Smart city solutions utilise complex, networked assemblages of digital technologies and ICT infrastructure to manage various city systems and services.  Any device that relies on software to function is vulnerable to being hacked.  If a device is networked, then the number of potential attack points multiples across the network, and the hack can be performed remotely (1). Once a single device is compromised, then the whole assemblage becomes vulnerable to cyberattacks that seek to ‘alter, disrupt, deceive, degrade or destroy computer systems and networks or the information and/or programs resident in or transiting these systems or networks’ (2).

There are three forms of cyberattack: availability attacks that seek to close a system down or deny service use; confidentiality attacks that seek to extract information and monitor activity; and integrity attacks that seek to enter a system to alter information and settings (such as changing settings so that components exceed normal performance, erasing critical software, or planting malware and viruses) (3).  The vulnerability of smart city systems is exacerbated by a number of issues including weak security and encryption; the use of insecure legacy systems and poor maintenance; large and complex attack surfaces and interdependencies; cascade effects; and human error and disgruntled (ex)employees (19).  The result is that the process of making city systems and infrastructures ‘smart’ has also made them vulnerable to a suite of cyber-threats (4,5,6).

Cyberattacks can target every type of smart city solution and particular system components. There are a number of weak points – including SCADA systems, the sensors and microcontrollers of the Internet of Things, and communication networks and telecommunication switches.

SCADA systems
Various forms of urban infrastructure, including the electricity grid, water supply, and traffic control, rely on SCADA (supervisory control and data acquisition) systems that are used to control functions and flow (4).  These systems measure how an infrastructure is performing in real-time and enable either automated or human operator interventions to change settings.  SCADA systems can be traced back to the 1920s, but were extensively rolled out in the 1980s (12).  As a consequence, many deployments are quite dated.  Many have been found to operate with their original security codes (13).  In some cases, while the infrastructure is relatively secure, the communications network is vulnerable (4).  A number of SCADA systems have been compromised, with hackers altering how the infrastructure performs, or causing a denial-of-service, or have stolen data.  Probably the most infamous SCADA hack was the 2009 Stuxnet attack on Iran’s uranium enrichment plant in which the system was infected by malware that destroyed a number of centrifuges by running them beyond their design specifications (12).  By 2010 over 90,000 Stuxnet infections were reported in 115 countries (5).

Internet of Things
The Internet of Things refers to the connecting together of machine-readable, uniquely identifiable objects across the Internet.  Some objects are passive and can simply be scanned or sensed (such as smart cards with embedded RFID chips used to access buildings and transport systems).  Others are more active and include microcontrollers and actuators.  All kinds of objects that used to be dumb, such as fridges, thermostats and lights, are now becoming networked and smart, generating information about their use and becoming controllable from a distance.  Moreover, sensors can be embedded into the urban fabric and throughout critical infrastructures to produce data concerning ‘location, proximity, velocity, temperature, flow, acceleration, sound, vision, force, load, torque, pressure, and interactions’ (13).  Sensors and microcontrollers are hackable as they often have little effective security, encryption, or privacy protocols in place.  RFID chips, for example, can be hacked, jammed and spoofed (13).

Communication networks and telecommunication switches
The Internet of Things are linked together via a number of communications technologies and protocols such as 4G LTE (Long Term Evolution), GSM (Global System for Mobile communication), CDMA (Code Division Multiple Access), WiFi, bluetooth, RFID (Radio-Frequency Identification), NFC (Near-Field Communication), ZigBee (open wireless standard), and Z-Wave (wireless communication).  Each of the modes of networking and transferring data are known to have security issues that enable data to be intercepted and provide access to devices.  Likewise, telecommunication switches that link together the local and long distance Internet infrastructure are known to have vulnerabilities including manufacturer and operator back-door security access and access codes that are infrequently updated (4).

Transport management systems and vehicles
There have been a number of cyberattacks on transport management systems in recent years, as well as proof-of-concept demonstrations of possible attacks.  For example, a cyberattack on a key toll road in Haifa, Israel, closed it for eight hours causing major traffic disruption (9).  A research team from the University of Michigan managed to hack and manipulate more than a thousand traffic lights in one city using a laptop and wireless radio (15).  Likewise, IOActive Labs have hacked traffic control sensors widely used around the world and altered traffic light sequencing and interactive speed and road signs (16).  A teenager in Lodz, Poland, managed to hack the city tram switches, causing four trams to derail and injuring a number of passengers (1, 13).  In the US, air traffic control systems have been hacked, FAA servers seized, the personal information of 58,000 workers stolen, and malicious code installed on air traffic networks (13).  Vehicles themselves are also open to being hacked given that a new car contains up to 200 sensors connected to around 40 electronic control units and can connect to wireless networks.  A recent Wired article details how two hackers were able to remotely hack a car through its Internet computer that controls entertainment and navigation systems, facilitates phone calls and can provide a wifi hotspot, using it as a route to replace firmware that enabled them to take control of the car’s internal computer network.  The hackers could then take over the driving of the car from over 10 miles away, turning the driver into a passenger (17).

Electricity grid and smart meters
The generation, transmission, and distribution of electricity are monitored and controlled using SCADA systems (12).  In addition, the electricity grid consists of a range of other networked devices.  In the case of the US energy grid over 70 percent of components are over 25 years old, including many SCADA systems (13).  Given the potential cascade effects of shutting down the electricity grid, it has been a key point of cyberattack. Electricity grid utilities in the US report being under near constant cyberattack, with one utility recording that it was the target of approximately 10,000 cyberattacks each month (all five commissioners of the Federal Energy Regulatory Commission agree that the threat of a cyber-attack on the electric grid is the top threat to electricity reliability in the United States) (8).  The Israel Electric Corp. reports that its servers register about 6,000 unique computer attacks every second, with other critical infrastructure also under continuous cyberattack (9).  As smart grids and smart meters are installed, the number of potential access points to grid networks increases enormously (12).  Smart meters themselves can be hacked with low-cost tools and readily available software to alter proof of consumption or to steal energy from other users (1, 14).

Building management systems
Building management systems are often considered an aspect of property services rather than IT services and cybersecurity is not a key issue in purchase or operation (18).  The consequence is weakly protected systems, often still configured with manufacturer codes.  Moreover manufacturers often do not have processes in place for responding to vulnerabilities or a notification process to inform customers about security threats (18).  The vulnerabilities of building management systems pose two main threats.  The first is that if they are hacked building operations could be disrupted and safety risks created.  The second is that they provide a potential route for breaking into enterprise business systems and critical company data if they share the same network.  In the case of the Target data breach in which over 100 million customer details were stolen it appears that the retailer did not properly segment its data network, with hackers gaining access through the company that maintained its heating, ventilation and air conditioning (HVAC) system (18).

Cameras
Cities are full of a plethora of CCTV cameras; some owned and controlled privately, others by public authorities and police services.  The security of these cameras is highly variable, with some lacking encryption or usernames and passwords, and others open to infection by malware and firmware modification (20).  Accessing a camera provides a means to spy on individuals, such as viewing home presence or using a bank ATM camera to monitor the digits being pressed.  Demonstrating the scale of the issue, one website provides access to the feeds of thousands of unsecured or poorly secured cameras (uses admin passwords) from 152 countries (21).  Cameras can also be turned off, with some lacking the function to be restarted remotely (19).

Many cyberattacks are relatively inconsequential, such as probes and address scans, and are unsuccessful, while a small number are much more significant and involve a security breach.  In a 2014 study of 599 utility, oil and gas, energy and manufacturing companies nearly 70 percent reported at least one security breach that led to the loss of confidential information or disruption of operations in the previous 12 months; 78 percent expected a successful attack on their ICS (industrial control systems) or SCADA systems in the next two years (10).  In 2012, 23 gas pipeline companies were hacked and source code and blueprints to facilities stolen (7).  Between 2010 and 2014, the US Department of Energy (that oversees the US power grid, nuclear arsenal, and national labs) documented 1,131 cyberattacks, of which 159 were successful (11).  In 53 cases these attacks were ‘root compromises’, meaning that the attackers gained administrative privileges to computer systems, stealing various kinds of personnel and operational information (11).

Cyberattacks can be performed by hostile nations, terrorist groups, cyber-criminals, hacker collectives, and individual hackers.  Former FBI director, Robert Mueller, details that 108 nations have cyberattack units, targeting critical infrastructure and industrial secrets (13).  The majority of attacks are presently being repulsed using cybersecurity tools, or their effects have been disruptive or damaging but not critical for the long term delivery of services (3).  Indeed, it needs to be recognised that to date, successful cyberattacks on cities are still relatively rare and when they have occurred their effects generally last no more than a few hours or involve the theft of data rather than creating life threatening situations.  That said, it is clear that there is a cybersecurity arms race underway between attackers and defenders, and that more severe disruption of critical infrastructure has been avoided through the threat of mutually assured destruction between nations (22).  This is not to suggest that smart city initiatives should be avoided, but rather that the cybersecurity challenges of creating secure smart cities should be taken seriously.  It is likely that cyberattacks will increase over time, they will become more sophisticated, and that they have the potential to cause significant disruption to city services and the wider economy and society (5).

References
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