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Cloud Computing
서울과학기술대학교
Jeilyn Molina
121336101
Cloud Computing is a general term used to describe a
new class of network based computing that takes place
over the Internet,
• basically a step on from Utility Computing
• a collection/group of integrated and networked
hardware, software and Internet infrastructure.
• Using the Internet for communication and transport
provides hardware, software and networking services
to clients
Defines cloud computing by:
• 5 essential characteristics
• 3 cloud service models
• 4 cloud deployment models
Essential characteristics
On-demand service
• Get computing capabilities as needed
automatically
Broad Network Access
• Services available over the net using
desktop, laptop, PDA, mobile phone
Essential characteristics
Resource pooling
• Provider resources pooled to server
multiple clients
Rapid Elasticity
• Ability to quickly scale in/out service
Essential characteristics
Measured service
• Control, optimize services based
on metering
Cloud service models
Software as a Service (SaaS)
• We use the provider apps
• User doesn’t manage or control the network,
servers, OS, storage or applications
Platform as a Service (PaaS)
• User deploys their apps on the cloud
• Controls their apps
• User doesn’t manage servers, IS, storage
Cloud service models
Infrastructure as a Service (IaaS)
• Consumers gets access to the infrastructure to
deploy their stuff
• Doesn’t manage or control the infrastructure
• Does manage or control the OS, storage, apps,
selected network components
Cloud Service
SalesForce CRM
Cloud deployment models
Public
• Cloud infrastructure is available to the general public,
owned by organization selling cloud services
Private
• Cloud infrastructure for single organization only, may
be managed by the organization or a 3rd party, on or
off premise
Cloud deployment models
Community
• Cloud infrastructure shared by several organizations
that have shared concerns, managed by organizations
or 3rd party
Hybrid
• 2 or more clouds bound by standard or proprietary
technology
Problems Associated with
Cloud Computing
Most security problems stem from:
• Loss of control
• Lack of trust
• Multi-tenancy
Loss of Control in the Cloud
Consumer’s loss of control
• Data, applications, resources are located with
provider
• User identity management is handled by the cloud
• User access control rules, security policies and
enforcement are managed by the cloud provider
• Consumer relies on provider to ensure
 Data security and privacy
 Resource availability
 Monitoring and repairing of services/resources
Lack of Trust in the Cloud
Defining trust and risk
• Opposite sides of the same coin
• People only trust when it pays
• Need for trust arises only in risky situations
Defunct third party management schemes
• Hard to balance trust and risk
• Is the cloud headed toward the same path?
Multi-tenancy Issues in the Cloud
Conflict between tenants’ opposing goals
• Tenants share a pool of resources and have opposing goals
How does multi-tenancy deal with conflict of interest?
• Can tenants get along together and ‘play nicely’ ?
• If they can’t, can we isolate them?
Security Issues in the Cloud
In theory, minimizing any of the issues would help:
• Loss of Control
Take back control
Data and apps may still need to be on the cloud
But can they be managed in some way by the consumer?
• Lack of trust
Increase trust (mechanisms)
Technology
Policy, regulation
Contracts
• Multi-tenancy
Private cloud
Takes away the reasons to use a cloud in the first place
VPC: its still not a separate system
Strong separation
Minimize Lack of Trust:
Policy Language
Consumers have specific security needs but don’t have a
say-so in how they are handled
• What is the provider doing for me?
• Currently consumers cannot dictate their
requirements to the provider
Standard language to convey one’s policies and expectations
• Agreed upon and upheld by both parties
• Standard language for representing Service Level
Agreement Can be used in a intra-cloud environment
to realize overarching security posture
Minimize Lack of Trust:
Policy Language
Create policy language with the following
characteristics:
• Machine-understandable
• Easy to combine/merge and compare
• Examples of policy statements are, requires isolation
between VMs, requires geographical isolation between
VMs, requires physical separation between other
communities/tenants that are in the same industry.
• Need a validation tool to check that the policy created
in the standard language correctly reflects the policy
creator’s intentions.
Minimize Lack of Trust:
Certification
Certification
• Some form of reputable, independent,
comparable assessment and description of
security features and assurance
Risk assessment
• Performed by certified third parties
• Provides consumers with additional assurance
Minimize Loss of Control
Monitoring
Utilizing different clouds
Access control management
Monitoring
Cloud consumer needs situational awareness for critical
applications
• When underlying components fail, what is the effect of the failure to the
mission logic
• What recovery measures can be taken
Requires an application-specific run-time monitoring and
management tool for the consumer
• The cloud consumer and cloud provider have different views of the
system
• Enable both the provider and tenants to monitor the components in the
cloud that are under their control
• Provide mechanisms that enable the provider to act on attacks he can
handle.
• Provide mechanisms that enable the consumer to act on attacks that he
can handle (application-level monitoring).
Utilizing different clouds
Consumer may use services from different clouds through an
intra-cloud or multi-cloud architecture
Propose a multi-cloud or intra-cloud architecture in which consumers
• Spread the risk
• Increase redundancy (per-task or per-application)
• Increase chance of mission completion for critical applications
Possible issues to consider:
• Policy incompatibility (combined, what is the overarching policy?)
• Data dependency between clouds
• Differing data semantics across clouds
• Knowing when to utilize the redundancy feature (monitoring
technology)
• Is it worth it to spread your sensitive data across multiple clouds?
 Redundancy could increase risk of exposure
Access control management
Many possible layers of access control
• E.g. access to the cloud, access to servers, access to services,
access to databases, access to Virtual Memory System, and access
to objects within a Virtual Memory
• Depending on the deployment model used, some of these will be
controlled by the provider and others by the consumer
Regardless of deployment model, provider needs to manage
the user authentication and access control procedures
• Federated Identity Management: access control management burden
still lies with the provider
• Requires user to place a large amount of trust on the provider in
terms of security, management, and maintenance of access control
policies. This can be burdensome when numerous users from
different organizations with different access control policies, are
involved
Access control management
Consumer-managed access control
• Consumer retains decision-making process to retain some control,
requiring less trust of the provider (i.e. PDP is in consumer’s domain)
• Requires the client and provider to have a pre-existing trust
relationship, as well as a pre-negotiated standard way of describing
resources, users, and access decisions between the cloud provider
and consumer. It also needs to be able to guarantee that the
provider will uphold the consumer-side’s access decisions.
• Should be at least as secure as the traditional access control model.
• Facebook and Google Apps do this to some degree, but not enough
control
• Applicability to privacy of patient health records
Access Control
Cloud Provider in Domain A
Cloud Consumer in Domain B
1. Authn request
IDP
3. Resource request (XACML Request) + SAML assertion
2. SAML Assertion
PEP
resources
.
.
.
4. Redirect to domain of resource owner
(intercepts all
resource
access requests
from all client
domains)
PDP
7. Send signed and encrypted ticket
8. Decrypt and verify signature
9. Retrieve capability from ticket
10. Grant or deny access based on capability
for cloud
resource
on Domain A
ACM
(XACML
policies)
5. Determine whether user can access
specified resource
6. Create ticket for grant/deny
Cloud Domains
Service contracts should address these 13
domains
•
•
•
•
•
•
Architectural Framework
Governance, Enterprise Risk Management
Legal, e-Discovery
Compliance & Audit
Information Lifecycle Management
Portability & Interoperability
Cloud Domains
• Security, Business Continuity, Disaster
Recovery
• Data Center Operations
• Incident Response Issues
• Application Security
• Encryption & Key Management
• Identity & Access Management
• Virtualization
Cloud Architecture
Governance
• Identify, implement process, controls to maintain
effective governance, risk management, compliance
• Provider security governance should be assessed for
sufficiency, maturity, consistency with user ITSEC
process
• Request clear docs on how facility & services are
assessed
• Require definition of what provider considers critical
services, info
• Perform full contract, terms of use due diligence to
determine roles, accountability
Legal, e-Discovery
Functional
• which functions & services in the Cloud have legal
implications for both parties
Jurisdictional
• which governments administer laws and regulations
impacting services, stakeholders, data assets
Contractual
• terms & conditions
Legal, e-Discovery
• Both parties must understand each other’s roles
Litigation hold, Discovery searches
Expert testimony
• Provider must save primary and secondary data
• Where is the data stored?
laws for cross border data flows
• Plan for unexpected contract termination and orderly
return or secure disposal of assets
• You should ensure you retain ownership of your data in
its original form
Incident Response
•
•
•
•
Cloud apps aren’t always designed with data
integrity, security in mind
Provider keep app, firewall, IDS logs?
Provider deliver snapshots of your virtual
environment?
Sensitive data must be encrypted for data breach
regulations
Encryption, Key Management
Encrypt data in transit, at rest, backup media
Secure key store
• Protect encryption keys
• Ensure encryption is based on industry/government
standards.
• Limit access to key stores
• Key backup & recoverability
ID, Access Management
Determine how provider handles:
• Provisioning
• Authentication
• Federation
• Authorization, user profile management
Virtualization
What type of virtualization is used by the
provider?
What 3rd party security technology
augments the virtual OS?
Which controls protect admin interfaces
exposed to users?
Opportunities and Challenges
The use of the cloud provides a number of
opportunities:
• It enables services to be used without any understanding of
their infrastructure.
• Cloud computing works using economies of scale:
 It potentially lowers the outlay expense for start up companies, as
they would no longer need to buy their own software or servers.
 Cost would be by on-demand pricing.
 Vendors and Service providers claim costs by establishing an ongoing revenue stream.
• Data and services are stored remotely but accessible from
“anywhere”.
Opportunities and Challenges
There has been backlash against cloud computing:
• Use of cloud computing means dependence on others and that
could possibly limit flexibility and innovation:
 The others are likely become the bigger Internet companies like Google
and IBM, who may monopolise the market.
 Some argue that this use of supercomputers is a return to the time of
mainframe computing that the PC was a reaction against.
• Security could prove to be a big issue:
 It is still unclear how safe out-sourced data is and when using these
services ownership of data is not always clear.
• There are also issues relating to policy and access:




If your data is stored abroad whose policy do you adhere to?
What happens if the remote server goes down?
How will you then access files?
There have been cases of users being locked out of accounts and
losing access to data.
Advantages of Cloud Computing
Lower computer costs:
• Do not need a high-powered and high-priced computer
to run cloud computing's web-based applications.
• Since applications run in the cloud, not on the desktop
PC, the desktop PC does not need the processing power
or hard disk space demanded by traditional desktop
software.
Advantages of Cloud Computing
Reduced software costs:
• Instead of purchasing expensive software applications
• better than paying for similar commercial software
Improved performance:
• With few large programs hogging the computer's memory,
will see better performance from your PC.
• Computers in a cloud computing system boot and run
faster because they have fewer programs and processes
loaded into memory…
Advantages of Cloud Computing
Easier group collaboration:
• Sharing documents leads directly to better collaboration.
• Many users do this as it is an important advantages of
cloud computing
Device independence.
• You are no longer tethered to a single computer or network.
• Changes to computers, applications and documents follow
you through the cloud.
• Move to a portable device, and your applications and
documents are still available.
Disadvantages of Cloud Computing
Requires a constant Internet connection:
• Cloud computing is impossible if cannot connect to the
Internet.
• Since you use the Internet to connect to both your
applications and documents, if do not have an Internet
connection you cannot access anything, even the own
documents.
Does not work well with low-speed connections:
• Similarly, a low-speed Internet connection, such as that
found with dial-up services, makes cloud computing
painful at best and often impossible.
• Web-based applications require a lot of bandwidth to
download, as do large documents.
Disadvantages of Cloud Computing
Features might be limited:
• This situation is bound to change, but today many webbased applications simply are not as full-featured as their
desktop-based applications.
For example, you can do a lot more with Microsoft PowerPoint than with
Google Presentation's web-based offering
Can be slow:
• Even with a fast connection, web-based applications can
sometimes be slower than accessing a similar software
program on the desktop PC.
• Everything about the program, from the interface to the
current document, has to be sent back and forth from the
computer to the computers in the cloud.
Disadvantages of Cloud Computing
Stored data might not be secure:
• With cloud computing, all your data is stored on the cloud.
The questions is How secure is the cloud?
• Can unauthorized users gain access to your confidential
data?
Stored data can be lost:
• Theoretically, data stored in the cloud is safe, replicated
across multiple machines.
• But on the off chance that your data goes missing, you
have no physical or local backup.
Reference
http://www.nist.gov/index.html
http://www.cloudsecurityalliance.org
http://www.revistacloudcomputing.com
http://www.ibm.com/co/services/cloud.phtml
C. Cachin, et al., "Trusting the cloud," SIGACT News, vol. 40, pp. 81-86, 2009.
R. G. Lennon, et al., "Best practices in cloud computing: designing for the cloud,"
presented at the Proceeding of the 24th ACM SIGPLAN conference companion on
Object oriented programming systems languages and applications, Orlando, Florida,
USA, 2009.
Questions??