E-mail has spawned one of the most significant forms of cybercrime—spam, or unsolicited advertisements for products and services, which experts estimate to comprise roughly 50 percent of the e-mail circulating on the Internet. Spam is a crime against all users of the Internet since it wastes both the storage and network capacities of ISPs, as well as often simply being offensive. Yet, despite various attempts to legislate it out of existence, it remains unclear how spam can be eliminated without violating the freedom of speech in a liberal democratic polity. Unlike junk mail, which has a postage cost associated with it, spam is nearly free for perpetrators—it typically costs the same to send 10 messages as it does to send 10 million.

One of the most significant problems in shutting down spammers involves their use of other individuals’ personal computers. Typically, numerous machines connected to the Internet are first infected with a virus or Trojan horse that gives the spammer secret control. Such machines are known as zombie computers, and networks of them, often involving thousands of infected computers, can be activated to flood the Internet with spam or to institute DoS attacks. While the former may be almost benign, including solicitations to purchase legitimate goods, DoS attacks have been deployed in efforts to blackmail Web sites by threatening to shut them down. Cyberexperts estimate that the United States accounts for about one-fourth of the 4–8 million zombie computers in the world and is the origin of nearly one-third of all spam.

E-mail also serves as an instrument for both traditional criminals and terrorists. While libertarians laud the use of cryptography to ensure privacy in communications, criminals and terrorists may also use cryptographic means to conceal their plans. Law-enforcement officials report that some terrorist groups embed instructions and information in images via a process known as steganography, a sophisticated method of hiding information in plain sight. Even recognizing that something is concealed in this fashion often requires considerable amounts of computing power; actually decoding the information is nearly impossible if one does not have the key to separate the hidden data.

In a type of scam called business e-mail compromise (BEC), an e-mail sent to a business appears to be from an executive at another company with which the business is working. In the e-mail, the “executive” asks for money to be transferred into a certain account. The FBI has estimated that BEC scams have cost American businesses about $750 million.

Sometimes e-mail that an organization would wish to keep secret is obtained and released. In 2014 hackers calling themselves “Guardians of Peace” released e-mail from executives at the motion picture company Sony Pictures Entertainment, as well as other confidential company information. The hackers demanded that Sony Pictures not release The Interview, a comedy about a CIA plot to assassinate North Korean leader Kim Jong-Un, and threatened to attack theatres that showed the movie. After American movie theatre chains canceled screenings, Sony released the movie online and in limited theatrical release. E-mail hacking has even affected politics. In 2016, e-mail at the Democratic National Committee (DNC) was obtained by hackers believed to be in Russia. Just before the Democratic National Convention, the media organization WikiLeaks released the e-mail, which showed a marked preference of DNC officials for the presidential campaign of Hillary Clinton over that of her challenger Bernie Sanders. DNC chairperson Debbie Wasserman Schultz resigned, and some American commentators speculated that the release of the e-mail showed the preference of the Russian government for Republican nominee Donald Trump.

Sabotage

Another type of hacking involves the hijacking of a government or corporation Web site. Sometimes these crimes have been committed in protest over the incarceration of other hackers; in 1996 the Web site of the U.S. Central Intelligence Agency (CIA) was altered by Swedish hackers to gain international support for their protest of the Swedish government’s prosecution of local hackers, and in 1998 the New York Times’s Web site was hacked by supporters of the incarcerated hacker Kevin Mitnick. Still other hackers have used their skills to engage in political protests: in 1998 a group calling itself the Legion of the Underground declared “cyberwar” on China and Iraq in protest of alleged human rights abuses and a program to build weapons of mass destruction, respectively. In 2007, Estonian government Web sites, as well as those for banks and the media, were attacked. Russian hackers were suspected because Estonia was then in a dispute with Russia over the removal of a Soviet war memorial in Tallinn.

Sometimes a user’s or organization’s computer system is attacked and encrypted until a ransom is paid. The software used in such attacks has been dubbed ransomware. The ransom usually demanded is payment in a form of virtual currency, such as Bitcoin. When data are of vital importance to an organization, sometimes the ransom is paid. In 2016 several American hospitals were hit with ransomware attacks, and one hospital paid over $17,000 for its systems to be released.

Defacing Web sites is a minor matter, though, when compared with the specter of cyberterrorists using the Internet to attack the infrastructure of a nation, by rerouting airline traffic, contaminating the water supply, or disabling nuclear plant safeguards. One consequence of the September 11 attacks on New York City was the destruction of a major telephone and Internet switching centre. Lower Manhattan was effectively cut off from the rest of the world, save for radios and cellular telephones. Since that day, there has been no other attempt to destroy the infrastructure that produces what has been called that “consensual hallucination,” cyberspace. Large-scale cyberwar (or “information warfare”) has yet to take place, whether initiated by rogue states or terrorist organizations, although both writers and policy makers have imagined it in all too great detail.

In late March 2007 the Idaho National Laboratory released a video demonstrating what catastrophic damage could result from utility systems being compromised by hackers. Several utilities responded by giving the U.S. government permission to run an audit on their systems. In March 2009 the results began to leak out with a report in The Wall Street Journal. In particular, the report indicated that hackers had installed software in some computers that would have enabled them to disrupt electrical services. Homeland Security spokeswoman Amy Kudwa affirmed that no disruptions had occurred, though further audits of electric, water, sewage, and other utilities would continue.