viruses
  Viruses attach themselves to trustworthy files or software and propagate when those files are shared. A virus can destroy data completely, slow down systems, or corrupt files depending on the intent it’s crafted for.
• Worms
  In contrast to virus, worms do not require user interaction. They spread independently throughout networks and self-replicate, taking up resources and bandwidth.
• Trojans
  Trojans are malicious programs that pose as trustworthy software. Once installed, a Trojan attack can spread more malware, steal data, or open backdoors for the attacker to exploit.
• Spyware
  Spyware is a type of malware that secretly monitors user activity on a computer. It can capture keystrokes, track browsing habits, and even steal financial information, often exploiting this data for malicious purposes.
• Adware
  Adware is a software that bombards users with intrusive, unwanted advertisement. Though adware is often less harmful, it can at times, open the door to more dangerous malware.
• Ransomware
  Ransomware encrypts sensitive files or locks you out of your system, then demands payment for access to be restored. It can cause severe damage to an organization’s finances and reputation, with infamous attacks like Ryuk and WannaCry serving as stark reminders of its destructive power.
• Fileless malware
  Fileless malware is a stealthy and advanced attack that runs directly in system memory, leaving no files on disk. This makes it far harder for traditional/legacy security tools to detect and prevent.
• Rootkits
  Rootkits grant attackers deep, hidden access to a system, giving attackers privileged, behind-the-scenes access. They can disable security software, alter critical system processes, and conceal other malicious programs, making them exceptionally difficult to detect and remove.

How does a Malware Attack Work?

Malware attacks usually occur in the following steps:

• Delivery: Phishing emails, malicious attachments, hacked websites, or infected USB drives are some of the ways that malware is spread. Attackers frequently use this as their "entry point."
• Execution: After entering, malware carries out its destructive payload. For instance, spyware may start recording keystrokes, while ransomware may start encrypting files.
• Persistence: By altering system settings, inserting themselves into the registry, or passing for trustworthy processes, many malware strains try to remain undetected.
• Exploitation: At this point, malware performs its intended function, which may include data theft, credential exfiltration, cryptocurrency mining, or file hostage taking.
• Spread: Some viruses and worms can spread by self-replication over networks or through detachable media.

Data breaches, outages, monetary losses, harm to one's reputation, or even threats to national security could have disastrous results.

What are the consequences of malware?

From an enterprise standpoint, malware can cripple organizations due to its adaptability and versatility. The consequences are far-reaching, often extending beyond technical disruption. Malware doesn’t just affect systems, it threatens the very credibility of an organization.

• Data theft
  Malware has the ability to steal credit card numbers, personal information, and company intellectual property. The stolen data can then be sold on the dark web, used for identity theft, or leveraged in corporate espionage, causing long-term damage beyond the initial breach.
• Financial damage
  The financial repercussions of malware are dire, ranging from fraud to ransomware demands. Organizations may also face steep regulatory fines, costly lawsuits, and significant expenses in recovery efforts, not to mention the indirect costs of lost business opportunities during downtime.
• Espionage
  Spyware and trojans that aim to steal private data frequently target governments and businesses. These attacks can undermine national security and provide adversaries with valuable intelligence, creating risks that extend into geopolitics and competitive markets.
• Disruption
  Apart from the financial motive, malware attacks are also sometimes used to create chaos by erasing files, taking over systems, or stealing resources. Such disruptions can cripple IT infrastructure, halt essential services, and leave organizations scrambling to restore normal operations.

Real-world examples of malware attacks

Some malware attacks in the wild have garnered media attention throughout history due to their scope and severity. Here are a few attacks that have occurred in the past:

How to detect malware?

Malware detection is essential for softening the blow, minimizing the damage posed due to an impending attack. Some strains are readily apparent, while others are concealed for extended periods of time, waiting for the ideal time to show its true colours. Though it might not be evident outright, there are a few signs that can indicate the onset of malware detection. However, no matter how well your endpoint security is, running into newer, more sophisticated malware strains is inevitable. When you do, advanced malware protection is your best bet at thwarting those threats.

Signs your computer is infected with malware

• System performance issues
  One of the most common red flags is a noticeable drop in performance. Slow boot-up times, frequent system crashes, frozen applications, or a general lag that wasn’t there before can all signal a potential infection. On mobile devices, a rapidly draining battery or sudden loss of storage space may point to malware silently running in the background.
• Unexpected pop-ups and ads
  Intrusive advertisements, error messages, or browser windows appearing out of nowhere can indicate adware or other malicious software. Pop-ups appearing in unusual places especially at an unusually high frequency can point towards system compromise.
• Unauthorized system changes
  Malware usually tampers with settings without user consent. Alterations like unfamiliar apps being installed or even a different desktop wallpaper/background are telltale signs of malicious, unwanted software at work.
• Suspicious network and account activity
  Sudden, abrupt surges in data usage, connections to unknown IP addresses, or unusual outbound traffic may indicate that malware is attempting to communicate with its attackers.
• Disabled security tools and locked files
  Another worrying sign of a malware infection is when your antivirus or security tools suddenly stop working. Some malware disables protection to avoid detection. In some cases, ransomware may delete your backups before encrypting and locking you out of files, until payment is made.
   

Common malware detection methods

• Signature-based detection
  Commonly used by traditional/legacy antivirus, signature based detection looks for signs of malware against a known database of malware. Despite being the detection mechanism used by legacy AV, signature based detection is less effective against novel and sophisticated malware than it is against more established threats.
• Behavioral detection
  Behavioral analysis focuses on identifying anomalies or unusual activity in applications or processes, such as unauthorized file encryption, abnormal network connections, or unexpected system changes. By flagging actions that deviate from normal patterns, behaviour based detection can detect zero-day threats and fileless malware that traditional signature-based tools might miss.
• Heuristic detection
  Heuristic detection uses algorithms to identify suspicious code or behavior that resembles known malware. Instead of relying solely on signatures, it analyzes how code is written or how a program behaves, which helps uncover new or modified threats. While powerful, it can sometimes generate false positives, requiring careful tuning.
• Endpoint Detection and Response (EDR)
  Real-time process tracking enables quick identification and reaction to emerging threats. EDR continuously monitors processes and activities across endpoints in real time, providing detailed visibility into potential threats. With capabilities like threat hunting, incident forensics, and automated remediation, it allows security teams to quickly detect, investigate, and respond to attacks, especially advanced threats that bypass traditional antivirus. EDR has become a cornerstone of modern endpoint security.

Best practices to prevent malware attacks

Prevention is the best defense against malware and a few basic practices can significantly limit the damage dealt by the attack or even prevent it from happening in the first place.

• Next-Gen Antivirus (NGAV)
  Unlike traditional antivirus, NGAV uses AI/ML based behavioral analysis and intelligence to detect advanced threats like ransomware and fileless malware. By going beyond signature-based detection, NGAV offers the surest way of defending against evolving malware.
• Patch and update management
  Keeping operating systems, applications, and firmware up to date is one of the simplest yet most powerful defenses against malware. Regular updates close known vulnerabilities that attackers frequently exploit. Automating patch management wherever possible helps ensure critical fixes are applied without delay.
• Application control
  Application allowlisting/blocklisting ensures that only approved, trusted software can run on systems. By blocking unauthorized or unknown applications, it reduces the chances of malware executing in the first place.
• End user awareness training
  Regular awareness programs can teach staff to recognize phishing emails, avoid suspicious downloads, and follow safe browsing practices. This way, informed users are less likely to fall victim to social engineering or careless mistakes.
• Multi-Factor Authentication (MFA)
  MFA adds another layer of verification on top of passwords for added security. This can be a one-time code, mobile app confirmation, or biometric factor, making it much harder for malware or stolen credentials to be used for unauthorized access.
• Device control
  External devices such as USB drives can serve as malware carriers via insiders or bad actors. Strict device control policies, such as limiting or disabling USB usage reduces the risk of infections spreading through removable media.
• Endpoint hardening
  Reducing the attack surface is key to preventing infections. Endpoint hardening involves disabling unnecessary services, closing unused ports, and enforcing strong configuration baselines to make systems less vulnerable to malware exploitation.
• Principle of Least Privilege
  Limiting access rights ensures users only have the permissions necessary for their roles and scope. This prevents malware from gaining high-level or admin access if a compromised account is exploited, reducing the potential scope of damage.

How to mitigate a malware attack?

When the strongest defenses are breached, it makes a well-prepared attack response plan more crucial. Malware mitigation focuses on limiting damage, restoring operations quickly, and preventing a repeat incident. Here are a few ways organizations can deal with a malware attack.

• Immediate isolation
  As soon as the first sign of infection is detected, the priority is containment. Compromised systems should be quarantined or disconnected from the network to prevent the malware from spreading laterally to other devices or servers. Swift isolation helps minimize damage and buys valuable time for response teams.
• Proactive threat hunting
  While containment is underway, it is advisable for security teams to search the environment for other signs of compromise. Malware often leaves behind hidden persistence mechanisms or remnants that can lead to secondary infections. Proactive threat hunting that leverages logs, endpoint detection and forensic analysis ensures that no remnants of the attack go unnoticed.
• Backup and recovery management
  Regular, verified backups are key to effective recovery in an event of a malware attack. Clean offline or immutable backups allow organizations to restore systems and data without succumbing to ransom demands. It is also recommend to frequently test backups to reduce downtime and embrace business resilience.
• Post-incident review
  Every attack provides lessons. After containment and recovery, conducting a thorough review is important to determine how the malware infiltrated, the weaknesses it exploited and ascertain if the response efforts were optimal.

How to remove malware?

Malware removal, especially in enterprise environments demands more than just cleanup. Malware Protection Plus leverages AI-driven detection, behavioral analysis, and real-time remediation to not only block active threats but also eliminate hidden payloads, unaware driveby downloads, registry changes, and persistence mechanisms that attackers leave behind.

With automated sensor updates and continuous endpoint scanning, Malware Protection Plus stays ahead of evolving malware variants without depending on any definition updates or signature databases. Security teams benefit from centralized visibility, faster incident response, and reduced dwell time, ensuring compromised systems are restored to a trusted state with minimal business disruption.

Malware defense with Malware Protection Plus

Malware Protection Plus is built to go beyond traditional antivirus tools, offering layered defense against today’s most advanced threats. By combining signature-based detection with AI-driven analysis, behavioral monitoring, and real-time response, it protects endpoints from ransomware, spyware, fileless attacks, and more. With automated updates, seamless remediation, and centralized visibility, Malware Protection Plus ensures organizations can detect, stop, and recover from malware faster without any downtime and added complexity for IT teams.

Meet the author

Manish Mandal

Manish is a cybersecurity and product marketing expert with ManageEngine's Unified Endpoint Management and Security solution. With over five years of experience, he leverages technical expertise and storytelling to create blogs, reports, and resources that empower IT leaders to build resilient defenses against modern cyber threats.