Ransomware is a type of malicious software that encrypts a victim’s files. The attacker then demands a ransom from the victim to restore access to the data upon payment. Users are shown instructions on how to pay a fee to get the decryption key. The costs can range from a few hundred dollars to thousands, payable to cybercriminals in Bitcoin.

There are several different ways that ransomware can infect a computer. One of the most common methods is through malicious spam, or malspam, which is unsolicited email that delivers malware. The email might include booby-trapped attachments, such as PDFs or Word documents. It might also contain links to malicious websites.

Ransomware can also be delivered via drive-by downloading. Drive-by downloading occurs when a user unknowingly visits an infected website and then malware is downloaded and installed without the user’s knowledge.

Another vector of ransomware infection is through social engineering. This is often done through a phishing scam, where the user is tricked into downloading an email attachment or clicking a link.

Ransomware has become a significant threat in recent years, causing massive disruptions to government systems, healthcare providers, and large corporations. Notable ransomware includes WannaCry, Petya, NotPetya, and Ryuk.

Preventing ransomware involves a range of practices. This includes keeping systems and software updated, using reputable antivirus software, regularly backing up data, and avoiding suspicious emails or websites. If a system is infected, experts generally recommend against paying the ransom, as there is no guarantee that the hackers will restore access to the data. Instead, it’s recommended to restore the system from a clean backup and contact law enforcement.