SECURE VIRTUALIZATION
Benefits, Risks and Controls
Mariana Carroll
1,2
, Paula Kotzé
1,3
and Alta van der Merwe
1,2
1
Meraka Institute of the CSIR, PO Box 395, Pretoria, 0001, South Africa
2
School of Computing, University of South Africa, Pretoria, South Africa
3
Institute for ICT Advancement, Nelson Mandela Metropolitan University, Western Cape, South Africa
Keywords: Virtualization, Cloud computing, Benefits, Controls, Risks.
Abstract: Cloud computing is changing the IT delivery model to provide on-demand self-service access to a shared
pool of computing resources (physical and virtual) via broad network access to offer reduced costs,
scalability, flexibility, capacity utilization, higher efficiencies and mobility. In many instances cloud
computing builds on the capabilities of a virtualized computing infrastructure enabling multi-tenancy,
scalability and a highly abstracted cloud model. Even though cloud computing provides compelling benefits
and cost-effective options for IT hosting and expansion, security of applications and data remains a number
one business objective. It is therefore essential to ensure adequate security not only for cloud computing, but
also for the underlying technologies enabling cloud computing. Management should understand and
analyse risks in order to safeguard systems and data. The focus of this paper is on mitigation for
virtualization security risks as a fundamental step towards secure cloud computing environments.
1 INTRODUCTION
In today’s globalised, volatile and competitive
market, organizations are forced to leverage core
competencies, be agile to allow them to evolve, and
ensure that business optimization strategies are met.
Business has become increasingly reliant on IT to
support and deliver critical services and to enable
execution of strategies. The IT landscape evolved to
enable business to create a competitive advantage
through cost optimization, scalability, flexibility,
innovation and agility. Many of these benefits are
achieved through the implementation of cloud
computing and virtualization technologies.
Cloud computing provides IT resources on-
demand as a service to customers, through a
networked infrastructure, on a pay per use basis, and
often utilizes virtualization resources (Boss et al.,
2007, Cloud Security Alliance, 2009, Mell and
Grance, 2009). Cloud computing could improve the
way business and IT operate. Instead of having to
deal with the complexities and costs, applications
can now run in a shared data warehouse. Essential
cloud computing characteristics include on-demand
self-service access, broad network access, resource
pooling, rapid elasticity, measured service, multi-
tenancy and pay as you go (Centre for the Protection
of National Infrastructure (CPNI), 2010, Cloud
Security Alliance, 2009, Mell and Grance, 2009).
Cloud computing benefits include reduced costs, fast
start-up/deployments, flexibility, scalability, agility,
accessibility/mobility, increased efficiency /
productivity, resiliency and improved security
(Avanade, 2009, F5 Networks, 2009, Gadia, 2009,
Ponemon, 2010, ISACA, 2009).
Many of these cloud computing benefits, such as
reduced costs, scalability, agility, increased
efficiency and better utilization, are achieved
through virtualization (Carroll et al., 2010).
Virtualization enables multiple operating systems
and applications to run concurrently and in isolation
on a single physical host machine. It also enables
multiple virtual machines (VMs) to share the
resources of the physical host machine, ensuring
better utilization, optimization and resource
efficiency. Virtualization allows for resources to be
automatically allocated when and where needed and
for dynamic provisioning and de-provisioning (C.A.
Solutions, 2010). Through this functionality,
virtualization is seen as an enabling technology for
cloud computing (C.A. Solutions, 2010, Cloud
Security Alliance, 2009, Stratus Technologies,
15
Carroll M., Kotzé P. and van der Merwe A..
SECURE VIRTUALIZATION - Benefits, Risks and Controls.
DOI: 10.5220/0003390400150023
In Proceedings of the 1st International Conference on Cloud Computing and Services Science (CLOSER-2011), pages 15-23
ISBN: 978-989-8425-52-2
Copyright
c
 2011 SCITEPRESS (Science and Technology Publications, Lda.)

2009). Therefore, through virtualization and cloud
computing, the following can be achieved:
software-, application-, platform-, or infrastructure-
as-a-service, utility computing, server consolidation,
on-demand self-service, location independence,
multi-tenancy, scalability, reduced costs, flexibility,
better utilization, higher efficiencies and agility.
However, no technology is without risks.
Inadequate risk management could affect business
immensely, from financial losses to losing customer
goodwill and business reputation. We live in an era
of continuous change and improvement in order to
achieve and maintain a competitive advantage. This
leads to most businesses being technology pervasive,
meaning that technology represents in many
instances a valuable business asset. For
organizations to protect their business, manage IT
and comply with regulations and legislation,
management needs to identify, understand and
manage associated risks and implement appropriate
controls to safeguard IT assets and operations.
Clear guidelines indicating potential benefits and
risks are needed to assist management in assessing
the value of implementing cloud computing and
virtualization as its underlying technology against
the risks. Securing the virtualization component is
therefore an essential step for organizations to
protect their business and to manage their cloud and
IT environments effectively.
We argue that a holistic approach is required
which considers counterbalances for the risks so that
the full benefits of virtualization and cloud
technologies can be exploited. It is of no value to
have an awareness of the benefits and risks without
having a way to address the risks. The focus of this
paper is therefore to (1) provide an overview of the
benefits of virtualization, (2) highlight potential
security risks associated with virtualization, and (3)
propose a set of controls that could be considered for
the mitigation of virtualization security risks.
Section 2 provides background to the concept of
virtualization and the research process followed in
identifying the benefits, risks and mitigating
controls. An overview of the virtualization benefits
is provided in section 3 and the virtualization risks,
with specific focus on security, are described in
section 4. Security risks and considerations for
mitigation are discussed in section 5 followed by the
conclusion in section 6.
2 BACKGROUND
The IT landscape has evolved from physical, to
virtual, to the cloud through the enablement of
various technologies such as the Internet, service-
oriented architecture (SOA), virtual private networks
(VPN) and Web 2.0 (Centre for the Protection of
National Infrastructure (CPNI), 2010). Although not
required or a synonym for cloud computing,
virtualization has had a significant impact on the
computing environment through the consolidation of
computer resources for more effective and efficient
utilization.
Through virtualization technology, multiple VMs
run concurrently on a single host operating system
situated on a single physical machine. A
virtualization layer or hypervisor runs between the
physical hardware and virtual machines and is
responsible for managing and hosting the virtual
machines. Enhanced security is achieved by VMs
functioning in total isolation or silos, and no one
machine can disrupt or directly access another. IT
security policy enforcement is less complex when
applied per VM, and this also enhances
administrative control over resources (Carroll et al.,
2010).
Virtualization makes it possible for different
application versions and operating systems to run
simultaneously on a single physical machine,
resulting in increased server utilization and
optimization. This functionality, coupled with the
automated provisioning or de-provisioning and
dynamic allocation of resources, enables cloud
computing to be extremely efficient and flexible
(Boss et al., 2007).
Within the cloud environment, virtualization
allows users to access power beyond their own
physical IT environment and consequently leads to
many risks (Harauz et al., 2009). Virtualization is
therefore regarded as a core component in cloud
computing.
Security risks are addressed and controls are
proposed in this paper for mitigation of security
risks in virtual environments, which is regarded an
essential step to safeguard the cloud computing
environment.
We employed a qualitative research approach in
an extensive study of existing resources that refers to
(or sometimes only hints at) the virtualization
benefits, risks and/or consideration or mitigation of
virtualization risks. The research followed an
inductive reasoning approach, using representative
primary and secondary resources (selecting a sample
of work or texts in order to understand and
conceptualise the necessary information).
The literature review included available subject
databases, online library catalogues, published
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16

Figure 1: Virtualization benefits.
articles, relevant textbooks, industry-specific
information and trusted resources from the Internet.
The virtualization benefits and risks identified from
the extensive literature review were also tested
against primary data collected through interviews.
Interviews were conducted with 15 participants,
representing various South African organizations
and a variety of different industries. The criteria for
participation included a cloud computing and/or
virtualization interest, current or planned
implementing of cloud computing and/or
virtualization, and currently in the role of senior
management or higher. The interviews were
conducted during July 2010 and October 2010. The
construction research method was followed to
derive, analyse and present a summary of the
research findings obtained from both the literature
review and the interviews.
An overview of the resulting set of virtualization
benefits is provided in section 3, followed by the
virtualization risks, with specific focus on security,
in section 4.
3 VIRTUALIZATION BENEFITS
In the earlier part of our research, we derived a list
of virtualization benefits, which we briefly
summarize here (for a complete discussion on the
benefits the reader is referred to Carroll et al.
(2010)). The benefits are listed in Figure 1, arranged
from highest occurrence (therefore cited most in the
literature) to the lowest.
The primary benefits mentioned by most authors,
when discussing virtualization, are a reduction in
costs, server consolidation and utilization.
Major benefits include disaster recovery and
service continuity (availability), easier or quick
deployment, seamless portability and migration,
increased flexibility and service agility, reduced
downtime, easier and quicker developments and
testing, ease of management and administration,
isolation, and improved security and control.
Digital signing, duplicability, providing pre-
configured services, and segregation of production
versus development and test environments were also
cited as valuable virtualization functionalities.
Changemanagement
Reducecosts
Consolidation/Utilization
Disasterrecoveryandservicecontinuity
Reducedowntime
Makeseamless portabilitypossible
Easeofmanagement andadministration
Improvesecurityandcontrol
Isolation
Debuggingandperformance
Interoperabilitywith legacysystems
Multipleoperatingsystems
Regain/Rationalize floorspace
Scalability
Specialisationand simplicity
Supportsimulation
Robustnessandreliability
Binarycompatibility
Education
MeetSLAs
Digitalsigning
Duplicability
Providepre‐configuredservices
Segregationof
productionvs.developmentand
…
VirtualizationBenefits
Lowestoccurrence
Highestoccurrence
SECURE VIRTUALIZATION - Benefits, Risks and Controls
17

Figure 2: Virtualization risks.
4 VIRTUALIZATION RISKS
In addition to being aware of the benefits,
management should also understand and analyse the
risks posed by virtualization, and implement proper
controls to mitigate these risks.
As described in section 2, the first step in our
research was to review the published literature and
to conduct an analysis to identify virtualization risks.
This was followed by the 15 interviews to verify
and/or enhance the data obtained from the literature
review. Figure 2 presents the list of identified
virtualization risks which were summarized from the
literature review and which were confirmed by the
data collected during the interviews.
Security risks were the most common risk
experienced in virtual environments. Factors
influencing security risks include fluctuating
workloads, dynamic migration and changes,
administrator skills, knowledge and training, access
controls, hostile guests, the disappearance of
“perimeter security”, proliferation of VMs,
configuration settings, hypervisor and VM monitor
layer vulnerabilities, lack of visibility, lack of
process management, and VM server sprawl
(Barrett, 2008, Campbell and Jeronimo, 2006,
Enterprise Management Associates, 2008, Hoesing,
2006, Ormandy, 2007, VMware Inc., 2006).
Other primary risks include change management,
complexity, insufficient virtualization skills,
configuration management, under-utilization of
management and monitoring tools, single point of
failure, disaster recovery and service continuity, the
increased importance of resource functionality,
reduced access control and segregation of duties,
lack of audit capabilities and compliance, service
level management, and application and operating
system provisioning.
Difficult-to-identify use cases, incident
management, lack of time and resources, and
problem management were the risks mentioned least
frequently in the literature.
As illustrated in Table 1, information security
was rated by 91.7 percent of respondents to be the
most critical risk area for the implementation of
virtualization and cloud computing standards,
Securityadministration, management andcontrol
Changemanagement
Configurationmanagement
Virtualization complexity
Insufficientvirtualization skills
Management&monitoring tools
Singlepointoffailure
Disasterrecoveryandbusinesscontinuity…
Increasedresourcefunctionality
Lackofaudit capabilities andcompliance
Reducedaccesscontrol
Applicationprovisioning
Servicelevelmanagement
Capacitymanagement
Highcostofavailable solutions
Increasingcost ofmanagement
Operatingsystem provisioning
Segregationofduties
Difficultyinmanaging physicaland virtual
…
Internalpoliticalissues
Reducedvisibility
Applicationsareunsupported
Availabilitymanagement
Difficulttoidentifyusecases
Incidentmanagement
Lackoftime and/orpeople
Problemmanagement
VirtualizationRisks
Lowestoccurrence Highestoccurrence
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policies and controls. Disaster recovery/business
continuity planning was rated the second most
critical risk area, with a score of 66.7 percent.
Standards, policies and controls for operations
management, change management, third-
party/service level management, interface
management, and regulations and legislation were
rated as “somewhat important” for the mitigation of
risks. The findings from both the literature review
and the interviews corroborate the importance of
ensuring that the virtual environment is adequately
protected and secure. We therefore focus primarily
on security risks in the remainder of the paper.
An awareness of the risks alone would not
overcome the security issues though. What is
required is a set of controls that would allow
management to mitigate the risks appropriately. In
section 5 we will discuss the security risks in more
detail and suggest examples of controls for
mitigation of these risks in virtualized environments.
5 DISCUSSION OF SECURITY
RISKS
It was significant during the research that in a
number of instances, benefits, perceived as the main
drivers for implementing virtualization, also proved
to pose some of the most significant risks.
It is therefore imperative for management to
analyse the benefits and risks of virtualization and to
compare them in order to determine whether
implementation would be feasible, practical and
cost-effective. If the virtual solution is shown to be
feasible and the benefit outweighs the risk, it is
essential for management to implement controls,
processes and procedures to ensure that
virtualization risks are mitigated in the cloud
environment adequately and effectively.
Through the extensive literature review, the
following control objectives were identified as
important for the mitigation of virtualization security
risks in a cloud computing environment:
 Security, administration and control.
 Logical access.
 Network security.
 Physical security.
 Change control.
 Management and monitoring.
Each of these objectives is discussed in more detail
in the following sections. The discussion of each
control objective is accompanied by a table
containing a summary of the risks and
Table 1: Virtualization and cloud computing critical risk
areas.
Risk area Critical
Some-what
important
Not so
important
Information
security
91.7% 8.3% 0.0%
Operations
management
41.7% 58.3% 0.0%
Change
management
41.7% 50.0% 8.3%
Disaster
recovery/
business
continuity
planning
66.7% 33.3% 0.0%
Third-party/
service level
management
41.7% 41.7% 16.7%
Interface
management
8.3% 50.0% 41.7%
Regulations and
legislation
33.3% 41.7% 25.0%
recommendations for possible mitigation of the risk
as determined from the literature review. These
recommendations form the first steps in setting up a
complete framework for mitigating security risks
through virtualization in cloud computing settings.
5.1 Security, Administration
and Control
Virtualization improves security, administration and
control through the ability of VMs to operate in
isolation and thereby restrict security vulnerabilities
to the compromised unit only. This leads to security
policy enforcement being less complex and easily
distributed across user interfaces. Server and
hardware consolidation is further perceived to be the
most generally accepted virtualization benefit.
Consolidation leads to increased utilization and
reduced costs. Virtualization benefits such as the
ability to run different operating systems,
duplicability, seamless migration and ease of
deploying changes all contribute to the IT
department’s ability to respond promptly to
organisational needs and changing environments
(Bass, 2009, Campbell and Jeronimo, 2006,
Enterprise Management Associates, 2008, Gardner,
2009, Hoesing, 2006, Humphreys and Grieser, 2006,
Killalea, 2008, Robb, 2008, Sgallari, 2009, Sun
Microsystems Inc., 2009, VMware Inc., 2006).
In direct contrast, security administration,
management and control are also believed to
constitute the biggest virtualization risks. The
security, administration, management and control
virtualization risks and the recommendations for
mitigation of these risks are detailed in Table 2. The
risks described in Table 2 are the dynamic migration
and the seamless portability of VMs (A.1), the
SECURE VIRTUALIZATION - Benefits, Risks and Controls
19

duplicability of VMs (A.2), single target for attack
or failure (A.3), complex or inefficient provisioning
(A.4), non-compliance with licensing or service
level agreements (A.5), and audit/event logging
(A.6).
5.2 Logical Access
The logical access virtualization risks and the
recommendations for mitigation of these risks
are detailed in Table 3. Server and hardware
consolidation lead to the collapsing of domain,
Table 2: Security, administration and control risks and mitigating controls.
Ref Risk Description of mitigating control
A.1
Dynamic migration and the seamless portability of VMs between hosts
leading to inadequate change management, lack of visibility contributing
to inadequate VM tracking and an increased volume of risk exposures,
software licensing violations and misconfigurations (VMware Inc., 2006,
Ormandy, 2007, Hoesing, 2006, Enterprise Management Associates,
2008, Campbell and Jeronimo, 2006, Barrett, 2008).
Management reviews and approves the configuration and
implementation of information security tools and techniques
ensuring appropriate setup of clusters so that VMs are migrated
within secure groups and between servers with the same
infrastructure and security, and the implementation of monitoring
and management tools proving visibility to all VMs and VM
configuration (i.e. V-Tracker) (Ormandy, 2007, Gardner, 2009,
Baldwin et al., 2008).
A.2
Duplicability of VMs (creating copies of VMs by using templates or
cloning existing VMs) leading to replication of insecure security setup
based on the “templates” or cloning, increased server sprawl,
misconfigurations and inappropriate access to the cloned or newly created
VMs (VMware Inc., 2006, Ormandy, 2007, Hoesing, 2006, Enterprise
Management Associates, 2008, Campbell and Jeronimo, 2006, Barrett,
2008).
Changes to the virtual environment should be documented, tested
and approved by the appropriate level of management prior to
implementation. This includes the following change scenarios:
cloning or copying of VMs to ensure adequate and secure
configuration, controls ensuring adequate and secure setup of
VM “templates” including regular updating and patching, and
unauthorized attempts to copy or clone VMs should be detected
to ensure that sensitive information is not exposed outside secure
and authorized environments.
A.3
If the host machine is experiencing problems or if compromised, it could
have a direct impact on the virtual machine(s) being hosted. The host is
perceived as a single target for attack or failure (Hoesing, 2006,
Campbell and Jeronimo, 2006).
Security policies and minimum baseline security standards are
implemented and processes are in place to regularly review
configurations and the secure setup of the virtualization layers
(hosts) (Ormandy, 2007, Gartner Executive Programs (EXP),
2010, Baldwin et al., 2008).
A.4
Complex or inefficient provisioning due to manual procedures or lack of
adequate tools leading to errors or misconfigurations, and possible could
inhibition of the productivity of the administrators (VMware Inc., 2006,
Strom, 2008, Sgallari, 2009, Senft and Gallegos, 2009, Robb, 2008,
Newman, 2009, Killalea, 2008, Humphreys and Grieser, 2006, Hoesing,
2006, Hernandez, 2009, Gardner, 2009, Enterprise Management
Associates, 2008, Campbell and Jeronimo, 2006, Bass, 2009).
The following controls should be in place: adequate and secure
virtualization environment configuration based on approved
standards and policies, adherence to change management policies
and procedures for VMs and virtual environments, and
independent monitoring and control mechanisms to assist with
provisioning requests (Ormandy, 2007, Gardner, 2009, Baldwin
et al., 2008).
A.5
Complexities such as different virtualization vendors, multiple platforms
and lack of visibility and asset tracking could increase company risk of
non-compliance with licensing or service level agreements (Enterprise
Management Associates, 2008, Campbell and Jeronimo, 2006) as well as
more difficulties concerning security, management and control (VMware
Inc., 2006, Senft and Gallegos, 2009, Gardner, 2009, Enterprise
Management Associates, 2008, Barrett, 2008).
Management monitors and ensures that information system
service level and licensing agreements allow for all virtualization
components and requirements (Campbell and Jeronimo, 2006).
A.6
Audit/event logging was cited as a current barrier to virtualization
implementation, providing the complexities of the virtual environment.
The risk augments even further when management and monitoring tools
and controls are not adequate or efficient (VMware Inc., 2006, Enterprise
Management Associates, 2008).
Security tools are implemented to record security events (e.g.
security violation, unauthorized attempts to access VMs) for the
virtual environment. Reports are regularly reviewed and a root
cause established where applicable (Baldwin et al., 2008).
Table 3: Logical access risks and mitigating controls.
Ref Risk Description of mitigating control
B.1
A risk conveyed through server and hardware consolidation is the
collapsing of domain, security and network administrator roles. The
virtual administrator is now responsible for the entire virtual
environment, creating possible segregation of duty problems. To
further augment this risk, segregation of duty problems could also lead
to human error (as a result of not being trained properly or not
encompassing the required skill), the intentional or unintentional
disruption of critical services, and misconfiguration of VMs
(Ormandy, 2007, Hoesing, 2006, Campbell and Jeronimo, 2006).
Roles and responsibilities related to virtualization security
administration are defined and privileged access limited to
appropriate personnel based on approval from management.
Privileged access is logged and reviewed on a regular basis
(Ormandy, 2007, Hoesing, 2006, Campbell and Jeronimo, 2006,
Baldwin et al., 2008).
B.2
Server and hardware consolidation lead to the reduction of access
controls. Should an attacker gain unauthorised access to the virtual
host, access to all VMs on that host are compromised. Also, a VM
image is essentially a file containing data. The data could therefore be
copied and run in an unsecure environment circumventing security
controls and providing a means for unauthorized access to data
(Ormandy, 2007, Hoesing, 2006, Campbell and Jeronimo, 2006,
Berman, 2009).
Logical security tools and techniques are implemented to restrict
access to the virtualization layer, virtual hard disks, VM images,
data storage, VM backups, and VM management and monitoring
tools (Ormandy, 2007, Hoesing, 2006, Campbell and Jeronimo,
2006, Baldwin et al., 2008).
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security and network administrator roles (B.1) and
the reduction of access controls (B.2).
5.3 Network Security
Consolidating multiple physical servers onto a single
virtual server hosting several VMs could lead to a
number of network related risks (C.1). These
network security virtualization risks and the
recommendations for mitigation of these risks are
detailed in Table 4.
5.4 Physical Security
With the disappearance of physical data centre
perimeters, attackers could gain access to VMs from
anywhere in the network (D.1). The physical
security virtualization risk and the recommendation
for mitigation of this risk are detailed in Table 5.
5.5 Change Control
Changes are easily distributed to end-users as a
single, tested and approved virtual machine image
(Bass, 2009, Campbell and Jeronimo, 2006,
Enterprise Management Associates, 2008, Gardner,
2009, Hernandez, 2009, Hoesing, 2006, Humphreys
and Grieser, 2006, Killalea, 2008, Newman, 2009,
Robb, 2008, Senft and Gallegos, 2009, Sgallari,
2009, Strom, 2008, VMware Inc., 2006).
However, change management could become
cumbersome when the following risks, as described
in Table 6, are considered: changes to virtualization
firmware affecting all VMs on a physical host,
server sprawling, duplicability of VMs, inadequate
planning and change management procedures, and
unsupported legacy applications (E.1).
Table 4: Network security risks and mitigating controls.
Ref Risk Description of mitigating control
C.1
Consolidating multiple physical servers onto a single virtual server
hosting several VMs could lead to a number of risks. Firewalls,
intrusion detection and other protections (as known in non-virtualized
environments) are eliminated within the virtual environment, implying
the spreading of viruses and malicious software between VMs on the
same VLAN. There is also little or no visibility to detect these viruses
or malicious software. Unsecure or compromised VMs can further
serve as backdoors to the whole virtual environment (VMware Inc.,
2006, Ormandy, 2007, Hoesing, 2006, Enterprise Management
Associates, 2008, Campbell and Jeronimo, 2006, Barrett, 2008).
Network controls are in place to secure systems and prevent
unauthorised use, disclosure, damage or loss of data. Traffic between
VMs is monitored to detect any malicious software or viruses.
Table 5: Physical security risks and mitigating controls.
Ref Risk Description of mitigating control
D.1
Physical perimeters pertaining to data centers become extinct in
virtual environments. Attackers could gain access to VMs from
anywhere in the network (Ormandy, 2007, Hoesing, 2006, Campbell
and Jeronimo, 2006, Baldwin et al., 2008).
Network level security (see C.1 above). Network communication
between guest VMs should be isolated (example of a tool to use:
vShield zone from VMware).
Table 6: Change management risks and mitigating controls.
Ref Risk Description of mitigating control
E.1
Changes to virtualization firmware could affect all VMs running on a
physical host. Server sprawling could lead to reduced visibility of VMs,
therefore increasing the risk of VMs not being patched or updated
appropriately and in a timely manner to guard against exploits and
known vulnerabilities.
The easy duplication of VMs to serve as testing and development
environments could pose an easy target to obtain sensitive information
as stringent security policies are not always applied to these
environments.
The simplistic nature of applying changes in a virtual environment
could mean that proper planning does not take place and change
management procedures are not adhered to, leading to insecure setup
and misconfiguration. Inadequate patching or updating of the host
machine could affect multiple VMs residing on the host (VMware Inc.,
2006, Millard, 2008, Enterprise Management Associates, 2008,
Campbell and Jeronimo, 2006, Barrett, 2008).
Most of the time legacy applications are not supported by any
vendor, and since patches or upgrades are not produced for known
vulnerabilities it therefore also increases security-related risks
(Enterprise Management Associates, 2008).
All changes to the virtual environment (virtualization layer, host,
resources, VMs) are appropriately managed to minimize the
likelihood of disruption, unauthorized changes, or errors (i.e. buy-in
from stakeholders, compliance with policies and standards, validation
and testing of changes in separate development and testing
environments, formal approval and acceptance of changes, and
adequate security around migration to production) (Ormandy, 2007).
SECURE VIRTUALIZATION - Benefits, Risks and Controls
21

Table 7: Management and monitoring risks and mitigating controls.
Ref Risk Description of mitigating control
F.1
Risks include complexity (monitoring each layer in the virtual
configuration), single point of failure, segregation of duties,
dynamic environment leading to poor visibility, virtualization
layer abstracting rapidly and reduced supervision. An added
difficulty is also how to manage and administer both physical and
virtual environments simultaneously since virtualization creates
an extra layer inside the IT infrastructure. IP address, for instance,
is not regarded as a reliable VM identifier in a highly dynamic
environment (Humphreys and Grieser, 2006, Enterprise
Management Associates, 2008, Campbell and Jeronimo, 2006,
Barrett, 2008).
Independent management and monitoring tools are implemented
and provide for strong control and compliance reporting.
Management tools should be located in isolation, separate from
the virtual environment, to limit the risk of unauthorized access
to administration functionality (an example of such a tool is
vSphefer (VMware) which includes monitoring of the
hypervisors and VMs) (Baldwin et al., 2008).
5.6 Management and Monitoring
Management and administration of the virtual
environment is made easier through consolidation
(reducing the number of servers to maintain and
monitor), higher availability, easier and quicker
deployment, flexibility and service agility, seamless
duplication, portability and migration, effective
development and testing, and powerful debugging
and performance monitoring capabilities (Campbell
and Jeronimo, 2006, Gardner, 2009, Humphreys and
Grieser, 2006, Strom, 2008, VMware Inc., 2006).
However, risks augment if management and
monitoring tools are not used properly and regularly.
The management and monitoring virtualization risks
and the recommendations for mitigation of these
risks are detailed in Table 7. Such risks are
complexity, single point of failure, segregation of
duties, poor visibility, virtualization layer
abstracting, rapidly and reduced supervision, and
managing and administer both physical and virtual
environments (F.1).
6 CONCLUSIONS
Cloud computing and virtualization will continue to
have an important role and increasing impact on the
IT landscape. Cloud computing predictions for
growth indicate substantial developments for and
implementations of cloud computing services.
Virtualization is regarded, in many instances, as a
core component for the enablement of cloud
computing.
In this paper, we provided an overview of
virtualization benefits and security risks as a general
guideline to assist management in the
implementation of virtualization processes,
procedures and controls. The fact that virtualization
makes it possible to consolidate multiple operating
systems and applications onto a single server has
given rise to significant benefits, including hardware
and server utilization, and the reduction of hardware,
administration and management, energy efficiency,
software costs and the enablement of services
through cloud computing.
Because of the importance of virtualization in
cloud computing environments, adequate and
effective management and control around
virtualization security risks are imperative to ensure
the safeguarding of IT resources and data.
Consideration should be given to risks to ensure
completeness, integrity and availability of
applications and data.
In this paper, we suggested a number of controls
that could be considered for the mitigation of
virtualization security risks. The controls included
those related to security administration and control,
logical access, network security, physical security,
change control, and management and monitoring.
Further research focuses on the development of a
complete risk and control framework for cloud
computing and virtualization to provide management
with guidelines and control standards to deal with
cloud computing and virtualization risks coherently.
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