As many as 500 million smart devices worldwide come pre-installed with malware that lets strangers use a person's internet connection.

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.

Many of the first researchers and hobbyists who created viruses and worms showed a natural curiosity in experimenting with and designing such software to make a name for themselves and advance the field of computer science. In the future, AI-augmented malware may adapt in real-time or design enhanced cryptojackers, infostealers, and ransomware for cybercriminals.

Insecure devices connected to the Internet of Things pose risks to the entire network, which cybercriminals can hijack to compromise infrastructure and private resident data. Poorly secured systems that become inoperable can undermine the promise of smart cities by worsening the quality of life.

Some of the earliest significant pieces of malware—the Creeper worm and the Elk Cloner virus—displayed silly messages to users without causing major harm. As computer science has advanced, malware has become more easily spread, incorporated social engineering to manipulate users, targeted infrastructure systems, and been used by governments for virtual espionage.

Computer viruses require user interaction to execute a file and spread, whereas worms can self-replicate across systems without human intervention. Ransomware locks systems until a key is provided, spyware tracks and reports user activity to a third party, and trojans disguise various types of malware as legitimate software.

Browsing the dark web requires onion routing, which prevents visitors from being identified and the locations from which they connect from being traced. This has been useful to activists in environments affected by political oppression or instability. However, those unfamiliar with navigating the space may encounter malware and network attacks from denizen hackers.

Although encryption existed to mask the content of communications across the internet before the 1990s, those managing overseas network infrastructure could determine a spy's affiliation based on where they saw data sent to and received from. To keep this information secret, the US Naval Research Laboratory developed onion routing, which enabled anonymized web browsing. The release of the technology to the public obscured sensitive communications further by growing the volume of anonymous data.

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.

The untraceable cryptocurrency Monero is used in about 60% of transactions across more than 37 active marketplaces that sell copyrighted materials, private information, and phishing kits—tools that help bad actors more easily create fake sites to steal users' data—for financial fraud.

Currently, technology exists to scrape and download data from webpages, which can then be analyzed to identify a user's information. However, scrapers cannot access or remove personal data from dark websites because they are often protected by paywalls, rendering monitoring ineffective beyond reporting publicly available data breaches.

While there are dozens of different types of cyber attacks, this article explains the top 20 most common network attack examples, including phishing, whale-phishing, and spear-phishing attacks. Learn how to best protect yourself.

The first significant malware was the Morris worm in 1988, which caused an estimated $10,000 to $10M in damage to computers. With $38B in damage caused, Mydoom is the most costly piece of malware in history. Spread via email and, at one point, accounting for about 25% of all messages sent worldwide, the malware infected computers to create a botnet that launched cyberattacks.

Despite encrypting data and relaying it within the Tor network, traffic between the network exit and the final destination is no longer hidden and can be captured. Law enforcement agencies can also attempt to deanonymize users by monitoring and matching data signal patterns entering and leaving the network via a correlation algorithm.

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.

Cybersecurity researcher John Hammond explores the effectiveness of a dark web search engine, leaks from ransomware group data breaches, and a categorized index of dark web links, including some that are alleged to host malware. Many dark web sites are no longer active or host scams to fool unsuspecting visitors.

An HP analysis found that 77% of cybercriminal marketplaces require vendors to purchase a license to sell their products, which can cost up to $3,000. About 92% of these marketplaces also use a third-party dispute-resolution service to handle customer service issues, thereby promoting "honor among thieves."

A mix of centralized cloud infrastructure and legacy protocols leaves the internet susceptible to downtime from minor cyberattacks or software bugs, infrastructure damage caused by extreme weather, and human error if a DNS service provider—the internet's phone book—or a backend system, such as Amazon Web Services, were compromised.

A computer expert who created a system to track down sources of revenge porn and an investigative journalist joined forces to investigate digital abuse. Their investigations focused on so-called clear nets, websites that make up the web most users surf. Then, they turned their investigation toward the dark web, where they found a child abuse website with more than 1 million registered users.

Besides those authored in research labs as proofs of concept for self-replicating software, hobbyists would create malware that played music or displayed text and animations that intentionally revealed the infection as a means of showing off, rather than hiding their spread.

Botnets are a network of computers that have been infected with a variant of malware that coordinates and leverages them for automated mass attacks such as data theft and crashing servers. This interactive map highlights where botnets have been located between 2014-2020.

On their YouTube channel, Malware historian Daniel White has documented what happens when various types of malware—mostly from the 1980s and 90s—run on a computer or Nokia cell phone. The demonstrations were safely conducted within virtual machines—older operating systems run within contained windows of modern software, resembling a picture-in-picture setup.

These attacks can manipulate AI behavior by hiding instructions in websites and PDFs that become part of training data. The more companies connect sites, services, and sensitive datasets to AI tools, the greater the chances of exposure to malicious code.

'Bossware' tools help employers make sure their remote workers aren't slacking off on the job, using surveillance technology to monitor employee computer activity and more.

Researchers have uncovered online storefronts allegedly run by members of various mafia or hitmen that offer to harm or murder individuals in exchange for monetary payment. However, no known murder has been attributed to any of them, and cybercrime task forces believe them to be scams (warning—sensitive content).

By using a network of devices, including digital meters, sensors, and controllers, smart grids can quickly detect mechanical issues and fluctuations in supply and demand, automatically adjusting electricity flow to prevent cascading failures. While this is important for variable solar and wind power generation, many of these computer systems are designed to be controlled remotely, which increases the risk of malicious access.

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.

Various countries around the world, including China, Russia, and Iran, control their local DNS infrastructure, allowing them to block access to online content by preventing the internet "phone book" from finding the IP addresses for specific URLs. Government-controlled internet service providers can also cut off access entirely or throttle specific traffic.

It did not distinguish between visits to malicious sites and traffic to legitimate institutions with .onion domains, such as the BBC or Buzzfeed, and thus claimed that 6.7% of anonymized users engage in nefarious activity. The low percentage still highlights that most users of the technology underlying the dark web do not use it to browse the hidden portion of the internet.

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.

In September 2025, a Chinese state-sponsored group targeted 30 large tech companies, financial institutions, chemical manufacturing companies, and government agencies by manipulating Claude Code, having succeeded in infiltrating a small subset. The cyberattack is believed to have been the first of its scale carried out without major human intervention.

The dead internet theory proposes that bots create most online content. These bots are believed to create social media posts to boost engagement and increase advertising revenue. However, the accounts doing the liking and commenting are also believed to be bots. The theory suggests governments use bots to manipulate public opinion.

Because this type of malware requires human intervention, such as plugging an infected flash drive into a computer or downloading and running an infected file, the chance of infection can be greatly reduced by being cautious about unfamiliar emails, attachments, and links. Keeping systems up to date with the latest security fixes is also crucial.

Despite providing relief from neurological conditions, patients are left stranded when the companies that make these devices shut down. The lack of regulation means patients often face technical failure, insurance battles, or risky surgeries to maintain their quality of life.

Displaying as LOVE-LETTER-FOR-YOU.TXT on Windows computers, the file appeared to be a love letter, which many users willingly opened. However, the file contained a script that damaged and hid files, caused Internet Explorer to download software to help steal passwords, and copied itself to all Outlook contacts to continue spreading.

Demographically, smartphone dependency is greatest among those below 30, Hispanics, Blacks, economically disadvantaged individuals, and those with less formal education. Home broadband adoption is at 78%, with rates highest among suburban residents.

Demographically, smartphone dependency is greatest among those below 30, Hispanics, Blacks, economically disadvantaged individuals, and those with less formal education. Home broadband adoption is at 78%, with rates highest among suburban residents.

Polling finds that while most Americans have home broadband and smartphones, digital divides persist. Young adults, Hispanic adults, and lower-income households are significantly less likely to subscribe to home broadband and more likely to rely on smartphones as their primary means of internet access.

Data is encrypted at least three times before being sent to a node—a server that can only decrypt one layer. Then, the underlying encrypted data is relayed to another node, and the process repeats until all layers are decrypted. Thousands of possible nodes make it extremely difficult to trace activity within the system.

Being able to track how users behave on websites is a massive opportunity for companies to hone their products, target their ads, and more. Dozens of trackers are on the average website you visit, depending on how you deal with that site's cookie policy, and Google is the chief tracker of them all. Learn about these companies and what they are tracking with this informative blog visualization.