How to Develop an Effective Security Strategy to Play in the Public Cloud
Develop an effective security strategy with the right blend of technology and processes
By: Peter Choi
Aug. 7, 2009 01:00 PM
Look all around and you can easily see that there is no shortage of press regarding the promises of cloud computing. Cloud evangelists have touted cloud computing as the next big thing, a game changer - a disruptive technology that will spark innovation and revolutionize the way businesses acquire and deliver IT services. The staggering volume of these sales pitches is to be expected, considering that cloud computing is at or near the peak of its hype cycle, but as with any new technology or model, reality will eventually set in and the public relations blitz will fade. As people continue to define cloud computing and debate its pros and cons, one thing is certain - one of the biggest obstacles to widespread cloud computing adoption will be security.
This article will deal with the security approach for the public cloud as opposed to a private, hybrid, or community cloud. The public cloud, as defined by the National Institute of Standards and Technology (NIST), is cloud infrastructure that is made available to the general public or a large industry group and is owned by an organization selling cloud services. An example of a public cloud implementation would be an application that is hosted in Amazon EC2. Anyone with a simple credit card would be able to deploy a software application in this type of environment.
Cloud Computing Styles
Benefits of the Cloud
In the cloud, enterprises can greatly reduce their capital costs and no longer have to worry about allocating time and resources to maintaining infrastructure, and patching servers and software. As a result, IT personnel can work more efficiently which in turn, can breed more innovation and help enterprises enter new markets. In the cloud, applications are accessible anywhere and at any time so employees now have more mobility. The cloud provides nearly infinite computing power and storage to enterprises and users at a mere fraction of what it would cost to actually purchase and maintain these resources. This is a huge advantage for technology startups that have limited capital. The case for moving to the cloud becomes even stronger when you consider how the troubled economy is putting pressure on businesses to cut costs.
Although surveys differ on what percentage of companies will adopt cloud computing in the next 12-24 months, enterprises are already taking cloud computing seriously. In fact, according to a recent Forrester study, one out of four large companies plans to use a cloud provider soon, or has already employed one. Furthermore, Intel predicts that by 2012, an estimated 20 to 25 percent of its server chips will be dedicated toward cloud computing data centers.
Cloud Computing in the Private and Public Sectors
Vivek Kundra, the federal CIO, is a big supporter of cloud computing. Under Kundra's leadership, the federal government has moved quickly on major cloud computing initiatives such as the General Services Administration (GSA) Storefront, an online store that will soon allow government agencies to easily procure cloud computing services. NIST has already released a working definition of cloud computing and is currently developing a Special Publication on cloud computing security.
In the defense sector, the Defense Information Systems Agency (DISA) has led the way with private cloud implementations such as Rapid Access Computing Environment (RACE) and Forge.mil. RACE gives DISA customers the ability to rent a basic computing environment. Customers purchase an environment on a monthly basis so the costs and risks of acquiring and sustaining a computing environment are significantly reduced. Forge.mil is essentially a mirror of SourceForge.net and allows developers to store and manage code for open source software projects.
Cloud Computing Security Risks
Earlier this year, a flaw in Google Docs led to the inadvertent sharing of some users' private documents with other users on the Internet without the owners' permission. There have been other highly publicized breaches and future incidents are inevitable.
Does this mean that the security risks of cloud computing outweigh its potential benefits?
Absolutely not, but customers must perform due diligence and practice due care. In addition to selecting a vendor that can comply with organizational security requirements, customers need to carefully plan and develop a defense-in-depth strategy that mitigates the security risks of cloud computing and addresses all layers of the cloud architecture.
Cloud Computing Security Approach
The design of this approach is best accomplished through the use of defense-in-depth principles, but the traditional defense-in-depth approach will have to be expanded beyond on-premise security controls to distributed and federated ones that are agile enough to be implemented in many different types of cloud architectures.
Physical and Environmental Security
Cloud providers also have the advantage of possessing many years of experience in designing and operating world class, large-scale data centers and because they have to win and maintain the confidence of their customers to maintain their business, they are highly motivated to avoid a security breach. However, none of this implies that enterprises should blindly accept any cloud provider's claims.
In addition to addressing personnel security issues, enterprises need to perform due diligence by looking for certifications and accreditations such as WebTrust/SysTrust, Statement on Accounting Standard 70 (SAS 70) and International Organization for Standardization (ISO), and verifying compliance with Sarbanes-Oxley (SOX), Federal Information Security Management Act (FISMA), Health Insurance Portability and Accountability Act (HIPAA), and the Payment Card Industry Data Security Standard (PCI DSS).
If you think that these certifications do not matter, think again. According to Verizon's "2009 Data Breach Investigations Report," 81 percent of the researched companies were not PCI compliant prior to being breached.
Customers will not have much control over the types of hypervisors their vendors will use, but it is important that they understand what security mechanisms and features are in place to secure the hypervisor layer. Proper implementation is crucial to hypervisor security as misconfiguration is one of the biggest security risks. Enterprises should understand hypervisor best practices and verify that cloud providers are incorporating them into their hypervisor solutions.
Operating System Security
Well-known hardening guides such as the DISA Security Technical Implementation Guides (STIGs) and Center for Internet Security (CIS) benchmarks can be used to effectively lock down operating system images.
By installing anti-virus software, and hardening and patching servers, the administrator protects instances against malware, keeps operating system patches current, removes all unused and unnecessary services, and ensures that only trusted parties may establish a connection to the operating system. Once an operating system image has been properly configured and hardened, the administrator can then develop a minimum security baseline and provision new, secure virtual machine images on demand. Fortunately, there are tools that can automatically assess and lock down systems.
Administrators can apply a wide range of best practices to secure web servers. A wise approach is to organize the safeguards you would like to implement and the settings that need to be configured into categories. Categories allow you to systematically walk through the hardening process using a checklist so that administrators can focus on individual categories and understand all the specific steps that are required to apply a particular countermeasure.
Most web server best practice guides incorporate the following:
Web applications are vulnerable to many different kinds of attacks (e.g., network eavesdropping, unauthorized access, and malware). To prevent eavesdropping, administrators can utilize strong authentication mechanisms (e.g., SSL with digital certificates) and secure communication channels (encrypting all traffic between the client, the application, and the database server).
Unauthorized access can be prevented by implementing firewall policies that block all traffic except authorized communication ports, disabling all unused services, limiting and periodically reviewing user membership to predefined administrative groups, restricting user access to administrative accounts created during product installation, practicing the principle of least privilege when granting permissions to new administration groups or roles, and restricting directory and file access. To mitigate the risks posed by malware, administrators should promptly apply the latest software patches, disable unused functionality, and run processes with least privileged accounts to reduce the scope of damage in the event of a compromise.
Of course, the best way to protect the application tier is to design and build secure web applications. Until recently, organizations merely talked about developing secure web applications, but the steady rise in the number and sophistication of cyber attacks over the years has forced IT professionals to move beyond mere talk. Fortunately, some real progress is being made. For example, (ISC)2 introduced a new certification last year called the Certified Secure Software Lifecycle Professional (CSSLP).
The CSSLP certification is designed to help developers understand government standards and best practices for secure software development so that security is considered and implemented throughout the entire software lifecycle. More and more security professionals are leveraging tools such as web application scanners to detect vulnerabilities and weak configuration settings. Most of the more established automated security tools offer a selection of security engines and vulnerability tests ranging from the OWASP Top 10 and ISO 27002 to HIPAA and SOX. Users can select modules or let automatic crawlers map a site's tree structure, and apply all of the selected policies' attacks from thousands of security checks.
Many of the data confidentiality obstacles can be overcome by utilizing existing technologies and solutions. While it is important to encrypt network traffic, it is just as important to encrypt data at rest. It is wise to assume that all data in the cloud can be compromised. This means that network traffic, storage, and file systems must all be encrypted. Some other best practices for database security include using roles to simplify security administration, encapsulating privileges into stored procedures, using row-level access control to enforce security policies at a row level of granularity, and building web applications so that the application users are the database users.
Virtualization brings with it a host of new threat vectors that cannot be secured with traditional security tools and methods. An owner of one VM instance may launch attacks against adjacent VMs or hackers may try to install a rogue hypervisor that can take complete control of a server. To prevent these types of attacks, enterprises need to deploy virtual firewalls and virtual IDS/IPS solutions.
These security tools are designed to protect each VM instance and can even secure live migrations of VM instances. Some VM security solutions offer protection against SQL injection attacks, cross-site scripting, and other web application vulnerabilities and can monitor unauthorized or unexpected changes to operating system files and application files.
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