4 RELATED WORK IN
SECURITY ANALYSIS OF MaaS
SYSTEMS AND APPLICATIONS
There is a vast literature in the security of Intelli-
gent Transportation Systems (ITS) and also of Inter-
net of Things (IoT) of which MaaS is an instantia-
tion of these, and are applicable to it. Callegati et.
al. (Callegati et al., 2017) mentioned ITS security
threats exploiting vulnerabilities in: (i) network se-
curity (threats such as spoofing, sniffing, Denial of
Service), (ii) data security (locality, integrity, segrega-
tion, authenticity, confidentiality, privacy, access con-
trol), (iii) authentication, identity management, sign-
on process, and authorisation, (iv) virtualisation vul-
nerability, and (v) availability. A threat is any cir-
cumstance or event with the potential to adversely
impact organisational operations and assets, individ-
uals, and/or other organisations, through an informa-
tion system via unauthorised access, destruction, dis-
closure, or modification of information, and/or de-
nial of service. Threat events are caused by threat
sources. A threat source is characterised as: (i) the
intent and method targeted at the exploitation of a vul-
nerability; or (ii) a situation and method that may ac-
cidentally exploit a vulnerability. In general, types of
threat sources include: (i) hostile cyber or physical
attacks; (ii) human errors of omission or commission;
(iii) structural failures of organisation-controlled re-
sources (e.g., hardware, software, environmental con-
trols); and (iv) natural and man-made disasters, acci-
dents, and failures beyond the control of the organi-
sation (Geer and Archer, 2012). A vulnerability is a
weakness in an information system, system security
procedures, internal controls, or implementation that
could be exploited by a threat source.
In addition to the issues mentioned in (Callegati
et al., 2017), there are other security issues pertinent
to MaaS. Data exchange and sharing are inherent in
the smooth functioning of MaaS, Viggiano et. al.
(Viggiano et al., 2020) observed that security risks
can be present if data provides special insight into in-
frastructure and the locations of the people who use
transport services which could be used in a physical
attack. They also noticed that throughout the data
management and sharing processes, there are risks
of cyber-attacks that can expose private and personal
data. Callegati et. al. (Callegati et al., 2017) ob-
served other types of security vulnerabilities pertain-
ing to MaaS operations. They observed the possibil-
ity of the presence of data leakage (which they de-
scribed as “the accidental distribution of private or
sensitive data to unauthorized entities”), the manip-
ulation of service behaviour, manipulation of service
workflows, the theft of business intelligence data, and
device misbehaviour, through actors exploiting weak-
nesses in interaction protocols of devices, applica-
tions, and services of stakeholders. Many of these
vulnerabilities and threats are exploitable by insiders,
i.e. by employees of the companies concerned. There
are other threats, such as manipulation of service be-
haviour, manipulation of service workflows, and de-
vice misbehaviour that are exploitable by outsiders,
possibly through the trust boundaries of the stake-
holders. There are various methods of MaaS security
analysis.
Traditional security analysis methods, such as
THROP (D
¨
urrwang et al., 2017), work with threat
models that are based on the fault-error-failure chain
model. While these models are valid to describe
threats to isolated components, they are insufficient
to describe system threats in complex interconnected
systems, as we have in modern MaaS systems. OC-
TAVE (Alberts et al., 1999) is a risk based strategic
assessment and planning technique for security, and
mainly used to assess an organisation’s information
security needs. OCTAVE is best suited for enterprise
information security risk assessments, which makes it
unsuitable for MaaS security which extends beyond a
single enterprise.
Therefore, in this work, we use the STRIDE
(Shostack, 2014) Threat Modelling framework to
analyse the threats that may arise in a MaaS ecosys-
tem. STRIDE takes a threat-centric approach to se-
curity analysis associating each threat with a partic-
ular asset from attackers’ perspective. An advantage
of STRIDE is that it helps change a designer’s focus
from the identification of specific attacks to focusing
on the end results of possible attacks. A second ad-
vantage is it helps to analyse the vulnerabilities that
may arise at the interface of trust boundaries of sub-
systems of an overarching system of systems, such as
a MaaS.
5 SECURITY ANALYSIS OF A
MaaS SYSTEM
The success of MaaS requires accumulation of signifi-
cant amounts of data and information, some of which
will include information about identifiable individu-
als, i.e. personal data. And, delivering a seamless
travel planning experience to users will also require
significant sharing of these data, in real-time, between
transport operators and other stakeholders. This sec-
tion describes how we have used the STRIDE Mod-
elling framework to analyse the threats and vulnera-
bilities in a MaaS system.
Provisioning Security in a Next Generation Mobility as a Service System
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