Irs office of Safeguards Technical Assistance Memorandum Protecting Federal Tax Information (fti) In a Cloud Computing Environment




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IRS Office of Safeguards Technical Assistance Memorandum

Protecting Federal Tax Information (FTI) In a Cloud Computing Environment
September 2012 Update
Introduction

As defined by the National Institute of Standards and Technology (NIST), “Cloud computing is a model for enabling ubiquitous, convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics, three service models, and four deployment models.”


Recently the Federal Government has released the Federal Risk and Authorization Management Program (FedRAMP) to account for the unique security requirements surrounding cloud computing. FedRAMP consists of a subset of NIST 800-53 security controls targeted towards cloud provider and customer security requirements.
As agencies look to reduce costs and improve reliability of business operations, cloud computing may offer promise as an alternative to traditional data center models. By utilizing the following cloud service models, agencies may be able to reduce hardware and personnel costs by eliminating redundant operations and consolidating resources. Cloud services offered by third party providers are often tailored to provide agencies with very precise environments to meet their operating needs.
An agency’s cloud implementation is a combination of a service model and a deployment model. NIST SP 800-145 outlines the possible service models that may be employed during a cloud implementation:


  • Cloud Software as a Service (SaaS). The capability provided to the consumer is to use the provider’s applications running on a cloud infrastructure. The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.

  • Cloud Platform as a Service (PaaS). The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly application hosting environment configurations.

  • Cloud Infrastructure as a Service (IaaS). The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems; storage, deployed applications, and possibly limited control of select networking components (e.g., host firewalls).

Organizations have several choices for deploying a cloud computing model, as defined by NIST in SP 800-145:




  • Private cloud. The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.

  • Community cloud. The cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise.

  • Public cloud. The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

  • Hybrid cloud. The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds).

Based on NIST guidance, industry best practices, and the Internal Revenue Service (IRS) Publication 1075, this memo provides agencies guidance for securing FTI in a cloud environment. These preliminary requirements are subject to change, based on updated standards or guidance. Agencies and their cloud providers should also review the requirements of FedRAMP and ensure overall compliance with these guidelines.


While cloud computing offers many potential benefits, it is not without risk. The primary security concerns with cloud computing are 1) data is not stored in an agency-managed data center, 2) the agency must rely on the vendor’s security controls for protection, and 3) data from multiple customers are potentially commingled in the cloud environment.
Limiting access to authorized individuals becomes a much greater challenge with the increased availability of data in the cloud, and agencies may have greater difficulties to identify FTI when segregated or commingled in the cloud environment. Agencies that utilize a public cloud model should have increased oversight and governance over the security controls implemented by their cloud vendor. Monitoring and addressing security issues that arise with FTI in a cloud environment remain in the purview of the agency.
Mandatory Requirements for FTI in a Cloud Computing Environment (CCE)

To utilize a cloud computing model to receive, transmit, store, or process FTI, the agency must be in compliance with all Publication 1075 requirements. The following mandatory requirements are in effect for introducing FTI to a CCE:




  1. Notification Requirement. The agency must notify the IRS Office of Safeguards at least 45 days prior to transmitting FTI into a cloud environment.




  1. Data Isolation. Software, data, and services that receive, transmit, process, or store FTI must be isolated within the cloud environment so that other cloud customers sharing physical or virtual space cannot access other customer data or applications.




  1. Service Level Agreements (SLA). The agency must establish security policies and procedures based on IRS Publication 1075 for how FTI is stored, handled, and accessed inside the cloud through a legally binding contract or Service Level Agreement (SLA) with their third party cloud provider.




  1. Data Encryption in Transit. FTI must be encrypted in transit within the cloud environment. All mechanisms used to encrypt FTI must be FIPS 140-2 compliant, and operate utilizing the FIPS 140-2 compliant module. This requirement must be included in the SLA.




  1. Data Encryption at Rest. FTI must be encrypted while at rest in the cloud. All mechanisms used to encrypt FTI must be FIPS 140-2 compliant, and operate utilizing the FIPS 140-2 compliant module. This requirement must be included in the SLA.




  1. Persistence of Data in Relieved Assets. Storage devices where FTI has resided must be securely sanitized and/or destroyed using methods acceptable by National Security Agency/Central Security Service (NSA/CSS). This requirement must be included in the SLA.




  1. Risk Assessment. The agency must conduct an annual assessment of the security controls in place on all information systems used for receiving, processing, storing and transmitting FTI. For the annual assessment immediately prior to implementation of the cloud environment and each annual risk assessment (or update to an existing risk assessment) thereafter, the agency must include the cloud environment. The IRS Office of Safeguards will evaluate the risk assessment as part of the notification requirement in #1.



  2. Security Control Implementation. Customer defined security controls must be identified, documented and implemented. The customer defined security controls, as implemented, must comply with Publication 1075 requirements.

These requirements are explained in detail in the sections below.


#1 Notification

To utilize a cloud environment that receives, processes, stores or transmits FTI, the agency must meet the following mandatory notification requirements:




  • If the agency’s approved Safeguard Procedures Report (SPR) is less than six years old and reflects the agency’s current process, procedures and systems, the agency must submit the Cloud Computing Notification (see Publication 1075 Exhibit 16), which will serve as an addendum to their SPR.




  • If the agency’s SPR is more than six years old or does not reflect the agency’s current process, procedures and systems, the agency must submit a new SPR and the Cloud Computing Notification (see Publication 1075 Exhibit 16).

Before the SPR has been updated with the information from the Cloud Computing Notification Requirements, the IRS strongly recommends that a state agency planning on implementing a virtual environment contact the Office of Safeguards at SafeguardReports@irs.gov to schedule a conference call to discuss the details of the planned cloud computing implementation.


#2 Data Isolation

One of the most common compliance issues with FTI is data location. Use of an agency-owned computing center allows the agency to structure its computing environment and to know in detail where FTI is stored and what safeguards are used to protect the data. In contrast, a characteristic of many cloud computing services is that detailed information about the location of an organization’s data is unavailable or not disclosed to the service subscriber. This makes it difficult to ascertain whether sufficient safeguards are in place and whether legal and regulatory compliance requirements are being met.


IRS Publication 1075, section 5.3 recommends separating FTI from other information to the maximum extent possible. Organizing data in this manner will reduce the likelihood of unauthorized data access and disclosure. If complete separation is not possible, the agency must label FTI down to the data element level. Labeling must occur prior to introducing the data to the cloud and the data must be tracked accordingly through audit trails captured for operating systems, databases and applications that receive, store, process or transmit FTI. The agency must be able to verify with the cloud provider, at all times, where the FTI has travelled in the cloud and where it currently resides.
IRS Publication 1075, section 9.3, Audit & Accountability, states audit logs must enable tracking activities taking place on the system. IRS Publication 1075 Exhibit 9, System Audit Management Guidelines, contains requirements for creating audit-related processes at both the application and system levels. Within the application, auditing must be enabled to the extent necessary to capture access, modification, deletion and movement of FTI by each unique user. This auditing requirement also applies to data tables or databases embedded in or residing outside of the application.
#3 Service Level Agreements and Contracts

While the agency may not have direct control over FTI at all times, they ultimately maintain accountability while it is in the cloud, and the ownership rights over the data must be firmly established in the service contract to enable a basis for trust. A Service Level Agreement (SLA) is a mechanism to mitigate security risk that comes with the agency’s lack of visibility and control in a cloud environment. It is important that agencies enter into SLAs with cloud providers that clearly identify Publication 1075 security control requirements and determine who has responsibility (provider, customer) for their implementation. At a minimum, SLAs with cloud providers must include:




  • IRS Publication 1075, Exhibit 7 contract language




  • Identification of computer security requirements the cloud provider must meet. IRS Publication 1075, section 9, Computer System Security provides the security control requirements to include in agreements with third party cloud providers.




  • Identification of requirements for cloud provider personnel who have access to FTI. All cloud provider personnel with FTI access must have a justifiable need for that access and submit to a background investigation.




  • Identification of requirement that FTI may not be accessed by contractors located “offshore”, outside of the United States or its territories. Further, FTI may not be received, stored, processed or disposed via information technology systems located off-shore.




  • Identification of requirements for incident response to ensure cloud providers follow the incident notification procedures required by IRS Publication 1075. In the event of an unauthorized disclosure or data breach, the cloud provider and agency must report incident information to the appropriate Agent-in-charge, TIGTA, and the IRS Office of Safeguards within 24 hours according to Publication 1075, section 10.




  • Agreement on the scope of the security boundary for the section of the cloud where FTI is accessible and systems with FTI reside. The agency must ensure that boundary details are included in the SLA between the two parties.




  • Clearly state that agencies have the right to require changes to their section of the cloud environment, conduct inspections and Safeguard reviews, and cloud providers will comply with IT policies and procedures provided by the agency.




  • IRS Publication 1075, Exhibit 12 45-day notification requirement for notifying the IRS prior to executing any agreement to disclose FTI to a contractor the cloud vendor may utilize, or at least 45 days prior to the disclosure of FTI, to ensure appropriate contractual language is included and that contractors are held to safeguarding requirements




  • Identification of cloud provider employee awareness and training requirements for access to FTI. IRS Publication 1075, 6.2, Employee Awareness states employees must be certified to understand the agency’s security policy and procedures for safeguarding IRS information prior to being granted access to FTI, and must maintain their authorization to access FTI through annual recertification.


#4 Data Encryption in Transit

IRS Publication 1075 requires encryption of FTI in transit. The agency must ensure that encryption requirements are included in contracts with third party providers. The IRS does not advocate specific mechanisms to accomplish encryption as long as they are FIPS 140-2 compliant and configured securely. Additionally, agencies must retain control of the encryption keys used to encrypt and decrypt the FTI at all times and be able to provide information as to who has access to and knows information regarding the key passphrase.


#5 Data Encryption at Rest

In a cloud environment, protection of data and data isolation are a primary concern. Encryption of data a rest provides the agency with assurance that FTI is being properly protected in the cloud. NIST’s Draft Special Publication 800-144 recommends “Data must be secured while at rest, in transit, and in use, and access to the data must be controlled.” The IRS does not advocate specific mechanisms to accomplish encryption as long as they are FIPS 140-2 compliant and configured securely. Additionally, agencies must retain control of the encryption keys used to encrypt and decrypt the FTI at all times and be able to provide information as to who has access to and knows information regarding the key passphrase.


#6 Persistence of Data in Relieved Assets

If a storage device fails, or in situations where the data is moved within or removed from a cloud environment, actions must be taken to ensure residual FTI is no longer accessible. The destruction or sanitization methods apply to both individual devices that have failed as well as in situations where the agency removes data from the CCE or relocates FTI to another environment.


The technique for clearing, purging, and destroying media depends on the type of media being sanitized. Acceptable physical destruction methods would include disintegration, incineration, pulverizing, shredding, or melting. Repurposed media must be purged to ensure no residual FTI remains on the device. As there are varied approaches towards secure sanitization based on vendor specifications, cloud providers should consult their data storage vendor to determine the best method to sanitize the asset. If the storage device will no longer be in service, the residual data must be purged using Secure Erase or through degaussing using a NSA/CSS approved degausser. The cloud provider is required to notify the agency upon destroying or repurposing storage media. The agency must verify that FTI has been removed or destroyed and notify the IRS Office of Safeguards of the destruction of storage media in the agency’s annual Safeguard Activity Report (SAR).
#7 Risk Assessment. Agencies are required to conduct a risk assessment (or update an existing risk assessment, if one exists) when migrating FTI to a cloud environment. Subsequently, the risk assessment must be reviewed annually to account for changes to the environment. This implementation and an evaluation of the associated risks should be part of the risk assessment. The IRS Office of Safeguards will evaluate the risk assessment as part of the notification requirement in #1.
#8 Security Control Implementation. Cloud providers may designate selected controls as customer defined. For customer defined security controls, the agency must identify, document and implement the customer defined controls, in accordance with Publication 1075. Implementation of some controls may need to be done in partnership with the agency’s cloud provider, however the agency has primary responsibility for ensuring it is completed.
The agency’s capability to test the functionality and security control implementation of a subsystem within a CCE is more limited than the ability to perform testing within the agency’s own infrastructure. However, other mechanisms such as third-party assessments may be used to establish a level of trust with the cloud provider.
References:

Additional information can be obtained through the following resources:




  1. Publication 1075 Tax Information Security Guidelines for Federal, State, and Local Agencies Safeguards for Protecting Federal Tax Returns and Return Information (http://www.irs.gov/pub/irs-pdf/p1075.pdf)

  2. Federal Risk and Authorization Management Program (FedRAMP) (http://www.gsa.gov/portal/category/102371)

  3. NIST SP 800-125, Guide to Security for Full Virtualization Technologies, January 2011(http://csrc.nist.gov/publications/nistpubs/800-125/SP800-125-final.pdf)

  4. NIST SP 800-145, The NIST Definition of Cloud Computing, September 2011 (http://csrc.nist.gov/publications/nistpubs/800-145/SP800-145.pdf)

  5. NIST SP 800-144, Guidelines on Security and Privacy in Public Cloud Computing, December 2011 (http://csrc.nist.gov/publications/nistpubs/800-144/SP800-144.pdf)



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