28 Computer Security

From wikipedia: https://en.wikipedia.org/wiki/Computer_security

Computer security, also known as cyber security or IT security, is the protection of information systems from theft or damage to the hardware, the software, and to the information on them, as well as from disruption or misdirection of the services they provide.^[1]

It includes controlling physical access to the hardware, as well as protecting against harm that may come via network access,data and code injection,^[2] and due to malpractice by operators, whether intentional, accidental, or due to them being tricked into deviating from secure procedures.^[3]

The field is of growing importance due to the increasing reliance on computer systems and the Internet in most societies,^[4]wireless networks such as Bluetooth and Wi-Fi – and the growth of “smart” devices, including smartphones, televisions and tiny devices as part of the Internet of Things.

Vulnerabilities and attacks[edit]

A vulnerability is a system susceptibility or flaw. Many vulnerabilities are documented in the Common Vulnerabilities and Exposures (CVE) database. An exploitablevulnerability is one for which at least one working attack or “exploit” exists.^[5]

To secure a computer system, it is important to understand the attacks that can be made against it, and these threats can typically be classified into one of the categories below:

Backdoors[edit]

A backdoor in a computer system, a cryptosystem or an algorithm, is any secret method of bypassing normal authentication or security controls. They may exist for a number of reasons, including by original design or from poor configuration. They may have been added by an authorized party to allow some legitimate access, or by an attacker for malicious reasons; but regardless of the motives for their existence, they create a vulnerability.

Denial-of-service attack[edit]

Denial of service attacks are designed to make a machine or network resource unavailable to its intended users.^[6] Attackers can deny service to individual victims, such as by deliberately entering a wrong password enough consecutive times to cause the victim account to be locked, or they may overload the capabilities of a machine or network and block all users at once. While a network attack from a single IP address can be blocked by adding a new firewall rule, many forms of Distributed denial of service (DDoS) attacks are possible, where the attack comes from a large number of points – and defending is much more difficult. Such attacks can originate from the zombie computers of abotnet, but a range of other techniques are possible including reflection and amplification attacks, where innocent systems are fooled into sending traffic to the victim.

Direct-access attacks[edit]

An unauthorized user gaining physical access to a computer is most likely able to directly copy data from it. They may also compromise security by making operating systemmodifications, installing software worms, keyloggers, covert listening devices or using wireless mice.^[7] Even when the system is protected by standard security measures, these may be able to be by-passed by booting another operating system or tool from a CD-ROM or other bootable media. Disk encryption and Trusted Platform Module are designed to prevent these attacks.

Eavesdropping[edit]

Eavesdropping is the act of surreptitiously listening to a private conversation, typically between hosts on a network. For instance, programs such as Carnivore andNarusInsight have been used by the FBI and NSA to eavesdrop on the systems of internet service providers. Even machines that operate as a closed system (i.e., with no contact to the outside world) can be eavesdropped upon via monitoring the faint electro-magnetic transmissions generated by the hardware; TEMPEST is a specification by the NSA referring to these attacks.

Spoofing[edit]

Spoofing, in general, is a fraudulent or malicious practice in which communication is sent from an unknown source disguised as a source known to the receiver. Spoofing is most prevalent in communication mechanisms that lack a high level of security.^[8]

Tampering[edit]

Tampering describes a malicious modification of products. So-called “Evil Maid” attacks and security services planting of surveillance capability into routers^[9] are examples.

Privilege escalation[edit]

Privilege escalation describes a situation where an attacker with some level of restricted access is able to, without authorization, elevate their privileges or access level. So for example a standard computer user may be able to fool the system into giving them access to restricted data; or even to “become root” and have full unrestricted access to a system.

Phishing[edit]

Phishing is the attempt to acquire sensitive information such as usernames, passwords, and credit card details directly from users.^[10] Phishing is typically carried out by email spoofing or instant messaging, and it often directs users to enter details at a fake website whose look and feel are almost identical to the legitimate one. Preying on a victim’s trusting, phishing can be classified as a form of social engineering.

Clickjacking[edit]

Clickjacking, also known as “UI redress attack” or “User Interface redress attack”, is a malicious technique in which an attacker tricks a user into clicking on a button or link on another webpage while the user intended to click on the top level page. This is done using multiple transparent or opaque layers. The attacker is basically “hijacking” the clicks meant for the top level page and routing them to some other irrelevant page, most likely owned by someone else. A similar technique can be used to hijack keystrokes. Carefully drafting a combination of stylesheets, iframes, buttons and text boxes, a user can be led into believing that they are typing the password or other information on some authentic webpage while it is being channeled into an invisible frame controlled by the attacker.

Social engineering[edit]

Social engineering aims to convince a user to disclose secrets such as passwords, card numbers, etc. by, for example, impersonating a bank, a contractor, or a customer.^[11]

A popular and profitable cyber scam involves fake CEO emails sent to accounting and finance departments. In early 2016, the FBI reported that the scam has cost US businesses more than $2bn in about two years.^[12]

In May 2016, the Milwaukee Bucks NBA team was the victim of this type of cyber scam with a perpetrator impersonating the team’s president Peter Feigin, resulting in the handover of all the team’s employees’ 2015 W-2 tax forms.^[13]

Systems at risk[edit]

Computer security is critical in almost any industry which uses computers. Currently, most electronic devices such as computers, laptops and cellphones come with built in firewall security software, but despite this, computers are not 100 percent accurate and dependable to protect our data (Smith, Grabosky & Urbas, 2004.) There are many different ways of hacking into computers. It can be done through a network system, clicking into unknown links, connecting to unfamiliar Wi-Fi, downloading software and files from unsafe sites, power consumption, electromagnetic radiation waves, and many more. However, computers can be protected through well built software and hardware. By having strong internal interactions of properties, software complexity can prevent software crash and security failure.^[14]

Financial systems[edit]

Web sites and apps that accept or store credit card numbers, brokerage accounts, and bank account information are prominent hacking targets, because of the potential for immediate financial gain from transferring money, making purchases, or selling the information on the black market.^[15] In-store payment systems and ATMs have also been tampered with in order to gather customer account data and PINs.

Utilities and industrial equipment[edit]

Computers control functions at many utilities, including coordination of telecommunications, the power grid, nuclear power plants, and valve opening and closing in water and gas networks. The Internet is a potential attack vector for such machines if connected, but the Stuxnet worm demonstrated that even equipment controlled by computers not connected to the Internet can be vulnerable to physical damage caused by malicious commands sent to industrial equipment (in that case uranium enrichment centrifuges) which are infected via removable media. In 2014, the Computer Emergency Readiness Team, a division of the Department of Homeland Security, investigated 79 hacking incidents at energy companies.^[16] Vulnerabilities in smart meters (many of which use local radio or cellular communications) can cause problems with billing fraud.^[17]

Aviation[edit]

The aviation industry is very reliant on a series of complex system which could be attacked.^[18] A simple power outage at one airport can cause repercussions worldwide,^[19]much of the system relies on radio transmissions which could be disrupted,^[20] and controlling aircraft over oceans is especially dangerous because radar surveillance only extends 175 to 225 miles offshore.^[21] There is also potential for attack from within an aircraft.^[22]

The consequences of a successful attack range from loss of confidentiality to loss of system integrity, which may lead to more serious concerns such as exfiltration of data, network and air traffic control outages, which in turn can lead to airport closures, loss of aircraft, loss of passenger life, damages on the ground and to transportation infrastructure. A successful attack on a military aviation system that controls munitions could have even more serious consequences.

Europe has started to move towards centralised aviation network PENS (Pan-European Network Service)^[23] which do provide a common IP-based network service across the European region covering voice and data communication and later on even more with NewPENS,^[24] similar USA has in NextGen program.^[25]

Consumer devices[edit]

Desktop computers and laptops are commonly infected with malware either to gather passwords or financial account information, or to construct a botnet to attack another target. Smart phones, tablet computers, smart watches, and other mobile devices such as Quantified Self devices like activity trackers have also become targets and many of these have sensors such as cameras, microphones, GPS receivers, compasses, and accelerometers which could be exploited, and may collect personal information, including sensitive health information. Wifi, Bluetooth, and cell phone networks on any of these devices could be used as attack vectors, and sensors might be remotely activated after a successful breach.^[26]

Home automation devices such as the Nest thermostat are also potential targets.^[26]

Large corporations[edit]

Large corporations are common targets. In many cases this is aimed at financial gain through identity theft and involves data breaches such as the loss of millions of clients’ credit card details by Home Depot,^[27] Staples,^[28] and Target Corporation.^[29] Medical records have been targeted for use in general identify theft, health insurance fraud, and impersonating patients to obtain prescription drugs for recreational purposes or resale.^[30]

Not all attacks are financially motivated however; for example security firm HBGary Federal suffered a serious series of attacks in 2011 from hacktivist group Anonymous in retaliation for the firm’s CEO claiming to have infiltrated their group, ^[31][32] and Sony Pictures was attacked in 2014 where the motive appears to have been to embarrass with data leaks, and cripple the company by wiping workstations and servers.^[33][34]

Automobiles[edit]

If access is gained to a car’s internal controller area network, it is possible to disable the brakes and turn the steering wheel.^[35] Computerized engine timing, cruise control,anti-lock brakes, seat belt tensioners, door locks, airbags and advanced driver assistance systems make these disruptions possible, and self-driving cars go even further.Connected cars may use wifi and bluetooth to communicate with onboard consumer devices, and the cell phone network to contact concierge and emergency assistance services or get navigational or entertainment information; each of these networks is a potential entry point for malware or an attacker.^[35] Researchers in 2011 were even able to use a malicious compact disc in a car’s stereo system as a successful attack vector,^[36] and cars with built-in voice recognition or remote assistance features have onboard microphones which could be used for eavesdropping.

A 2015 report by U.S. Senator Edward Markey criticized manufacturers’ security measures as inadequate, and also highlighted privacy concerns about driving, location, and diagnostic data being collected, which is vulnerable to abuse by both manufacturers and hackers.^[37]

Government[edit]

Government and military computer systems are commonly attacked by activists^{[38][39][40][41]} and foreign powers.^{[42][43][44][45]} Local and regional government infrastructure such as traffic light controls, police and intelligence agency communications, personnel records, student records,^[46] and financial systems are also potential targets as they are now all largely computerized. Passports and government ID cards that control access to facilities which use RFID can be vulnerable to cloning.

Internet of Things and physical vulnerabilities[edit]

The Internet of Things (IoT) is the network of physical objects such as devices, vehicles, and buildings that are embedded with electronics, software, sensors, and network connectivity that enables them to collect and exchange data^[47] – and concerns have been raised that this is being developed without appropriate consideration of the security challenges involved.^[48][49]

While the IoT creates opportunities for more direct integration of the physical world into computer-based systems,^[50][51] it also provides opportunities for misuse. In particular, as the Internet of Things spreads widely, cyber attacks are likely to become an increasingly physical (rather than simply virtual) threat.^[52] If a front door’s lock is connected to the Internet, and can be locked/unlocked from a phone, then a criminal could enter the home at the press of a button from a stolen or hacked phone. People could stand to lose much more than their credit card numbers in a world controlled by IoT-enabled devices. Thieves have also used electronic means to circumvent non-Internet-connected hotel door locks.^[53]

Medical devices have either been successfully attacked or had potentially deadly vulnerabilities demonstrated, including both in-hospital diagnostic equipment^[54] and implanted devices including pacemakers^[55] and insulin pumps.^[56]

Impact of security breaches[edit]

Serious financial damage has been caused by security breaches, but because there is no standard model for estimating the cost of an incident, the only data available is that which is made public by the organizations involved. “Several computer security consulting firms produce estimates of total worldwide losses attributable to virus and wormattacks and to hostile digital acts in general. The 2003 loss estimates by these firms range from $13 billion (worms and viruses only) to $226 billion (for all forms of covert attacks). The reliability of these estimates is often challenged; the underlying methodology is basically anecdotal.”^[57]

However, reasonable estimates of the financial cost of security breaches can actually help organizations make rational investment decisions. According to the classic Gordon-Loeb Model analyzing the optimal investment level in information security, one can conclude that the amount a firm spends to protect information should generally be only a small fraction of the expected loss (i.e., the expected value of the loss resulting from a cyber/information security breach).^[58]

Attacker motivation[edit]

As with physical security, the motivations for breaches of computer security vary between attackers. Some are thrill-seekers or vandals, others are activists or criminals looking for financial gain. State-sponsored attackers are now common and well resourced, but started with amateurs such as Markus Hess who hacked for the KGB, as recounted by Clifford Stoll, in The Cuckoo’s Egg.

A standard part of threat modelling for any particular system is to identify what might motivate an attack on that system, and who might be motivated to breach it. The level and detail of precautions will vary depending on the system to be secured. A home personal computer, bank, and classified military network face very different threats, even when the underlying technologies in use are similar.