View a list of simple ways you can avoid catching a computer virus

Your device can become infected with malware by simply browsing the internet

During a drive-by download attack, security flaws in a program or operating system (e.g., Windows) used to access online content are exploited, and malicious code is downloaded—for example, when loading a hacked webpage—onto a user's device without their knowledge. Restricting internet browsing to safe sites and installing security updates helps prevent these attacks.

A computer virus is a type of malware that self-replicates and spreads

Spread through emails, downloads, messaging services, and outdated software, viruses attach to programs, self-replicate, and infect other systems. They can delete files, steal data, and cause performance issues as they spread.

Some viruses evade detection by altering their own code or hiding in Microsoft Office

Computer viruses are often classified by how they spread or which files they infect, with the oldest ones—boot sector viruses—targeting systems that are active when a computer is turned on. Macros—custom codes in office productivity programs authored to automate tasks—spawned their own class of viruses.

Creating malware requires more than knowledge of programming languages

Because computer viruses, worms, and other malicious software reside within a computer's operating system, which manages computer hardware and software, cybercriminals writing effective malicious code must understand how the OS manages input and output, permissions, memory, etc. Knowledge of credentials and network access also helps create malware that easily spreads.

Safely explore historic viruses and other malicious software in the Malware Museum

Curated by the Internet Archive, this collection of more than 80 MS-DOS-era pieces of software can be experienced within an emulated environment to see what it would look like to trigger a virus on computers in the 1980s and 90s. Every piece of malware has a version available for download whose malicious capabilities have been removed.

Computer viruses can slow systems by allocating resources to malicious actions

Once infected software is run, instructions in the malicious code within the program or file can copy the code to various locations, exacerbating the infection and producing additional symptoms, such as slow performance, altered login credentials, changes to device settings, and system crashes.

Modern antivirus software searches for malicious behavior alongside malicious code

The first viral infections were identified by comparing the computer code of programs and files with a database of known virus codes, a method known as signature detection. The ongoing creation of new malware made databases continuously outdated, leading to the development of systems that detect patterns consistent with known viral activity.

The Melissa 'virus' helped associate pornographic sites with computer viruses

A worm-embedded document posted online enticed users to download and open it by alleging to contain passwords to paywalled explicit websites. Upon opening, the worm shared itself with 50 addresses in a user's Outlook contacts, masquerading as a friendly attachment. Its rapid spread overwhelmed email servers and caused $1.1B in damage worldwide.

Explore 3D models of some of the most dangerous viruses

Everyone has come in contact with common viruses—typically something like influenza (the common flu)—but sometimes they encounter more dangerous strains. While we're familiar with the symptoms that manifest, it wasn't until the advent of advanced microscopy that scientists could pin down the exact structure and behavior of various viruses.

Logic bomb viruses can awaken from a dormant phase without human input

Theoretically, computer viruses can remain idle indefinitely while awaiting specific user actions, as instructed by their code. However, logic bombs—embedded code that triggers when specific conditions are met—can automatically execute viruses, such as when a certain date or time is reached.

How to prepare for cyberattacks

An easy-to-digest checklist on the many ways you want protect yourself from a cyberattack before it happens, if it happens, and after it happens.

Explaining how open source systems like Linux can be secure, despite their public source code

While no computer system is immune to all cyberattacks and malware, the transparency of open-source technology means many thousands of developers can review and oversee the underlying code powering the software on an ongoing basis. This increases the likelihood of catching and patching vulnerabilities more quickly than smaller groups of cybercriminals looking to exploit them.

Peter Norton, for whom Norton Antivirus is named, questioned the threat of viruses

The software author was among several computer experts in 1988 who suggested that reports on the threat of computer viruses were exaggerated, referring to testimonials of infections and their spread as "urban legends."

Tips for reducing the risk of antimicrobial resistance

Antimicrobial resistance is bad news. But there are lots of things you can do to both protect yourself from superbugs and help keep the problem of antimicrobial resistance from getting worse. This page from the CDC offers clear, straightforward guidelines that can help keep you—and your loved ones—healthy.

Increasing contact between humans and wild animals is driving zoonotic threats

Zoonotic diseases, which spread from animals to humans, present one of the most significant emerging threats worldwide. Scientists have identified around 200 viruses capable of infecting humans, and unfortunately, the number of such diseases are on the rise—at least 60% of all emerging infectious diseases are zoonotic in origin.

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

Security technician hacks a voting machine to reveal its vulnerabilities

A technician bought an old, likely-decommissioned voting machine from 2013 and took it apart to see how a would-be hacker might be able to exploit its vulnerabilities. Get a sense of the needs for secure, up-to-date voting machines with this...

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

The oral, live virus vaccine is the most robust but carries more risks

The live virus vaccine, delivered via oral drops, induces the best protection in the body. Because it includes a live, weakened form of the virus there's an extremely small risk it can sicken recipients and potentially cause paralysis. Recipients also shed the virus in their stool, which can rarely lead to vaccine-derived cases of the virus if the virus mutates. (Some users may experience a paywall.)

How do vaccines work? Watch this brief 101

Watch this under-3-minute video explaining how vaccines use the body's immune system to prepare our bodies against viral and bacterial threats to our health.

In 2019, a laptop loaded with six of the worst malware in history and described as 'an exhibit of historical weaponry' sold for $1.3M.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Protecting yourself from West Nile involves avoiding getting bites and clearing standing water

The best prevention against West Nile is avoiding getting bit. That means covering your arms and legs with long, loose-fitting clothes, wearing insect repellant—on top of, not under sunscreen, and making your environment as inhospitable to mosquitoes as possible, including clearing any standing water.

The HPV vaccine reduces cervical cancer rates by 90% or more

Cervical cancer is the fourth most common cancer in women globally. Almost all cases (99%) are linked to infection with high-risk human papillomaviruses. However, cervical cancer is both treatable and preventable—and we may be able to prevent most cases through vaccination.

Learn how humans can protect coral reefs

When diving and snorkeling in environments containing reefs, avoid touching reefs, anchoring on them, or using sunscreen with active ingredients harmful to marine life. Properly recycling and disposing of trash in bins helps reduce microplastics and chemicals that can run off into wastewater and into the oceans.

Food companies usually issue recalls voluntarily and you can be automatically notified about them

Protecting yourself from food poisoning means staying on top of food recall announcements. Notices about these from the US government, which you can automatically receive after signing up at this link, note what products have been recalled by food companies. Companies alert the US Food and Drug Administration or the US Department of Agriculture when they issue recalls so the public can stay informed.

Web crawlers and internet archives and back-ups limit perfect erasure of online data

Crawlers are programs that automatically browse the internet for links and index pages for search engines to pull up when page content matches search queries. Networks of global data centers also create copies of content as fail-safes for potential failures to ensure access isn't ever lost.

Learn about the protocols that make navigating the internet possible

While TCP/IP sends data in packets to the correct destination and checks for errors, UDP omits such safety features to speed up data transfer for real-time communication and streaming. Software rules such as HTTP and HTTPS enable the transfer of content on the World Wide Web, while SMTP handles email messages between servers.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

Personal computers became more common in the late 1970s, making working from home more viable

As the internet and email became more popular in the 1990s, more infrastructure that would eventually support remote work was created. But the practice was still relatively uncommon until the COVID-19 pandemic, when white-collar workers first took to working from home en masse.

When you complete a CAPTCHA on a website to prove you are human, you may be unknowingly training algorithms for self-driving cars, whose systems require training data to help identify crosswalks, bicycles, and other outdoor objects.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Watch the cumbersome, but necessary, precautions healthcare workers must take to care for and protect themselves while caring for Ebola patients.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

Some researchers have labeled nomophobia, the fear of being without your phone, as 'the phobia of the 21st century.'

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Netflix profits when you're not watching, and its movies are designed that way—read a detail-rich critical essay exposing lesser-known Netflix takes

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

The first steps to rebuilding your credit score include getting to know exactly what's on your credit report and figuring out how far you are from the '700 club,' or 'good score' range.

Watch how deep-sea mining equipment collects and processes polymetallic nodules—metal-rich, potato-shaped rocks—from the ocean floor and creates environmentally damaging plumes of sediments.

Track the location of the Voyager probes, currently between 13 and 15 billion miles away from Earth.

The animatronic shark from Steven Spielberg's 'Jaws,' the first modern blockbuster, was a complex underwater apparatus called 'Bruce.'

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

20,000 letters to the advice columnist 'Dear Abby' provide insight into prevailing sex, religion, and LGBTQ fears, anxieties, and concerns from the 1950s onward.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.