Top Examples of Malware Attacks

Malware refers to any software with a malicious purpose once deployed to a computer, mobile device, or network. Traditionally, these programs have been difficult to detect because attackers disguise compromised files as harmless images, PDFs, or trusted applications. In 2026, that challenge has intensified: security researchers are now tracking AI-generated and polymorphic malware that can rewrite its own code on every execution, producing a functionally identical but syntactically unique file each time it deploys — a tactic designed specifically to slip past signature-based antivirus tools.

It's important to note that while all computer viruses are considered malware, not all malware is a virus. To qualify as a virus, malicious software must be able to replicate itself and spread to other machines on its own. Ransomware, spyware, trojans, and worms are also classified as malware, even though each behaves differently — they're united by their shared goal of compromising the confidentiality, integrity, or availability of a system or its data

Almost all types of malware fall into one of two categories: method of infection and purpose once active. Some of the top examples of malware infection methods are listed below.

Different types of malware use different delivery methods to sidestep users' defenses, with infection generally occurring when a user opens a malicious file, clicks a compromised link, or scans a booby-trapped code on their device.

1. Phishing — Phishing remains the most common tactic attackers use to deliver malware, whether through a malicious email attachment or a link directing the user to download a compromised file from an online storage service. Mandiant's 2025 M-Trends report found email phishing responsible for roughly 14% of initial malware access, while Verizon's 2025 DBIR found phishing behind 16% of breaches overall. 
2. QR codes — Known as "quishing," this newer tactic embeds malicious links inside QR code images sent via email or posted in public spaces. Because the payload lives inside an image rather than clickable text, it often slips past traditional email filters — and lures the victim onto an unmanaged personal device outside the corporate perimeter. QR-based phishing attempts surged roughly 400% between 2023 and 2025, with over a quarter of all malicious links now delivered this way. 
3. USB drives — Cyber criminals still leave infected USB drives with enticing file names in public places, hoping curiosity will lead someone to plug the device in and unknowingly install malware.
4. Malicious websites — Hackers use compromised or lookalike websites — including social networking platforms — to deliver malware to unsuspecting visitors who are often unaware they've been exposed to a threat.
5. Infected Files & Software Supply Chains — Legitimate-looking files, software updates, and even trusted SaaS integrations can be compromised so that once opened or connected, they install malware without the user's knowledge. This has become especially common through OAuth token theft and supply chain attacks on trusted platforms, where a single compromised vendor integration can expose hundreds of connected organizations at once. 
6. Network Propagation — Some malware spreads automatically to other devices once it lands on a network, scanning for additional systems to infect without further action from the attacker.

Different types of malware have different purposes and goals to achieve once they infect the target system.

1. Steal information — Traditional information-stealing malware (keyloggers, spyware) records keystrokes and screen activity to capture sensitive data like credit card numbers or login credentials and send it back to the attacker.
2. Harvest credentials and session data — A newer and now more dominant category, infostealer malware quietly extracts saved passwords, browser cookies, and session tokens — not just typed keystrokes. Because stolen session tokens can let attackers bypass MFA entirely by reusing an already-authenticated session, infostealers have become a leading precursor to ransomware: research shows over half of ransomware victims had corporate credentials previously exposed in an infostealer log. 
3. Disruption and destruction — Ransomware takes control of a device or network, encrypting files until the victim pays (usually in cryptocurrency), and attackers frequently use it to disrupt organizations, hospitals, or government agencies. In 2026, many ransomware groups have shifted toward "double extortion" — stealing data before encryption even begins — and some now skip encryption altogether, relying purely on the threat of leaking stolen data to pressure victims into paying.
4. Command and control — This malware hijacks a device's resources to conduct other illegal activity, such as launching cyberattacks on other targets, hosting illegal files, or mining cryptocurrency without the user's knowledge. In 2026, attackers have also expanded this tactic to routers, IoT devices, and even AI infrastructure, recruiting them into large-scale botnets used for record-breaking DDoS attacks. 

3 Examples of Malware: Clop, Qilin, and Lumma Stealer

In addition to the core types of malware listed above, here are three malware threats you should be aware of in 2026:

1. Clop Ransomware: Active since 2019 and linked to threat groups TA505 and FIN11, Clop has become known for exploiting zero-day vulnerabilities in enterprise software rather than relying on traditional phishing-delivered ransomware. In its most recent campaign, Clop exploited a critical zero-day (CVE-2025-61882) in Oracle E-Business Suite, stealing data from dozens of major organizations — including Oracle itself — and shifting away from file encryption entirely in favor of pure data-theft extortion, following the same playbook it used in the 2023 MOVEit breach.

2. Qilin Ransomware: Qilin (also tracked as Agenda) has emerged as the highest-volume ransomware-as-a-service operation on the planet, logging well over 1,000 victims on its leak site as of 2026. Affiliates rent access to Qilin's Rust-based ransomware, which is difficult for traditional antivirus tools to detect, and pair it with double-extortion tactics — encrypting files while also stealing data and threatening to publish it. Qilin and related groups have also been observed using "Bring Your Own Vulnerable Driver" (BYOVD) techniques to disable endpoint detection and response (EDR) tools before deploying their payload. 

3. Lumma Stealer: Lumma is a subscription-based infostealer that harvests saved browser passwords, autofill data, banking session details, and cryptocurrency wallet files — but its most dangerous capability is stealing session cookies and authentication tokens, which let attackers hijack an already-logged-in session and bypass MFA entirely. In May 2025, Microsoft, the U.S. Department of Justice, and international law enforcement seized roughly 2,300 domains tied to Lumma's infrastructure in one of the largest infostealer takedowns on record. Within weeks, it was back — rebuilding its infrastructure and spreading via "ClickFix" lures, fake CAPTCHA prompts that trick users into pasting malicious commands into their own Windows terminal. By 2026, Lumma is once again one of the most active credential-harvesting tools in the world, underscoring how infostealers now sit at the front of the ransomware kill chain. 

How to Prevent Malware Infection

While knowing how to detect and remove malware is useful, prevention is far more effective than a cure. The goal is to combine strong software defenses with clear security guidelines for employees to prevent infections and limit their impact when they do occur.

Steps you can take include:

1. Reduce administrative privileges: Users shouldn't have administrative access on their workstations, which prevents them from accidentally disabling security controls or installing unwanted software. This is especially critical today, as several ransomware groups now use "Bring Your Own Vulnerable Driver" (BYOVD) techniques to disable endpoint detection tools — a tactic that's far harder to pull off on a properly locked-down, least-privilege device. 

2. Back up your data and protect the backups: Protect against ransomware by maintaining regular backups so you can restore encrypted files without paying attackers. In 2026, it's just as important to isolate and immutably protect those backups, since many ransomware operators now specifically target backup systems before deploying their payload to eliminate an easy recovery path.

3. Control file sharing and downloads: Limit the platforms and services employees can use to download or share files. Free and public file-sharing services remain a common way to disguise malware as legitimate files — and this now extends to fake software cracks, pirated media, and "ClickFix" style prompts that trick users into pasting malicious commands directly into their own terminal. 

4. Deploy phishing-resistant MFA: Traditional MFA — SMS codes, push notifications, one-time passcodes — is no longer enough. Infostealer malware now routinely harvests session cookies and authentication tokens, letting attackers hijack an already-logged-in session and sidestep MFA entirely. 

5. Deliver regular security awareness training: Ongoing training remains essential, but the content needs to evolve. AI-generated phishing emails are now grammatically flawless and convincingly personalized, meaning "watch for typos" is no longer useful advice. Training should instead focus on verifying unexpected requests and reporting suspicious activity quickly, since stolen credentials often sit on criminal marketplaces for days before being used.

Staying Ahead of an Ever-Evolving Threat

Malware isn't going away — if anything, 2026 has shown it's becoming faster, stealthier, and harder to catch with traditional tools, from AI-generated ransomware that rewrites its own code to infostealers that hijack sessions and sidestep MFA entirely. But that doesn't mean your organization is defenseless. The fundamentals still work: limiting administrative privileges, maintaining isolated backups, deploying phishing-resistant MFA, and building a culture of security awareness can stop the vast majority of attacks before they ever take hold. Combine those habits with proactive antimalware protection, and you turn malware from an inevitability into a manageable risk.