This version of the Ed-Fi ODS / API is no longer supported. See the Ed-Fi Technology Version Index for a link to the latest version.

 

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No connected technology solution is without risk. This article provides essential information for state education agencies and other platform hosts to understand where risks exist and how to mitigate risks appropriately for their organization's needs. The target audience is solution architects, developers, dev/ops personnel, and other technical professionals who deploy and host an instance of the Ed-Fi ODS / API.

Introduction

In order to support education agencies and other platform hosts in their goal of data collection and management, the Ed-Fi ODS / API technology has aligned with a set of core business processes. Some of these processes have been identified by the Alliance and the security experts with which the Alliance consults as posing a security concern. In security audit terms, the concerns discussed herein are classified as posing a moderate or lower level of risk.

The Ed-Fi Alliance takes a security-first approach to design. And, when security risks are identified, the Alliance addresses them in its technology design and code. However, in certain, select cases discussed below, the risks are a direct result of the features that support core business processes. As such, addressing the risk directly in code or architecture would in turn require fundamental business process changes by platform hosts.

As such, we present this information with two purposes:

  • To ensure platform hosts using the Ed-Fi ODS / API are aware of security concerns and to provide information on how to mitigate associated risk.
  • To invite community discussion of potential improvements to Ed-Fi technology, plus the associated systems and business processes in place at education agencies and platform hosts.

In general, the concerns of note are:

Detail about each concern follows.

District-Declared Student Enrollment

Discussion

In the as-shipped Ed-Fi ODS / API, any API client (e.g., a district student information system) with permissions to write to student enrollment records (API resource /studentSchoolAssociation) can claim enrollment of a student. Once a district client system claims this enrollment, it can read the core student record, which can include a variety of demographic and contact data.

Note that the capability to read data does not include most data linked to a student's identity, as most data is scoped to BOTH the student AND the education organization (generally the district or school). In other words, default authorization claims will not permit the reading of grade, attendance, discipline, or similar data because that data would be scoped to a different education organization.

To exploit this feature, a malicious API client would still need to gain API credentials from the state or from a district. The most likely scenarios is that a district SIS system exposes its credentials to another system.

In terms of business process, the ODS / API aligns with standard field practice. Standard practice generally allows districts to authorize client systems to declare that a given student is registered. So, this concern is not new to the community or unique to the ODS / API. The ODS / API technology has rather adapted to this existing business process. It is possible to imagine business process changes to address this weakness — such as states approving of enrollments before they occur, or of new enrollments not being allowed for previously enrolled students — but those options do not seem feasible given the limited ability of the state to validate the accuracy of district claims.

Recommendation

A recommended mitigation is to use standard IP monitoring technologies to look for connections originating from outside the state or outside of known provider (e.g., SIS vendor cloud hosting) systems.

State-Issued Sequential Student IDs

Discussion

A core principle of the Ed-Fi standards is to support the natural keys to data records, such as using state-provided student IDs to uniquely identify students, rather than requiring the use of API-assigned surrogate keys. This practice enables disparate systems to more easily coordinate, because such keys are "natural"  — that is, they already available in the ecosystem. For example, if Ed-Fi were to provide a new student ID for each student registered, that new ID would have to be propagated to all systems with which the API coordinates on a business process. If every system behaved like this, there would be massive problems mapping keys and would pose a fundamental obstacle to interoperability.

By itself, the support for natural keys is not a problem. But, security experts have noted that in many states, student IDs are assigned via sequential numbering. Because that is the case, it becomes easier for a malicious user or system to guess at new IDs. The ability to guess at identifiers for records increases risks.

Recommendation

The remediation for states or platform hosts would be to use non-sequential IDs. Such a change would require no changes to Ed-Fi technology to enhance security.

Data Sanitization

Discussion

The ODS / API is designed to protect itself from attack. Since it is primarily a recipient of data from disparate source systems, full data integrity — both in terms of business rule validation and security — is really in the hands of the upstream systems. Thus, some data strings that could be malicious in the wrong context are accepted by the ODS / API platform in the knowledge that the platform will not itself exploit them. Rather, the solution relies on a trust that both upstream and downstream systems are also employing best practices when accepting, rendering, and executing user input.

Having said that, the ODS / API is built with secure coding techniques that reject many malicious input strings and prevent their execution. But, since ODS / API instances are collection-oriented (i.e., they are filled with the reporting data that districts choose to enter, as with current education agency "spreadsheet-collection" processes) and since the number of downstream processes and technologies that data will flow into is almost never clear or fixed (it is subject to change), how to remove potentially harmful content such as cross-site scripting data is not clear.

Attempts to insert such detection into the core technology have — in the Alliance’s experience — generated large numbers of false positives that cause problems to collection efforts. These false positives can cause significant friction to business processes and the stakeholders involved, including SIS systems, district staff, and state education agency staff.

The appropriate use and implementation of data validation is a core question in the community today, and this topic will be considered in light of that discussion.

Recommendation

A best practice is for downstream systems and clients to sanitize the data before displaying or otherwise using it. Further, since those downstream applications have detailed knowledge of their environments, sanitization can be applied that considers the best possible exploit options. For example, PHP applications can sanitize for injection of PHP-based language elements, Web applications can sanitize for cross-site-scripting, and so forth.

Lockout Mechanisms

Discussion

Attackers or a malicious client application may attempt repeatedly to guess at ODS / API authentication credentials using a brute-force approach. The as-shipped Ed-Fi ODS / API does not lock out client applications after a number of failed authentication attempts. This detection is not built into the ODS / API itself for a few reasons:

  • Such detection would have to be highly configurable to be able to accommodate local business requirements, and therefore complex to implement well. 
  • Such functionality is available on the market from specialized vendors, and is often built into existing cloud-based infrastructure.

Recommendations

The Alliance recommends that API deployments configure deployment security (using firewalls or other security tools) to detect brute-force login attempts. 

This recommendation does not preclude also including security against other types of brute-force attacks such as denial-of-service attacks, brute-force SQL or SSH attacks, and similar exploits. These concerns are not discussed in detail here as this documentation is focussed on the Ed-Fi ODS / API, but the remediation for those issues are often related to the authentication lockout concern noted here.



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